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  • 1.
    Adli, E.
    et al.
    University of Oslo, Oslo, Norway.
    Gjersdal, H.
    University of Oslo, Oslo, Norway.
    Røhne, O.M.
    University of Oslo, Oslo, Norway.
    Dorholt, O.
    University of Oslo, Oslo, Norway.
    Bang, D.M.
    University of Oslo, Oslo, Norway.
    Thomas, D,
    ESS ERIC, Lund, Sweden.
    Shea, T.
    ESS ERIC, Lund, Sweden.
    Andersson, R.
    ESS ERIC, Lund, Sweden.
    Ibison, M.G.
    University of Liverpool and Cockcroft Institute, Daresbury, UK.
    Welsch, C.P
    University of Liverpool and Cockcroft Institute, Daresbury, UK.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    The Ess Target Proton Beam Imaging Systemas In-Kind Contribution2017Ingår i: Proceedings of IPAC2017, Copenhagen, Denmark, 2017, s. 3422-3425Konferensbidrag (Refereegranskat)
  • 2.
    Adli, Erik
    et al.
    University of Oslo, Oslo (NOR).
    Gjersdal, Håvard
    University of Oslo, Oslo (NOR).
    Sjøbæk, Kyrre N.
    University of Oslo, Oslo (NOR).
    Christoforo, Grey
    University of Oslo, Oslo (NOR).
    Fackelman, Eric D.
    University of Oslo, Oslo (NOR).
    Røhne, Ole M.
    University of Oslo, Oslo (NOR).
    Ringnes, Jonas S.
    University of Oslo, Oslo (NOR).
    Solbak, Simen R.
    University of Oslo, Oslo (NOR).
    Lithun, Maren C.
    University of Oslo, Oslo (NOR).
    Thomas, Cyrille
    ESS ERIC, Lund (SWE).
    Levinsen, Yngve
    ESS ERIC, Lund (SWE).
    Rosengren, Kaj
    ESS ERIC, Lund (SWE).
    Shea, Thomas
    ESS ERIC, Lund (SWE).
    Bell, Gerard
    STFC (GBR).
    Ibison, Mark
    University of Liverpool and Cockcroft Institute, Daresbury (GBR).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Björklund, Stefan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Progress Of The Ess Proton Beam Imaging Systems2022Ingår i: LINAC2022, ACoW Publishing , 2022, s. 395-398Konferensbidrag (Refereegranskat)
    Abstract [en]

    The ESS Target Proton Beam Imaging Systems has the objective to image the 5 MW ESS proton beam as it entersthe spallation target. The imaging systems has to operate in a harsh radiation environment, leading to a number of challenges : development of radiation hard photon sources, long and aperture-restricted optical paths and fast electronics required to provide rapid information in case of beam anomalies. This paper outlines how main challenges of the imaging systems have been addressed, and the status of deployment as ESS gets closer to beam.

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  • 3. Ajay, A.
    et al.
    Raja, V. S.
    Sivakumar, G.
    Joshi, Shrikant V.
    Hot corrosion behavior of solution precursor and atmospheric plasma sprayed thermal barrier coatings2015Ingår i: Corrosion Science, ISSN 0010-938X, E-ISSN 1879-0496, Vol. 98, s. 271-279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hot corrosion behavior of solution precursor plasma spray (SPPS) thermal barrier coating (TBC) in molten salt mixtures of 90wt.% Na<inf>2</inf>SO<inf>4</inf>+5wt.% V<inf>2</inf>O<inf>5</inf>+5wt.% NaCl and 50wt.% Na<inf>2</inf>SO<inf>4</inf>+50wt.% V<inf>2</inf>O<inf>5</inf> at 900°C is compared vis-à-vis atmospheric plasma spray (APS) coating. APS TBCs show better hot corrosion resistance than SPPS TBCs in both the salt mixtures. The vertical cracks in SPPS coatings, meant for strain tolerance and high thermal cycling life, serve as channels for transporting salts across the coating to bond coat/top coat interface and accelerate failure. © 2015 Elsevier Ltd.

  • 4.
    Algenaid, Wael
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Ganvir, Ashish
    GKN Aerospace Engine Systems, Trollhättan, Sweden.
    Calinas, Rosa Filomena
    Innovnano materials, Coimbra, Portugal.
    Varghese, Johny
    University of Hyderabad, Hyderabad, India.
    Rajulapati, Koteswararao V.
    University of Hyderabad, Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Influence of microstructure on the erosion behaviour of suspension plasma sprayed thermal barrier coatings2019Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 375, s. 86-99Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Thermal barrier coatings (TBCs) are applied on the surface of hot parts of gas turbine engines to increase the turbine efficiency by providing thermal insulation and to protect the engine parts from the harsh environment. Typical degradation of TBCs can be attributed to bond coat oxidation, thermal stress etc. In addition to this, erosion can also lead to partial or complete removal of the TBCs especially when the engine operates under erosive environment such as flying over desert area, near active volcanic or offshore ocean environment. Suspension Plasma Spraying (SPS) is a promising technique for TBC applications by virtue of its ability to produce a strain-tolerant porous-columnar microstructure that combines the benefits of both electron beam physical vapor deposited (EB-PVD) as well as atmospheric plasma sprayed (APS) coatings. This work investigates the influence of various coating microstructures produced by SPS on their erosion behavior. Six different coatings with varied microstructures produced using different suspensions with distinct characteristics were studied and their erosion resistance was compared. Results showed significant influence of SPS TBCs microstructures on the erosion resistance. Furthermore, the erosion resistance of SPS TBCs showed a close correlation between fracture toughness and the erosion rate, higher fracture toughness favours superior erosion resistance. © 2019 Elsevier B.V.

  • 5.
    Andersson, Joel
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Joshi, Shrikant V.Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).Malmsköld, LennartHögskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för produktionssystem (PS).Hanning, FabianHögskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning: Proceedings of the 11th Swedish Production Symposium (SPS2024)2024Proceedings (redaktörskap) (Refereegranskat)
    Abstract [en]

    Collaboration between those working in product development and production is essential for successful product realization. The Swedish Production Academy (SPA) was founded in 2006 with the aim of driving and developing production research and higher education in Sweden, and increasing national cooperation in research and education within the area of production.

    This book presents the proceedings of SPS2024, the 11th Swedish Production Symposium, held from 23 to 26 April 2024 in Trollhättan, Sweden. The conference provided a platform for SPA members, as well as for professionals from industry and academia interested in production research and education from around the world, to share insights and ideas. The title and overarching theme of SPS2024 was Sustainable Production through Advanced Manufacturing, Intelligent Automation and Work Integrated Learning, and the conference emphasized stakeholder value, the societal role of industry, worker wellbeing, and environmental sustainability, in alignment with the European Commission's vision for the future of manufacturing. The 59 papers included here were accepted for publication and presentation at the symposium after a thorough review process. They are divided into 6 sections reflecting the thematic areas of the conference, which were: sustainable manufacturing, smart production and automation, digitalization for efficient product realization, circular production, industrial transformation for sustainability, and the integration of education and research.

    Highlighting the latest developments and advances in automation and sustainable production, the book will be of interest to all those working in the field.

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  • 6.
    Aranke, Omkar
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Algenaid, Wael
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Awe, Samuel
    R and D Department, Automotive Components Floby AB, Floby, 52151, Sweden.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Coatings for automotive gray cast iron brake discs: A review2019Ingår i: Coatings, ISSN 2079-6412, Vol. 9, nr 9, artikel-id 552Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gray cast iron (GCI) is a popular automotive brake disc material by virtue of its high melting point as well as excellent heat storage and damping capability. GCI is also attractive because of its good castability and machinability, combined with its cost-effectiveness. Although several lightweight alloys have been explored as alternatives in an attempt to achieve weight reduction, their widespread use has been limited by low melting point and high inherent costs. Therefore, GCI is still the preferred material for brake discs due to its robust performance. However, poor corrosion resistance and excessive wear of brake disc material during service continue to be areas of concern, with the latter leading to brake emissions in the form of dust and particulate matter that have adverse effects on human health. With the exhaust emission norms becoming increasingly stringent, it is important to address the problem of brake disc wear without compromising the braking performance of the material. Surface treatment of GCI brake discs in the form of a suitable coating represents a promising solution to this problem. This paper reviews the different coating technologies and materials that have been traditionally used and examines the prospects of some emergent thermal spray technologies, along with the industrial implications of adopting them for brake disc applications. © 2019 by the authors.

