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Ganvir, A., Björklund, S., Yao, Y., Vadali, S. V., Klement, U. & Joshi, S. V. (2019). A facile approach to deposit graphenaceous composite coatings by suspension plasma spraying. Coatings, 9(3), Article ID 171.
Open this publication in new window or tab >>A facile approach to deposit graphenaceous composite coatings by suspension plasma spraying
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2019 (English)In: Coatings, ISSN 2079-6412, Vol. 9, no 3, article id 171Article in journal (Refereed) Published
Abstract [en]

This paper demonstrates, for the first time ever, the deposition of graphenaceous composite coatings using an easy, yet robust, suspension plasma spraying (SPS) process. As a case study, a composite coating comprising 8 wt.% of yttria-stabilized-zirconia (8YSZ) and reinforced with graphene oxide (GO) was deposited on a steel substrate. The coatings were sprayed using an 8YSZ-GO mixed suspension with varied plasma spray parameters. Establishing the possibility of retaining the graphene in a ceramic matrix using SPS was of specific interest. Electron microscopy and Raman spectroscopy confirmed the presence of graphenaceous material distributed throughout the coating in the 8YSZ matrix. The experimental results discussed in this work confirm that SPS is an immensely attractive pathway to incorporate a graphenaceous material into virtually any matrix material and can potentially have major implications in enabling the deposition of large-area graphene-containing coatings for diverse functional applications. © 2019 by the authors.

Place, publisher, year, edition, pages
MDPI AG, 2019
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-13737 (URN)10.3390/coatings9030171 (DOI)000465608700002 ()2-s2.0-85062495390 (Scopus ID)
Available from: 2019-03-21 Created: 2019-03-21 Last updated: 2019-05-10
Hameed, P., Gopal, V., Björklund, S., Ganvir, A., Sen, D., Markocsan, N. & Manivasagam, G. (2019). Axial Suspension Plasma Spraying: An ultimate technique to tailor Ti6Al4V surface with HAp for orthopaedic applications. Colloids and Surfaces B: Biointerfaces, 173, 806-815
Open this publication in new window or tab >>Axial Suspension Plasma Spraying: An ultimate technique to tailor Ti6Al4V surface with HAp for orthopaedic applications
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2019 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 173, p. 806-815Article in journal (Refereed) Published
Abstract [en]

Dissolution of atmospheric plasma sprayed (APS) hydroxyapatite (HAp) coatings on Ti-6Al-4 V medical implants have always been a challenge to overcome in the field of biomedical industry. In the present work, an attempt has been made to develop a HAp coating using a novel thermal spray process called axial suspension plasma spraying (SPS), which leads to thin adherent coatings. Two HAp coatings fabricated by APS (P1 and P2) and four SPS HAp coatings (S1, S2, S3 and S4) produced with varying spraying parameters were characterized in terms of (1) microstructure, porosity, hardness, adhesion strength, contact angle and phase purity; (2) corrosion resistance in 10% Fetal bovine serum (FBS); (3) in-vitro cell adherence and cell viability using human umbilical cord blood-derived mesenchymal stem cells (hMSCs). Amongst different APS and SPS coatings, P1 and S3 exhibited superior properties. S3 coating developed using SPS exhibited 1.3 times higher adhesion strength when compared to APS coating (P1) and 9.5 times higher corrosion resistance than P1. In addition, both S3 and P1 exhibited comparatively higher biocompatibility as evidenced by the presence of more than 92% viable hMSCs. © 2018 Elsevier B.V.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Adhesion; Aluminum alloys; Aluminum coatings; Aluminum corrosion; Atmospheric corrosion; Biocompatibility; Bond strength (materials); Cell adhesion; Cell culture; Contact angle; Corrosion resistance; Corrosion resistant coatings; Corrosive effects; Hydroxyapatite; Mammals; Phase shifters; Plasma jets; Sprayed coatings; Stem cells; Ternary alloys; Thermal spraying; Titanium alloys; Vanadium alloys, Atmospheric plasma spraying; Corrosion studies; hMSCs; Suspension plasma spraying; Ti-6 Al-4 V, Plasma spraying
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-13115 (URN)10.1016/j.colsurfb.2018.10.071 (DOI)000454377300095 ()30551296 (PubMedID)2-s2.0-85055725408 (Scopus ID)
Note

Available online 26 October 2018.

Available from: 2018-11-12 Created: 2018-11-12 Last updated: 2019-01-18Bibliographically approved
Ganvir, A., Calinas, R. F., Markocsan, N., Curry, N. & Joshi, S. V. (2019). Experimental visualization of microstructure evolution during suspension plasma spraying of thermal barrier coatings. Journal of the European Ceramic Society, 39(2-3), 470-481
Open this publication in new window or tab >>Experimental visualization of microstructure evolution during suspension plasma spraying of thermal barrier coatings
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2019 (English)In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 39, no 2-3, p. 470-481Article in journal (Refereed) Published
Abstract [en]

This paper investigates the evolution of microstructure of thermal barrier coatings (TBCs) produced by suspension plasma spraying (SPS) through a careful experimental study. Understanding the influence of different suspension characteristics such as type of solvent, solid load content and median particle size on the ensuing TBC microstructure, as well as visualizing the early stages of coating build-up leading to formation of a columnar microstructure or otherwise, was of specific interest. Several SPS TBCs with different suspensions were deposited under identical conditions (same substrate, bond coat and plasma spray parameters). The experimental study clearly revealed the important role of suspension characteristics, namely surface tension, density and viscosity, on the final microstructure, with study of its progressive evolution providing invaluable insights. Variations in suspension properties manifest in the form of differences in droplet momentum and trajectory, which are found to be key determinants governing the resulting microstructure (e.g., lamellar/vertically cracked or columnar).

Keywords
Suspension plasma spraying, Thermal barrier coatings, Droplet momentum, Columnar microstructure, Microstructure evolution
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering; Production Technology
Identifiers
urn:nbn:se:hv:diva-12948 (URN)10.1016/j.jeurceramsoc.2018.09.023 (DOI)000450379400042 ()2-s2.0-85053889817 (Scopus ID)
Funder
Region Västra Götaland, RUN 612-0974-13
Available from: 2018-10-26 Created: 2018-10-26 Last updated: 2018-12-20Bibliographically approved
Algenaid, W., Ganvir, A., Calinas, R. F., Varghese, J., Rajulapati, K. V. & Joshi, S. V. (2019). Influence of microstructure on the erosion behaviour of suspension plasma sprayed thermal barrier coatings. Surface & Coatings Technology, 375, 86-99
Open this publication in new window or tab >>Influence of microstructure on the erosion behaviour of suspension plasma sprayed thermal barrier coatings
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2019 (English)In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 375, p. 86-99Article in journal (Refereed) Published
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.

Keywords
Engines; Erosion; Fracture toughness; Microstructure; Offshore oil well production; Plasma jets; Porosity; Silicon compounds; Sprayed coatings; Thermal barrier coatings; Thermal insulation, Atmospheric plasmas; Coating microstructures; Columnar microstructures; Physical vapor deposited; Plasma-sprayed thermal barrier coating; Suspension plasma spraying; Thermal barrier coating (TBCs); Turbine efficiency, Plasma spraying
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-14462 (URN)10.1016/j.surfcoat.2019.06.075 (DOI)2-s2.0-85068658494 (Scopus ID)
Available from: 2019-10-01 Created: 2019-10-01 Last updated: 2019-10-03
Ganvir, A. (2018). Design of Suspension Plasma Sprayed Thermal Barrier Coatings. (Doctoral dissertation). Trollhättan: University West
Open this publication in new window or tab >>Design of Suspension Plasma Sprayed Thermal Barrier Coatings
2018 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Thermal barrier coatings (TBCs) are widely used on gas turbine components to provide thermal insulation, which in combination with advanced cooling, can enable the gas turbine to operate at significantly higher temperatures even above the melting temperature of the metallic components. There is a permanent need,mainly due to environmental reasons, to increase the combustion temperature inturbines, hence new TBC solutions are needed. By using a liquid feedstock in thermal spraying, new types of TBCs can be produced. Suspension plasma/flame or solution precursor plasma spraying are examples of techniques that can be utilized for liquid feedstock thermal spraying. This approach of using suspension and solution feedstock, which is an alternative to the conventional solid powder feedstock spraying, is gaining increasing research interest since it has been shown to be capable of producing coatings withsuperior performance. The objective of this research work was to identify relationships between process parameters, coating microstructure, thermal conductivity and lifetime in suspension plasma sprayed TBCs. A further objective was to utilize these relationships to enable tailoring of the TBC microstructure for superior performance compared to state-of-the-art TBC used in industry today, i.e. solid feedstock plasma sprayed TBCs. Different spraying techniques, namely suspension high velocity oxy fuel, solution precursor plasma and suspension plasma spraying (with axial and radial feeding) were explored and compared to solid feedstock plasma spraying. A variety of microstructures, such as highly porous, vertically cracked and columnar, were produced and investigated. It was shown that there are strong relationships between microstructure, thermo-mechanical properties and performance of the coatings. Specifically, axial suspension plasma spraying wasshown as a very promising technique to produce various microstructures as wellas highly durable coatings. Based on the experimental results, a tailored columnar microstructure design for a superior TBC performance is also proposed.