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  • 7. Archana, M. S.
    et al.
    Gundakaram, R. C.
    Rao, Y. S.
    Srikanth, Vvss
    Joshi, S. V.
    Joardar, J.
    Rapid consolidation of FeAl-Fe3AlCx ultrafine composites by mechanically activated field-assisted technique2014Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 611, s. 298-305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rapid sintering of FeAl based ultrafine composites by a mechanically activated field-assisted process was evaluated. The influence of applied load and isothermal holding time on the as-sintered microstructure and mechanical properties was investigated. Hardness of the nanocomposite was determined by micro- and nano-indentation techniques, while the grain size was ascertained from electron backscatter diffraction and image analysis of scanning electron micrographs. A higher applied load as well as the isothermal holding time led to better dispersion of the in situ grown Fe3AlCx carbide particles in FeAl matrix. Significant improvement in the hardness and marginal rise in elastic constant were also observed in the fast sintered ultrafine composites when compared to previous reports. The increase in hardness was attributed to the presence of a carbide phase and fine-grained microstructure. (C) 2014 Elsevier B.V. All rights reserved.

  • 8. Archana, M. S.
    et al.
    Ramakrishna, M.
    Gundakaram, R. C.
    Srikanth, Vvss
    Joshi, S. V.
    Joardar, J.
    Nanocrystalline Phases During Mechanically Activated Processing of an Iron (Fe) Aluminum (40 at% Al) Alloy2014Ingår i: Materials and Manufacturing Processes, ISSN 1042-6914, E-ISSN 1532-2475, Vol. 29, nr 7, s. 864-869Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Influence of processing conditions on in situ generation of nanocrystalline Fe(3)AlCx and Fe-Al phases during mechanically activated annealing and sintering of Fe-40 at% Al alloy was evaluated. Fe(3)AlCx, Fe3Al and ordered FeAl phases evolved even at a low temperature of 400 degrees C. The presence of carbide phase was attributed to the free carbon originating from the organic process control agent while its formation at low temperature was correlated to fast diffusion of C in the lattice assisted by the nanocrystalline structure coupled with the presence of thermal vacancies in the Fe-40 at% Al alloy. The as-sintered composite showed improved mechanical properties.

  • 9. Archana, M. S.
    et al.
    Srikanth, Vvss
    Joshi, Shrikant. V.
    Joardar, J.
    Influence of applied pressure during field-assisted sintering of Ti(C,N)-WC-FeAl based nanocomposite2015Ingår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, nr 2, s. 1986-1993Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ti(C,N)-WC-FeAl based nanocomposites are processed by field-assisted sintering at 1500 degrees C. The phase and microstructural evolution during the process under the influence of different applied pressures of 30, 50 and 100 MPa are studied using x-ray diffraction and scanning electron microscopy. Lattice parameters of (Ti,W)(C,N) solid solution and binder phases after sintering are found to vary with applied pressure. The nanocomposite grains are observed to possess a core-rim microstructure. Microstructural variations in terms of type, size and fraction of "corerim" structure as a function of applied pressure are investigated. The hardness and indentation fracture toughness values are in the range of 17.6-18.4 GPa and 5.9-6.8 MPa root m, respectively. These values are comparable with those reported for Ti(C,N)-based composites with metal binder. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

  • 10. Aulenbach, Donald B.
    et al.
    Clesceri, Nicholas L.
    Meyer, Michael A.
    Vasundevan, Chittibabu
    Beckwith, Eileen
    Joshi, Shrikant
    Removal of heavy metals in potw using alum or sodium aluminate for phosphorus removal1984Ingår i: Proceedings of Mid-Atlantic Industrial Waste Conference, 1984, s. 318-330Konferensbidrag (Refereegranskat)
    Abstract [en]

    The addition of alum or sodium aluminate at dosages which effectively remove phosphorus is beneficial in removing copper, chromium, and lead when present in wastewaters. Chromium removal is enhanced by sodium aluminate addition, but alum does not affect chromium removal. Both types of aluminum salts appear to increase the removal of lead, but the large variance in the data does not allow this to be confirmed by the t-tests. Of the remaining metals analyzed, no difference in removal was observed with and without aluminum salt addition for cadmium or antimony, nor was there any difference in TOC removal. Mercury was effectively removed to below the detection limit by primary sedimentation, so no further removal was achieved during secondary treatment when the alum/aluminate was added. Other metals were not present in amounts above detection limits.

  • 11. Aulenbach, Donald B.
    et al.
    Meyer, Michael A.
    Beckwith, Eileen
    Joshi, Shrikant
    Vasudevan, Chittibabu
    Clesceri, Nicholas L.
    Removal of Heavy Metals in Publicly Owned Treatment Works1987Ingår i: Environmental Progress, Vol. 6, nr 2, s. 91-98Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Studies were conducted at three activated sludge treatment plants during normal operation. The heavy metals were measured in the influent to each plant, the primary sedimentation effluent where applicable, the discharge after activated sludge treatment and secondary sedimentation, and in one case after a final polishing filter. Both the soluble and the total portions were measured. Beryllium, nickel, and thallium were not found in detectable levels in any of the plant influents. Mercury was found in only trace amounts. The removals of the other metals varied considerably. No consistent conclusions can be made from the data; each metal, soluble or total fraction, and unit treatment operation must be interpreted individually. The only metal in the plant effluents consistently above the recommended limit was arsenic, and this barely above the limit, and the lead content from Fitchburg, despite 83% removal.

  • 12. Aulenbach, Donald B.
    et al.
    Meyer, Michael A.
    Vaseduvan, Chittibabu
    Beckwith, Eileen
    Greaves, Kathryn
    Joshi, Shrikant
    Cleseri, Nicholas L.
    Removal of several heavy metals in potw using aluminum salts for phosphorus removal1983Ingår i: Proceedings of the Industrial Wastes Symposia, 56th Annual WPCF Conference.; Atlanta, Ga, USA; ; Code 3809, 1983Konferensbidrag (Refereegranskat)
  • 13. Ayyangar, N. R.
    et al.
    Joshi, S. V.
    Srinivasan, K. V.
    Puranik, V. G.
    Tavale, S. S.
    Row, T. N. G.
    Polycyclic compounds. Part III1 1 For Part II, see Ref. 2.-colour and chemical constitution of 2-aryl phenalen-1-one derivatives1986Ingår i: Dyes and Pigments, Vol. 7, nr 2, s. 81-92Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The UV-visible spectra of several 3-substituted 2-aryl phenalen-1-ones and dyes such as C.I. Disperse Red 303 which incorporate the phenalen-1-one as the basic chromophore are recorded and colour-chemical constitution aspects of these compounds have been studied. The fluorescence spectral data of C.I. Disperse Red 303 revealed that the component 1 was more fluorescent than the component 2, although 2 was more bathochromic compared with 1. The difference in the fluorescence intensity has been explained on the basis of difference in polarity of the carbonyl group brought about by the positional difference of the electron donor ring sulphur atom. Confirmation of these observations was obtained by X-ray crystallographic study of component 1 of C.I. Disperse Red 303. © 1986.

  • 14. Badgujar, A. C.
    et al.
    Dhage, S. R.
    Joshi, Shrikant V.
    Process parameter impact on properties of sputtered large-area Mo bilayers for CIGS thin film solar cell applications2015Ingår i: Thin Solid Films, Vol. 589, s. 79-84Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Copper indium gallium selenide (CIGS) has emerged as a promising candidate for thin film solar cells, with efficiencies approaching those of silicon-based solar cells. To achieve optimum performance in CIGS solar cells, uniform, conductive, stress-free, well-adherent, reflective, crystalline molybdenum (Mo) thin films with preferred orientation (110) are desirable as a back contact on large area glass substrates. The present study focuses on cylindrical rotating DC magnetron sputtered bilayer Mo thin films on 300 mm × 300 mm soda lime glass (SLG) substrates. Key sputtering variables, namely power and Ar gas flow rates, were optimized to achieve best structural, electrical and optical properties. The Mo films were comprehensively characterized and found to possess high degree of thickness uniformity over large area. Best crystallinity, reflectance and sheet resistance was obtained at high sputtering powers and low argon gas flow rates, while mechanical properties like adhesion and residual stress were found to be best at low sputtering power and high argon gas flow rate, thereby indicating a need to arrive at a suitable trade-off during processing. © 2015 Elsevier B.V.

  • 15.
    Badgujar, Amol C.
    et al.
    Centre for Solar Energy Materials, ARCI, Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Dhage, Sanjay R.
    Mechanical and Aerospace Engineering Department, University of California, Los Angeles, USA .
    Process Parameter Impact on Selective Laser Ablation of Bilayer Molybdenum Thin Films for CIGS Solar Cell Applications2018Ingår i: Materials focus, ISSN 2169-429X, nr 4, s. 556-562Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cu(In,Ga)Se2 or CIGS absorber layers are a promising candidate for thin film solar cells, with efficiency exceeding 22% having already been demonstrated at the cell level and their commercialization been ramped up. Scribing by selective ablation to achieve monolithic integration is an essential step in CIGS module making to divide a large area cell into a series of inter-connected smaller cells. P1 scribing or electrical isolation of back contact is an essential part of the monolithic integration. Laser-induced scribing of Molybdenum (Mo) back contact of a CIGS solar cell is highly sensitive to process parameters like laser power, pulse duration, and pulse repetition frequency. The above parameters control the scribe width, heat affected zone and process residue directly or indirectly, thereby affecting electrical isolation and module performance. Influence of laser process parameters on scribing of a bilayer Mo thin film back contact has been investigated and is being reported. The scribes obtained employing various laser conditions were characterized for electrical isolation and analyzed by optical microscopy followed by profilometry. High-quality scribing, with a scribe width of 53 μm over a length of 300 mm, was achieved on a bilayer Mo thin film sputtered on a Soda lime glass substrate.

  • 16.
    Baiamonte, Lidia
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT). LIMS, INSTM Reference Laboratory for Engineering of Surface reatments, Department of Chemical Engineering Materials Environment, Sapienza University of Rome, Rome, ITA.
    Björklund, Stefan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Mulone, Antonio
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg.
    Klement, Uta
    Department of Industrial and Materials Science, Chalmers University of Technology, Gothenburg.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Carbide-laden coatings deposited using a hand-held high-velocity air-fuel (HVAF) spray gun2021Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 406, artikel-id 126725Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Driven by sustainability and cost considerations, there is growing interest in power generation utilizing renewable sources, especially biomass and waste. While premature degradation of power plant components due to corrosion is well-known, erosion can be a dominant damage mechanism in plants that use “pure” biomass with less corrosive elements like Cl, K, etc. Circulating fluidized bed (CFB) parts are prone to erosion-driven damage and demand periodic re-protection or replacement. In response to the above, this preliminary study evaluates a selection of complex carbide-based coatings to enhance protection against erosion to prolong service life of boiler components. Recognizing on-site coating requirements of real boiler applications, a specific focus is on evaluating performance of a hand-held high-velocity air-fuel (HVAF) spray gun and compare it with the current state-of-the-art high-velocity oxy-fuel (HVOF) deposition. Coatings developed by the above routes have been characterized with microstructural analyses, and their performance evaluated and ranked in an air-jet erosion rig at various impact angles.

  • 17. Balakrishnan, A.
    et al.
    Martin, C. L.
    Saha, B. P.
    Joshi, S.
    Modelling of compaction and green strength of aggregated ceramic powders2011Ingår i: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 94, nr 4, s. 1046-1052Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The behavior of aggregated ceramic powders is investigated using discrete element simulations. Aggregation (particles bonded by fused necks, resulting from calcination) is a common phenomenon observed during ceramic powder processing. In the present study, a small volume element of aggregated powder made of 40 spherical aggregates is modelled. Each aggregate comprises ∼500 spherical crystallites of 100 nm size. Mechanical interactions between crystallites are modelled to take into account strong bonds that form during calcination (with the possibility of breakage to model crushability), and adhesive contacts that form between submicrometer particles due to surface energy effects. The impact of having strongly bonded crystallites (high degree of calcination) or of having strongly adhesive particles (to mimic the use of a binder) is also investigated. Close die compaction and unloading from different compaction densities are carried out. It is observed that the final densification of the powder depends on the selection of process parameters like bond strength and work of adhesion between particles. This study also demonstrates a proportional relationship between the number of broken bonds in the green compacts and its strength. © 2010 The American Ceramic Society.

  • 18. Balakrishnan, A.
    et al.
    Pizette, P.
    Martin, C. L.
    Joshi, S. V.
    Saha, B. P.
    Effect of particle size in aggregated and agglomerated ceramic powders2010Ingår i: Acta Materialia, ISSN 1359-6454, E-ISSN 1873-2453, Vol. 58, nr 3, s. 802-812Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work describes the compaction of agglomerated and aggregated ceramic powders with special emphasis on the role of primary particle size. Discrete element simulations are used to model weakly bonded agglomerates as well as strongly bonded aggregates. Crushing tests are carried out to obtain the characteristic strength of single agglomerate and aggregate. Microstructure evolution and stress-strain curves indicate that aggregates undergo a brittle to plastic-like transition as particle size decreases below 50 nm. It is shown that agglomerates made of nanoparticles exhibit much greater strength than those made of micron-sized particles, with an approximately inverse linear relationship with primary particle size. Simulation of the uniaxial compaction of a representative volume element of powder demonstrates that adhesive effects are responsible for the difficulty to compact nanopowders and for the heterogeneity of microstructure prior to sintering. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  • 19. Bandyopadhyay, S.
    et al.
    Gokhale, H.
    Sundar, J. K. S.
    Sundararajan, G.
    Joshi, S. V.
    A statistical approach to determine process parameter impact in Nd: YAG laser drilling of IN718 and Ti-6Al-4V sheets2005Ingår i: Optics and lasers in engineering, ISSN 0143-8166, E-ISSN 1873-0302, Vol. 43, nr 2, s. 163-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The numerous unique advantages afforded by pulsed Nd:YAG laser systems have led to their increasing utility for producing high aspect ratio holes in a wide range of materials. Notwithstanding the growing industrial acceptance of the technique, the increasingly tighter geometrical tolerances and more stringent hole quality requirements of modern industrial components demand that "defects" such as taper, recast, spatter etc., in laser-drilled holes are minimized. Process parameters like pulse energy, pulse repetition rate, pulse duration, focal position, nozzle standoff, type of gas and gas pressure of the assist gas are known to significantly influence hole quality during laser drilling. The present study reports the use of Taguchi design of experiments technique to study the effects of the above process variables on the quality of the drilled holes and ascertain optimum processing conditions. Minimum taper in the drilled hole was considered as the desired target response. The entire study was conducted in three phases:(a) screening experiments, to identify process variables that critically influence taper in laser drilled holes, (b) Optimization experiments, to ascertain the set of parameters that would yield minimum taper and (c) validation trials, to assess the validity of the experimental procedures and results. Results indicate that laser drilling with focal position on the surface of the material being drilled and employing low level values of pulse duration and pulse energy represents the ideal conditions to achieve minimum taper in laser-drilled holes. Thorough assessment of results also reveals that the laser-drilling process, optimized considering taper in the drilled hole as the target response, leads to very significant improvements in respect of other hole quality attributes of interest such as spatter and recast as well. © 2004 Elsevier Ltd. All rights reserved.

  • 20. Bandyopadhyay, S.
    et al.
    Sarin Sundar, J. K.
    Sundararajan, G.
    Joshi, S. V.
    Geometrical features and metallurgical characteristics of Nd: YAG laser drilled holes in thick IN718 and Ti-6Al-4V sheets2002Ingår i: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 127, nr 1, s. 83-95Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Laser drilling is increasingly becoming the method of choice for precision drilling of a variety of components, particularly in the aircraft industry. Notwithstanding the current level of acceptance of laser drilling in the aerospace industry, a number of defects such as spatter, recast and taper are associated with laser drilled holes and elimination of these defects is the subject of intense research. The present paper deals with Nd:YAG laser drilling of 4 and 8mm thick sections of IN718 and Ti-6Al-4V materials. The influence of type of material and its thickness, as well as parametric impact of key process variables like pulse frequency and pulse energy, have been determined. In the course of this study, relevant geometrical features of the drilled holes, like hole diameter and taper angle, have been comprehensively investigated. In addition, all metallurgical characteristics of interest, viz extent and nature of spatter, recast and heat-affected zone, have been evaluated. Effort has also been made to obtain some insights into the evolution of a through-thickness hole during laser percussion drilling of thick sections by careful experimentation involving monitoring the progression of the drilled hole with increasing number of laser pulses. Issues pertaining to variation of taper with depth of hole, change in crater depth with progressive drilling and specific energy consumption are also discussed. © 2002 Elsevier Science B.V. All rights reserved.

  • 21. Banerjee, D.
    et al.
    Joshi, Shrikant V.
    Accuracy, Reliability and Reproducibility of Various Mechanical Test Techniques: Preface1996Ingår i: Transactions of the Indian Institute of Metals, ISSN 0019-493X, Vol. 49, nr 5, s. R1-R2Artikel i tidskrift (Övrigt vetenskapligt)
  • 22. Barick, P.
    et al.
    Prasad Saha, B.
    Mitra, R.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Effect of concentration and molecular weight of polyethylenimine on zeta potential, isoelectric point of nanocrystalline silicon carbide in aqueous and ethanol medium2015Ingår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 41, nr 3, s. 4289-4293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of dispersant concentration and its molecular weight on zeta potential of nanocrystalline silicon carbide in an aqueous medium was investigated. An increase in the concentration of the dispersant, such as polyethylenimine (PEI), in slurry prepared from nanosized silicon carbide, was found to augment the iso-electric point and zeta potential. However, the zeta potential was observed to decline as the pH of the slurry shifts towards the basic region. This aforementioned behavior is attributed to the enhanced mutual repulsion between the polymer chains of the dispersant adsorbed on the surfaces of SiC particles and those approaching the surfaces. The higher ionization potential of polymers in the acidic region compared to the basic region increases the adsorption. The relationship between zeta potential and pH is however, noted to remain virtually unchanged with molecular weight of PEI. Further, it is observed that zeta potential of SiC decreases with the increase in solid content of the slurry. Rheology study reveals that the ethanol based slurry has a lower viscosity than the water based slurry, making ethanol the preferred dispersing medium for colloidal processing of nanometric SiC powder. © 2014 Elsevier Ltd and Techna Group S.r.l.

  • 23.
    Barick, Prasenjit
    et al.
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad, 500005 Telangana, India.
    Chakravarty, Dibyendu
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad, 500005 Telangana, India.
    Saha, Bhaskar Prasad
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad, 500005 Telangana, India.
    Nitra, Rahul
    Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur, 721302 West Bengal, India.
    Joshi, Shrikant
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad, 500005 Telangana, India.
    Effect of pressure and temperature on densification, microstructure and mechanical properties of spark plasma sintered silicon carbide processed with β-silicon carbide nanopowder and sintering additives2016Ingår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 42, nr 3, s. 3836-3848Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of applied pressure and temperature during spark plasma sintering (SPS) of additive-containing nanocrystalline silicon carbide on its densification, microstructure, and mechanical properties have been investigated. Both relative density and grain size are found to increase with temperature. Furthermore, with increase in pressure at constant temperature, the relative density improves significantly, whereas the grain size decreases. Reasonably high relative density (~96%) is achieved on carrying out SPS at 1300 °C under applied pressure of 75 MPa for 5 min, with a maximum of ~97.7% at 1500 °C under 50 MPa for 5 min. TEM studies have shown the presence of an amorphous phase at grain boundaries and triple points, which confirms the formation of liquid phase during sintering and its significant contribution to densification of SiC at relatively lower temperatures (≤1400 °C). The relative density decreases on raising the SPS temperature beyond 1500 °C, probably due to pores caused by vaporization of the liquid phase. Whereas β-SiC is observed in the microstructures for SPS carried out at temperatures ≤1500 °C, α-SiC evolves and its volume fraction increases with further increase in SPS temperatures. Both hardness and Young׳s modulus increase with increase in relative density, whereas indentation fracture toughness appears to be higher in case of two-phase microstructure containing α and β-SiC.

  • 24.
    Barick, Prasenjit
    et al.
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad-500005, Telangana, India.
    Saha, Bhaskar Prasad
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad-500005, Telangana, India.
    Joshi, Shrikant
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW). International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur Post, Hyderabad-500005, Telangana, India.
    Mitra, Rahul
    Department of Metallurgical and Materials Engineering, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal, 721302, India.
    Spray-freeze-dried nanosized silicon carbide containing granules: Properties, compaction behaviour and sintering2016Ingår i: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 36, nr 16, s. 3863-3877Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spherical granules comprising silicon carbide nanoparticles have been produced with the help of sprayfreeze-drying (SFD) technique. The effect of solid loading of slurries on rheological properties, flowability and morphology of the resulting SFD granules has been studied. Further, a systematic study has been performed to investigate the effect of applied pressures and granule density on the relative densities and microstructures of the green compacts. A marginal increase in viscosity is noted as the solid content of slurries increases from 5 to 15 vol% with significant increase in viscosity being observed in case of 18 vol% slurry. The granules prepared from SiC slurries are spherical in shape with their mean size, density, gravimetric flow rate, and yield strength increasing with the increase in solid content. The mechanical properties of sintered SiC produced from SFD granules are found relatively superior to that made from commercially available spray-dried (SD) granules.

  • 25. Basu, A.
    et al.
    Chakraborty, J.
    Shariff, S. M.
    Padmanabham, G.
    Joshi, S. V.
    Sundararajan, G.
    Dutta Majumdar, J.
    Manna, I.
    Laser surface hardening of austempered (bainitic) ball bearing steel2007Ingår i: Scripta Materialia, ISSN 1359-6462, E-ISSN 1872-8456, Vol. 56, nr 10, s. 887-890Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study concerns laser surface hardening (LSH) of austempered SAE 52100 steel to enhance hardness and wear resistance. Following LSH with selected laser parameters, surface microstructure and mechanical properties were evaluated by optical/scanning electron microscopy, X-ray diffraction, hardness measurement and wear studies, and thermal profile modeling. The results suggest that LSH could develop residual compressive stress and high hardness and wear resistance in this steel without affecting the bainitic core. © 2007 Acta Materialia Inc.

  • 26.
    Bellippady, Madhura
    et al.
    Högskolan Väst.
    Florent, Manon
    Högskolan Väst.
    Björklund, Stefan
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Li, Xin Hai
    mens Energy AB, Finspang (SWE).
    Robert, Frykholm
    Hoganas AB, Hoganas (SWE).
    Kjellman, Björn
    GKN Aerospace AB, Trollhattan (SWE).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Markocsan, Nicolaie
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Characteristics and performance of suspension plasma sprayed thermal barrier coatings on additively manufactured superalloy substrates2023Ingår i: Surface and Coatings Technology, ISSN 0257-8972, Vol. 472, artikel-id 129926Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex-shaped hot-section parts of new-generation turbine engines demand unique design solutions. Additive Manufacturing (AM) is an emergent production method that can produce metallic parts with complex geometries and minimal material wastage. In this work, the characteristics and performance behavior of Thermal Barrier Coatings (TBCs) deposited on forged and AM-built HAYNES®282® superalloy substrates were studied and compared. The bond coats were produced by High-Velocity Air-Fuel (HVAF) spraying using NiCoCrAlY powder feedstock and TBC top-coats by Suspension Plasma Spraying (SPS) using water- and ethanol-based suspensions of Yttria-Stabilized Zirconia (YSZ). The microstructural features, adhesion, Thermal Cycling Fatigue (TCF) lifetime, and thermal shock lifetimes of the TBCs were comprehensively investigated. The results showed that the deposition of bond coats reduced the roughness and asperities of the AM-built substrates. Depending on the type of suspension used and the spray parameters employed, the TBCs exhibited vertically cracked and columnar microstructures. However, no significant differences in TCF and thermal shock lifetimes of TBCs on AM and forged substrates were observed. It is demonstrated that TBC systems can be produced on AM-built metallic substrates, and the resulting TBCs can have similar microstructures and properties as TBCs deposited on conventional substrates.

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  • 27. Bharadwaj, Sanjay
    et al.
    Jain, Karuna
    Joshi, Shrikant V.
    A Review of Technology Commercialization Models: Suitability for Indian Research and Technology Organizations (RTOs) in Advanced Materials Sector2012Ingår i: International Journal of Business Administration & Management, Vol. 2, nr 1, s. 53-60Artikel i tidskrift (Refereegranskat)
  • 28. Bharadwaj, Sanjay
    et al.
    Padmanabham, G.
    Jain, Karuna
    Momaya, K.
    Joshi, Shrikant V.
    Strategic Alliances for Advanced Materials Technologies' Value Chain: Research and Technology Organisation (RTO)’s Perspective2014Ingår i: Proceedings of 2nd International Conference on Management of Intellectual Property Rights and Strategy / [ed] Shishir K Jha & Gouri Gargate (eds.), 2014Konferensbidrag (Refereegranskat)
  • 29. Bhardwaj, Sanjay
    et al.
    Jain, Karuna
    Joshi, Shrikant V.
    Technology Commercialization by Micro, Small and Medium Enterprises (MSMEs) in Indian Context: Challenges and Governmental Support Systems2013Ingår i: Indian Journal of Economics and Business, ISSN 0972-5784, Vol. 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Post-liberalization, level of protection imparted by Indian government to Micro, Small and Medium Enterprises (MSMEs) is gradually reducing. In the changed scenario, MSMEs need to complete with large companies, both Indian and foreign, with cost-competitive and good quality products. Due to limited resources available with MSMEs, they find it difficult to develop internal technologies and hence need to access technologies developed elsewhere. Technologies developed by public funded Research and Technology Organizations (RTOs) can support MSMEs. However, MSMEs should develop competence to commercialize technologies procured from public-funded RTOs, and also utilize available governmental support to meet the emerging challenges. This paper discusses the challenges and governmental support systems for technology commercialization, with relevant examples, from Indian MSMEs’ perspective.

  • 30.
    Bhardwaj, Sanjay
    et al.
    International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.
    Padmanabham, G.
    International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.
    Jain, Karuna
    National Institute of Industrial Engineering (NITIE), Mumbai, India.
    Srinivasa Rao, D.
    International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad, India.
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Technology commercialization in advanced materials sector: Indian context2017Ingår i: Journal of Intellectual Property Rights, ISSN 0971-7544, E-ISSN 0975-1076, Vol. 22, nr 3, s. 154-167Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study is aimed at developing insights into the Technology Value Chain (TVC) of advanced materials-based technologies using a scenario in which technology has been transferred by a Research and Technology Organization (RTO) to a Small and Medium Enterprise (SME) in the Indian context. A Conceptual Theoretical Model (CTM) using constructs from existing TVC models is used as a basis for the case study described in this paper. This model is refined using actual evidence from an Indian RTO - the International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Hyderabad. The TVC of ARCI’s proprietary Detonation Spray Coating (DSC) technology is used to expand upon the CTM as well as to provide new insights wherever possible. The TVC adopted for DSC includes technology incubation and proof of concept in advance of transferring the technology. These strategies, aided by government funding of the technology recipient companies, were observed to play an important role in successful commercialization. © 2017, National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved.

  • 31.
    Björklund, Stefan
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Goel, Sneha
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Function-dependent coating architectures by hybrid powder-suspension plasma spraying: Injector design, processing and concept validation2018Ingår i: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 142, s. 56-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The attractive properties achieved by Suspension Plasma Spraying (SPS), combined with the availability of high throughput capable plasma spray systems that permit axial feeding, provide encouragement to explore use of suspensions for next generation functional applications. This paper deals with realization of coatings with various pre-determined function-dependent architectures by employing a hybrid powder-suspension feedstock. Some illustrative application-relevant coating architecture designs are discussed, along with the specific benefits that can accrue by deploying a multi-scale powder-suspension feedstock combination. An elegant feedstock delivery arrangement to enable either simultaneous or sequential feeding of powders and suspensions to enable convenient processing of coatings with desired architectures is presented. As proof-of-concept, deposition of layered, composite and functionally graded coatings using the above system is also demonstrated using appropriate case studies

  • 32. Chakravarty, D.
    et al.
    Tiwary, C. S.
    Machado, L. D.
    Brunetto, G.
    Vinod, S.
    Yadav, R. M.
    Galvao, D. S.
    Joshi, Shrikant V.
    Sundararajan, G.
    Ajayan, P. M.
    Zirconia-Nanoparticle-Reinforced Morphology-Engineered Graphene-Based Foams2015Ingår i: Advanced Materials, Vol. 27, nr 31, s. 4534-4543Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The morphology of graphene-based foams can be engineered by reinforcing them with nanocrystalline zirconia, thus improving their oil-adsorption capacity; This can be observed experimentally and explained theoretically. Low zirconia fractions yield flaky microstructures where zirconia nanoparticles arrest propagating cracks. Higher zirconia concentrations possess a mesh-like interconnected structure where the degree of coiling is dependant on the local zirconia content. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 33. Chatterjee, M.
    et al.
    Ray, J.
    Chatterjee, A.
    Ganguli, D.
    Joshi, S. V.
    Srivastava, M. P.
    Thermal barrier coatings from sol-gel-derived spray-grade Y2O3-ZrO2 microspheres1993Ingår i: Journal of Materials Science, Vol. 28, nr 10, s. 2803-2807Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the development of ceramic thermal barrier coatings, spray-grade yttria-stabilized zirconia microspheres were prepared by the sol-gel technique. Oxide microspheres were obtained by calcination of the corresponding gel spheres at 1000 °C. Scanning electron microscopic and optical microscopic observations revealed the material thus obtained to have a predominantly spherical morphology and the requisite size distribution (5-50 μm). The dense, calcined microspheres showed good flowability. X-ray diffraction studies indicated the presence of the tetragonal polymorph of ZrO2 as the major phase, in addition to about 14% monoclinic ZrO2. The plasma-sprayed YSZ coatings made from the sol-gel-derived microspheres showed a further decrease in the monoclinic ZrO2 content (6%). The coatings survived 40-50 thermal cycles (30 min at 1200 °C followed by a water quench), indicating good thermal shock resistance. © 1993 Chapman &amp; Hall.

  • 34.
    Chauhan, Hetal R.
    et al.
    Sardar Vallabhbhai Patel Institute of Technology (SVIT), Vasad, Gujarat (IND).
    Saladi, Sekar
    Sardar Vallabhbhai Patel Institute of Technology (SVIT), Vasad, Gujarat (IND).
    Variya, Sahil
    Sardar Vallabhbhai Patel Institute of Technology (SVIT), Vasad, Gujarat (IND).
    Solanki, Ajaykumar
    ardar Vallabhbhai Patel Institute of Technology (SVIT), Vasad, Gujarat (IND).
    Tailor, Satish
    Metallizing Equipment Co. Pvt. Ltd. (MECPL), Jodhpur, Rajasthan,(IND).
    Sooraj, K. P.
    Institute for Plasma Research (IPR), Gandhinagar, Gujarat (IND).
    Ranjan, Mukesh
    Institute for Plasma Research (IPR), Gandhinagar, Gujarat (IND).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Role of micro- and nano-CeO2 reinforcements on characteristics and tribological performance of HVOF sprayed Cr3C2-NiCr coatings2023Ingår i: Surface and Coatings Technology, ISSN 0257-8972, Vol. 467, artikel-id 129684Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present study investigates the role of micro- and nano-CeO2 reinforcements on microstructural, mechanical and tribological properties of Cr3C2-NiCr coatings deposited using high-velocity-oxy-fuel (HVOF) spray process. A novel blending method involving ultrasonication, magnetic stirring and 3D-tumbler mixing was used to prepare the micro- and nano-CeO2 reinforced Cr3C2-NiCr feedstock powders. Unreinforced Cr3C2-NiCr coatings were also prepared for comparison purposes. X-ray diffraction, FE-SEM, EDS mapping, optical microscopy and optical profilometry were used to characterize the coatings. Tribological studies were performed on the coatings using modular ball-on-disc tribometer. The results showed that nano-CeO2 reinforced coatings yielded considerable reduction in porosity, surface roughness and CoF values while significantly enhancing the hardness and fracture toughness in comparison to the micro-CeO2 reinforced and unreinforced Cr3C2-NiCr coatings. The addition of nanoCeO2 to the coatings contributed to the microstructure refinement and to the formation of stable tribo-oxide layer, resulting in a lower specific wear rate under identical test conditions. Performance of micro-CeO2 reinforced coatings was intermediate to that of nano-CeO2 reinforced and unreinforced Cr3C2-NiCr coatings.

  • 35.
    Choudary Ratnala, Dilipkumar
    et al.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Andersson, Joel
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för svetsteknologi (SV).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Development of Functionally Graded Metal–Ceramic Systems by Directed Energy Deposition: A Review2023Ingår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 1107, s. 105-110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Ceramics and metals are the two vastly explored classes of materials whose individual characteristics and targeted applications differ significantly. Continuous thrust for space exploration and energy generation demands materials with a wide range of properties. To tackle this demand, ceramic-metal combined structures that club heat, wear, and corrosion resistance of ceramics to the high toughness, good strength, and better machinability of metals are desirable. While various processing routes to combine ceramics and metals have been developed through the years, solutions to address problems associated with the interface, thermal property mismatch, and poor adhesion need to be explored. In this context, Functional Graded Materials (FGMs) have attracted particular attention by virtue of their ability to avoid sharp interfaces and local stress concentrations. Out of all, Additive Manufacturing (AM) routes, particularly the Directed Energy Deposition (DED) technique, is emerging as a productive technique capable of fabricating a wide range of metal-ceramic graded structures. This paper specifically discusses metal-ceramic FGMs ́ capability as a potential high-temperature material with customized multifunctional material properties. It further outlines the primary concerns with the realization of metal-ceramic graded structures and major techniques developed to mitigate problems encountered in processing them. Specific emphasis is laid on the powder-based Laser DED (L-DED) technique of FGM fabrication owing to its control over complex geometries and microstructural engineering.

  • 36.
    Curry, Nicholas
    et al.
    Thermal Spray Innovations, Salzburg, (AUT).
    Mahade, Satyapal
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Venkat, Abhilash
    Department of Mechanical Engineering, SASTRA University, (IND).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Erosion performance of suspension plasma spray thermal barrier coatings: A comparison with state of art coatings2022Ingår i: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 437, artikel-id 128311Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Suspension plasma spray (SPS) thermal barrier coatings are currently at an early stage of industrial adoption. There remain questions about the performance of SPS columnar coatings under different engine environmental conditions as it may influence which established engine coatings can be replaced by SPS coatings. One particular area of concern has been the erosion resistance of SPS coatings.In this study a columnar SPS coating has been evaluated against three types of state of art air plasma spray coatings: conventional porous coating, high porosity coating and dense vertically cracked coating. Air-jet erosion testing was performed on coatings at a glancing angle of 30 degrees and with direct impact at 90 degrees. Coatings have been ranked according to their mass loss per unit erodent mass. Coatings were also evaluated for their microstructure, porosity content, hardness, and fracture toughness. The erosion damage created during testing has also been investigated using electron microscopy to observe the damage mechanism. The results of this study demonstrate that SPS coatings can outperform porous APS coatings in erosion resistance and could be considered a match for dense vertically cracked coatings. The SPS columnar coatings have shown a decreasing erosion rate with exposure time that suggest the influence of surface roughness on initial erosion behaviour.

  • 37. Das, D. K.
    et al.
    Roy, M.
    Singh, V.
    Joshi, S. V.
    Microstructural degradation of plain and platinum aluminide coatings on superalloy CM247 during isothermal oxidation1999Ingår i: Materials Science and Technology, Vol. 15, nr 10, s. 1199-1208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Isothermal oxidation at 1100°C of a high activity plain aluminide coating and a platinum aluminide coating, developed by the pack cementation technique, on cast nickel base superalloy CM247 has been carried out with the primary objective of systematically understanding the coating degradation process during oxidation. While the weight gains during oxidation for both plain aluminide and platinum aluminide coatings follow parabolic kinetics from the very beginning of oxidation exposure, the bare alloy was seen to exhibit a considerably long initial transient oxidation period (∼20 h), beyond which the parabolic law was followed. The parabolic rate constant for the platinum aluminide coating was found to be nearly two orders of magnitude lower than that for the plain aluminide coating. Alumina was identified as the only oxide phase that formed on both plain aluminide and platinum aluminide coatings during most of the oxidation exposure, although NiAl2O4 was also found in the case of the plain aluminide coating beyond ∼200 h. The oxide layer on the bare alloy, however, was found to consist of Al2O3, Cr2O3, and NiAl2O4. The microstructural degradation of both the plain aluminide and platinum aluminide coatings during oxidation was seen to occur in three distinct stages which, however, differed for each coating. This stagewise degradation, which involves final obliteration of the interdiffusion layer in each case, is discussed in detail. © 1999 IoM Communications Ltd.

  • 38. Das, D. K.
    et al.
    Singh, V.
    Joshi, S. V.
    Effect of Al content on microstructure and cyclic oxidation performance of Pt-aluminide coatings2002Ingår i: Oxidation of Metals, ISSN 0030-770X, E-ISSN 1573-4889, Vol. 57, nr 3-4, s. 245-266Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of Al content, i.e., the amount of Al picked up during aluminizing, on the microstructure and cyclic oxidation properties of Pt-aluminide coatings has been investigated. The cast Ni-base superalloy CM-247 was used as the substrate material and a single-step, high-activity pack aluminizing process was used to produce the Pt-aluminide coatings. The Al content of these coatings was varied by using packs with different compositions of the Al source. Pt-aluminide coatings having three different Al contents, namely 6.5, 16, and 21 mg cm-2, were evaluated for their cyclic oxidation resistance at 1200°C in air. It was found that the Pt-aluminide coatings, irrespective of their Al contents, evolve in the same manner during aluminizing and result in a three-layer structure with an outer PtAl2 + NiAl two-phase layer, an intermediate NiAl layer, and the inner interdiffusion layer. The stability of this three-layer coating structure over long periods of aluminizing, however, is dependent on the availability of Al from the pack during this period. Below a certain threshold Al availability, the two-phase outer layer transforms to a single-phase NiAl structure causing the coating to change from its three-layer structure to a two-layer one. Cyclic oxidation results indicate that, while a minimum Al content in Pt-aluminide coatings is essential for deriving the best oxidation performance, increasing the Al content beyond a certain level does not significantly enhance oxidation behavior. The effect of Al content on aspects, such as coating degradation and nature of coating-surface damage during cyclic oxidation, is also discussed.

  • 39. Das, D. K.
    et al.
    Singh, V.
    Joshi, S. V.
    Effect of prealuminizing diffusion treatment on microstructural evolution of high-activity pt-aluminide coatings2000Ingår i: Metallurgical and Materials Transactions. A, ISSN 1073-5623, E-ISSN 1543-1940, Vol. 31, nr 8, s. 2037-2047Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of prealuminizing (or prior) diffusion treatment on the evolution of Pt-aluminide coatings on the Ni-based superalloy CM-247 has been studied by using a single-step, high-activity aluminizing process. Coatings generated without any prior diffusion treatment, as well as those formed by adopting two extreme prior-diffusion schedules (at 850 °C for 0.5 hours and at 1034 °C for 5 hours), were investigated by analyzing the coating structures at various stages of aluminizing. When the dilution of the Pt layer, caused by its interdiffusion with the substrate during the prior diffusion treatment, is only marginal (as in the case of no prior diffusion and diffusion at 850 °C for 0.5 hours), the equilibrium Pt-aluminide coating structure evolves through the formation of two transient layers during the initial stages of aluminizing. In contrast, for diffusion at 1034 °C for 5 hours, which results in extensive dilution of the Pt layer, the two-phase equilibrium structure (PtAl2 in a matrix of NiAl) in the outer layer of the coating is found to develop during very early stages of aluminizing and remains unchanged, even over extended periods of aluminizing. Further, in the case of prior diffusion at 1034 °C for 5 hours, Pt is found to remain distributed to a greater extent over the entire thickness of the coating than in the cases of limited prior diffusion treatment. The present findings underline the significance of the nature of the prior-diffusion schedule on the microstructural evolution of Pt-aluminide coatings. It has also been found that a prealuminizing diffusion treatment is particularly important for Pt-aluminide coatings from the point of view of coating adhesion to the substrate.

  • 40. Das, D. K.
    et al.
    Srivastava, M. P.
    Joshi, S. V.
    Sivakumar, R.
    Scratch adhesion testing of plasma-sprayed yttria-stabilized zirconia coatings1991Ingår i: Surface and Coatings Technology, Vol. 46, nr 3, s. 331-345Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The suitability of scratch adhesion testing, usually used for determining the critical load for thin hard coatings like TiC and TiN, in characterizing plasma-sprayed yttria-stabilized zirconia coatings is demonstrated. The effects of loading rate and scratching speed on the critical load of these sprayed coatings were studied. Although some peculiarities in acoustic signal-load plot were observed at high values of loading rate and scratching speed, it was found that these intrinsic parameters, at low and medium values, do not have any prominent effect on the critical load. © 1991.

  • 41. DAS, D.K.
    et al.
    Singh, Vakil
    Joshi, Shrikant V.
    High temperature oxidation behaviour of directionally solidified nickel base superalloy CM–247LC2003Ingår i: Materials Science and Technology, ISSN 0267-0836, E-ISSN 1743-2847, Vol. 19, nr 6, s. 695-708Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present paper describes the isothermal and cyclic oxidation behaviour of the technologically important nickel base directionally solidified superalloy CM-247LC in air in the temperature range 1000-1200°C. This superalloy behaves as a transition nickel base alloy under isothermal oxidation conditions and exhibits a fairly long transient oxidation period (~20 h at 1100°C). Irrespective of the temperature of exposure and nature of oxidation (isothermal or cyclic), a composite oxide scale develops on CM-247LC. While the outer portion of the oxide scale consists of either spinel (NiAl2O4) or a mixture of spinel and NiO, depending on oxidation temperature, the inner portion is always constituted of alumina. Beyond the transient period, the alloy is found to follow parabolic oxidation kinetics. The oxide layer that forms is invariably very non-uniform in thickness, and is dispersed with two types of oxide particles. While tantalum rich oxide particles are found scattered in the outer zone of the oxide layer, hafnium rich oxide particles lie close to the oxide/metal interface. Results also reveal that the nature of oxidation associated with the CM-247LC superalloy causes entrapment of metal islands in the oxide layer.

  • 42. Das, O. K.
    et al.
    Singh, V.
    Joshi, S. V.
    Evolution of aluminide coating microstructure on nickel-base cast superalloy CM-247 in a single-step high-activity aluminizing process1998Ingår i: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 29, nr 8, s. 2173-2188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study deals with the aluminizing of a directionally cast Ni-base superalloy, namely CM-247, by a single-step process using a high-activity pack. It is observed that significant incorporation of Al into the substrate surface during aluminizing continues over a period of about 1 hour and is not restricted merely to the first few minutes, as reported in the literature. Based on the microstructural details of the coatings formed at various stages of aluminizing, it is concluded that the coating growth in the above process takes place primarily by inward Al diffusion initially, followed by an intermediate stage when the growth involves both inward Al and outward Ni diffusion. In the final stages, the outward diffusion of Ni dominates the coating formation process. The above mechanism of coating formation is different from the one that prevails in the conventional two-step high-activity coating process in that the reaction front for the formation of NiAl remains spatially stationary despite the outward diffusion of nickel during the intermediate stage. It is also shown in the present study that the content of the Al source in the pack affects the coating structure significantly. It is further demonstrated that the microstructure of the aluminide coatings depends not only on the amount of Al incorporated in the sample during aluminizing but also on the time over which the uptake of this Al takes place.

  • 43. Dhage, S. R.
    et al.
    Chandrasekhar, P. S.
    Chandrasekhar, S. B.
    Joshi, S. V.
    CIGS absorber layer by single-step non-vacuum intense pulsed light treatment of inkjet-printed film2014Ingår i: 2014 IEEE 40th Photovoltaic Specialist Conference, PVSC 2014, 2014, s. 1607-1610, artikel-id 6925227Konferensbidrag (Refereegranskat)
    Abstract [en]

    Non-vacuum processes are of great interest for development of low-cost chalcopyrite-based photovoltaic technologies. Apart from the expensive vacuum-based routes that are widely adopted, another negative feature of the popularly employed methods is the need for selenization treatment, which significantly impacts the microstructure of the absorber layer and, in turn, also determines the performance of the device. A novel process for preparation of Cu(In0.7Ga0.3)Se2 (CIGS) films from an ink constituted of CIGS nanoparticles utilizing a convenient intense pulsed light (IPL) treatment is investigated in the present study. Initially, a thorough optimization of ink formulation variables was carried out in order to make the CIGS ink suitable for ink jet printing. The home-made CIGS ink, comprising CIGS nanoparticles with appropriate additives, was then successfully deposited with a print head having 256 nozzles on Mo coated soda lime glass substrate. Subsequently, IPL was used to treat the printed CIGS ink. Post IPL treatment, a CIGS film retaining the chalcopyrite structure even after melting and recrystallization, with no secondary phase formation, was realized. The phase constitution, thickness and morphology of prepared films were determined using X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF) and field emission scanning electron microscopy (FESEM). The above non-vacuum, room temperature process not requiring any selenization treatment can have important implications in realization of cost-effective CIGS absorber layers.

  • 44. Dhage, S. R.
    et al.
    Tak, M.
    Joshi, S. V.
    Fabrication of CIGS thin film absorber by laser treatment of pre-deposited nano-ink precursor layer2014Ingår i: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 134, s. 302-305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A process to prepare Copper Indium Gallium Selenide (CIGS) absorber thin films by laser treatment of pre-deposited nano-inks has been investigated. Two approaches were followed, one using an ink of CIGS nanoparticles and other employing an ink comprising a mixture of a CIG metallic alloy and Se nanoparticles. Laser post treatment of the film applied with the CIGS ink was found to retain the chalcopyrite structure following melting and recrystallization, with no additional phases being generated during the process. Single-phase, highly crystalline CIGS thin films were also found to result from the ink made of CuIn0.7Ga0.3 and Se nanoparticles precursor following laser treatment. The CuIn0.7Ga 0.3Se2 thin films obtained in both cases were consistent with the initial constitution of the precursor materials used in terms of the Ga/(Ga+In) ratio. The prepared films were comprehensively characterized using XRD, SEM-EDS and XRF. Results reveal that the above non-vacuum approach obviating the need for a selenization step is simple, quick and expected to have a large impact on the overall process economics for fabrication of CIGS thin film solar cells. © 2014 Elsevier B.V.

  • 45. Dineshram, R.
    et al.
    Subasri, R.
    Somaraju, K. R. C.
    Jayaraj, K.
    Vedaprakash, L.
    Ratnam, K.
    Joshi, S. V.
    Venkatesan, R.
    Biofouling studies on nanoparticle-based metal oxide coatings on glass coupons exposed to marine environment2009Ingår i: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 74, nr 1, s. 75-83Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Titania, niobia and silica coatings, derived from their respective nanoparticle dispersions or sols and fabricated on soda lime glass substrates were subjected to field testing in marine environment for anti-macrofouling applications for marine optical instruments. Settlement and enumeration of macrofouling organisms like barnacles, hydroides and oysters on these nanoparticle-based metal oxide coatings subjected to different heat treatments up to 400 degrees C were periodically monitored for a period of 15 days. The differences observed in the antifouling behaviour between the coated and uncoated substrates are discussed based on the solar ultraviolet light induced photocatalytic activities as well as hydrophilicities of the coatings in case of titania and niobia coatings and the inherent hydrophilicity in the case of silica coating. The effect of heat treatment on the photocatalytic activity of the coatings is also discussed. (C) 2009 Elsevier B.V. All rights reserved.

  • 46. Dom, R.
    et al.
    Kumar, G. S.
    Hebalkar, N. Y.
    Joshi, S. V.
    Borse, P. H.
    Eco-friendly ferrite nanocomposite photoelectrode for improved solar hydrogen generation2013Ingår i: RSC Advances, E-ISSN 2046-2069, Vol. 3, nr 35, s. 15217-15224Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    For the first time, a ferrite nanocomposite photoelectrode (FNCP) has been fabricated and investigated for photoelectrochemical hydrogen production from water under simulated solar light. The ZnFe2O4:Fe 2O3 nanocomposite photoanode has been fabricated via a single step methodology using a novel approach involving the solution precursor plasma spraying technique. The FNCP is achieved by optimal phase formation during the deposition of the ferrite film (∼10 μm) over a stainless steel substrate. It exhibits an enhanced photoactivity 6 times higher compared to pure ZnFe2O4 (ZFO), under simulated-solar (AM1.5 G) illumination. Its Mott-Schottky characterization reveals an n-type semiconducting behaviour, indicating an order of magnitude higher donor density (Nd ∼ 1017 cm-3) than the pure phase ZnFe2O4 electrode. It also exhibits a low band gap of 1.94 eV demonstrating that it can more efficiently absorb visible light photons than other systems comprising of bare zinc ferrite or iron oxide. The FNCP yielded a solar-to-hydrogen conversion efficiency of 1.25% under simulated solar radiation (AM1.5 G) with a hydrogen evolution rate of 99 μmol h-1. Electrochemical impedance spectroscopy of the FNCP revealed a significantly improved charge transfer characteristic compared to ZnFe2O 4. An enhanced photoactivity for the oxidation of water from the FNCP is attributed to its improved optical absorption and better charge transfer properties induced by the existence of Fe2O3 in ZnFe 2O4. © The Royal Society of Chemistry 2013.

  • 47. Dom, R.
    et al.
    Kumar, G. S.
    Kim, H. G.
    Joshi, S. V.
    Chary, S.
    Borse, P. H.
    Design and development of ferrite composite film electrode for photoelectrochemical energy application2014Ingår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 781, s. 45-61Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Development of efficient photoanodes for water splitting under solar light is desirable to surmount the possible fuel crisis in future. Ferrite systems, with their excellent visible light absorption capability, stability, non-toxicity, cost-effectiveness and abundance, are being preferred to titanates, niobates and sulfides. The present work briefly reviews the modified form of ferrites. Additionally, ZnFe2O4 an n-type semiconductor with the low band gap (~1.9eV) has been considered as special case of visible light PEC application. The work further emphasizes on the utilization of solution processed techniques to develop the ferrite photoanodes. The tuning of photoanode properties by virtue of electrode fabrication parameters say deposition parameters viz., precursor concentration, pH, stoichiometry has been reviewed and discussed. © (2014) Trans Tech Publications, Switzerland.

  • 48. Dom, R.
    et al.
    Sivakumar, G.
    Hebalkar, N. Y.
    Joshi, S. V.
    Borse, P. H.
    Deposition of nanostructured photocatalytic zinc ferrite films using solution precursor plasma spraying2012Ingår i: Materials research bulletin, ISSN 0025-5408, E-ISSN 1873-4227, Vol. 47, nr 3, s. 562-570Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Deposition of pure spinel phase, photocatalytic zinc ferrite films on SS-304 substrates by solution precursor plasma spraying (SPPS) has been demonstrated for the first time. Deposition parameters such as precursor solution pH, concentration, film thickness, plasma power and gun-substrate distance were found to control physico-chemical properties of the film, with respect to their crystallinity, phase purity, and morphology. Alkaline precursor conditions (7 &lt; pH ≤ 10) were found to favor oxide film formation. The nanostructured films produced under optimized conditions, with 500 mM solution at pH ∼ 8.0, yielded pure cubic phase ZnFe 2O 4 film. Very high/low precursor concentrations yielded mixed phase, less adherent, and highly inhomogeneous thin films. Desired spinel phase was achieved in as-deposited condition under appropriately controlled spray conditions and exhibited a band gap of ∼1.9 eV. The highly porous nature of the films favored its photocatalytic performance as indicated by methylene blue de-coloration under solar radiation. These immobilized films display good potential for visible light photocatalytic applications. © 2012 Elsevier Ltd. All rights reserved.

  • 49.
    Dom, Rekha
    et al.
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur PO, Hyderabad, Telangana (IND).
    Govindarajan, Sivakumar
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur PO, Hyderabad, Telangana (IND).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Borse, Pramod H.
    International Advanced Research Centre for Powder Metallurgy and New Materials, Balapur PO, Hyderabad, Telangana (IND).
    A solar-responsive zinc oxide photoanode for solar-photon-harvester photoelectrochemical (PEC) cells2020Ingår i: Nanoscale Advances, E-ISSN 2516-0230, Vol. 2, nr 8, s. 3350-3357Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A highly efficient, nanostructured, solar-responsive zinc-oxide (SRZO) photoanode has been achieved by utilization of a versatile solution precursor plasma spray (SPPS) deposition technique. For the first time, it is demonstrated that a front-illumination type SRZO photo-anode fabricated with a ZnO/stainless steel (SS-304) configuration can generate an enhanced photo-electrochemical (PEC) current of 390 mA cm(-2), under solar radiation from a solar simulator with an AM1.5 global filter (similar to 1 sun). The SRZO electrode displayed a solar-to-hydrogen (STH) conversion efficiency of 2.32% when investigated for H-2 evolution in a PEC cell. These electrodes exhibited a maximum peak efficiency of 86% using 320 nm photons during incident photon-to-current conversion efficiency measurement. Interestingly, the film lattice of SRZO showed a significant red-shift of 0.37 eV in the ZnO band gap thereby providing solar photon absorptivity to SRZO. Further, an enhanced charge transport property by virtue of increased donor density (similar to 4.11 x 10(17) cm(-3)) has been observed, which is higher by an order of magnitude than that of its bulk counterpart. Efficient optical absorption of solar photons and higher donor-density of SRZO have been thus attributed to its superior PEC performance.

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  • 50.
    Eklund, Johan
    et al.
    Chalmers University of Technology, Energy and Materials, Department of Chemistry and Chemical Engineering, Göteborg, 412 96, Sweden.
    Phother, J.
    Chalmers University of Technology, Energy and Materials, Department of Chemistry and Chemical Engineering, Göteborg, 412 96, Sweden.
    Sadeghi, Esmaeil
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT).
    Joshi, Shrikant V.
    Högskolan Väst, Institutionen för ingenjörsvetenskap, Forskningsmiljön produktionsteknik(PTW).
    Liske, Jesper
    Chalmers University of Technology, Energy and Materials, Department of Chemistry and Chemical Engineering, Göteborg, 412 96, Sweden.
    High-Temperature Corrosion of HVAF-Sprayed Ni-Based Coatings for Boiler Applications2019Ingår i: Oxidation of Metals, ISSN 0030-770X, E-ISSN 1573-4889, Vol. 91, nr 5-6, s. 729-747Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present study investigates the initial corrosion behaviour of HVAF-sprayed NiCr, NiAl and NiCrAlY coatings in two different environments, O 2 + H 2 O and O 2 + H 2 O + KCl at 600 °C for up to 168 h in order to evaluate the possibility of utilizing such coatings in biomass- and waste-fired boilers. SEM/EDX analysis showed that all coatings displayed a protective behaviour in O 2 + H 2 O. Upon addition of KCl (O 2 + H 2 O + KCl), the corrosion behaviour of the NiCr coating drastically changed as it formed a thick oxide layer and displayed major chlorine diffusion down to the substrate. The NiCrAlY coating displayed a significantly better corrosion resistance with only minor oxide formation. The NiAl coating exhibited a protective behaviour similar to when exposed in the absence of KCl indicating that a thin protective oxide has formed on the coating surface. The performance of the NiAl and NiCrAlY coatings is promising for future studies with long-term exposures in more corrosive environments such as in a biomass- and waste-fired boiler. © 2019, The Author(s).

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