Place, publisher, year, edition, pages
Trollhättan: University West, 2018. p. 96
Series
PhD Thesis: University West ; 20
Keywords
Microstructure; Thermal Barrier Coatings; Axial Injection; Suspension Plasma Spraying; Porosity; Thermal Conductivity; Fracture Toughness; Lifetime
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology; ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-12336 (URN)978-91-87531-92-7 (ISBN)978-91-87531-91-0 (ISBN)
Public defence
2018-06-15, F104, University West, Trollhättan, 10:15 (English)
Opponent
Supervisors
Available from: 2018-05-25 Created: 2018-05-23 Last updated: 2018-05-25
Ganvir, A., Vaidhyanathan, V., Markocsan, N., Gupta, M. K., Pala, Z. & Lukac, F. (2018). Failure analysis of thermally cycled columnar thermal barrier coatings produced by high-velocity-air fuel and axial-suspension-plasma spraying: A design perspective. Ceramics International, 44(3), 3161-3172
Open this publication in new window or tab >>Failure analysis of thermally cycled columnar thermal barrier coatings produced by high-velocity-air fuel and axial-suspension-plasma spraying: A design perspective
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2018 (English)In: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 44, no 3, p. 3161-3172Article in journal (Refereed) Published
Abstract [en]

Axial-suspension-plasma spraying (ASPS) is a fairly recent thermal spray technology which enables production of ceramic top coats in TBCs, incorporating simultaneously the properties of both the conventional-plasma sprayed (highly insulating porous structures) and electron-beam-physical-vapor-deposited (strain-tolerant columnar structures) top coats. TBCs are required to insulate the hot components in a gas turbine engine against high temperature and harsh operating conditions. Periodic heating and cooling of turbine engines during operation can create severe thermal cyclic fatigue conditions which can degrade the performance of these coatings eventually leading to the failure. An in-depth experimental investigation was performed to understand the failure behavior of columnar TBCs subjected to thermal cyclic fatigue (TCF) test at 1100 C. The study revealed that the TCF performance was influenced to an extent, by the top coat microstructure, but was primarily affected by the severity of thermally grown oxide (TGO) growth at the bond coat-top coat interface. Mixed failure modes comprising crack propagation through the bond coat-TGO interface, through TGO and within the top coat were identified. Based on the analysis of the experimental results and thorough discussion a novel design of microstructure for the high TCF performance columnar TBC is proposed. © 2017 Elsevier Ltd and Techna Group S.r.l.

Keywords
Air; Coatings; Engines; Gas turbines; Microstructure; Plasma jets; Plasma spraying; Sprayed coatings; Structural design; Suspensions (components); Thermal spraying, Columnar structures; Experimental investigations; High velocity air fuels; Physical vapor deposited; Suspension plasma spraying; Thermal cyclic fatigue; Thermal spray technology; Thermally grown oxide, Thermal barrier coatings
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-11920 (URN)10.1016/j.ceramint.2017.11.084 (DOI)000423891900070 ()2-s2.0-85034822127 (Scopus ID)
Funder
Region Västra Götaland, RUN 612-0974-13
Available from: 2017-12-13 Created: 2017-12-13 Last updated: 2019-05-28Bibliographically approved
Ganvir, A., Joshi, S. V., Markocsan, N. & Vassen, R. (2018). Tailoring columnar microstructure of axial suspension plasma sprayed TBCs for superior thermal shock performance. Materials & design, 144, 192-208
Open this publication in new window or tab >>Tailoring columnar microstructure of axial suspension plasma sprayed TBCs for superior thermal shock performance
2018 (English)In: Materials & design, ISSN 0264-1275, E-ISSN 1873-4197, Vol. 144, p. 192-208Article in journal (Refereed) Published
Abstract [en]

This paper investigates the thermal shock behavior of thermal barrier coatings (TBCs) produced by axial suspension plasma spraying (ASPS). TBCs with different columnar microstructures were subjected to cyclic thermal shock testing in a burner rig. Failure analysis of these TBCs revealed a clear relationship between lifetime and porosity. However, tailoring the microstructure of these TBCs for enhanced durability is challenging due to their inherently wide pore size distribution (ranging from few nanometers up to few tens of micrometers). This study reveals that pores with different length scales play varying roles in influencing TBC durability. Fracture toughness shows a strong correlation with the lifetime of various ASPS TBCs and is found to be the prominent life determining factor. Based on the results, an understanding-based design philosophy for tailoring of the columnar microstructure of ASPS TBCs for enhanced durability under cyclic thermal shock loading is proposed. © 2018 The Authors

Keywords
Coatings; Durability; Fracture toughness; Microstructure; Plasma jets; Plasma spraying; Pore size; Shock testing; Size distribution; Thermal shock; Thermal spraying, Columnar microstructures; Cyclic thermal shocks; Design philosophy; Different length scale; Strong correlation; Superior performance; Suspension plasma spraying; Thermal barrier coating (TBCs), Thermal barrier coatings
National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-12192 (URN)10.1016/j.matdes.2018.02.011 (DOI)000427609400017 ()2-s2.0-85042178578 (Scopus ID)
Funder
Region Västra Götaland, RUN 612-0974-13Knowledge Foundation, DNr 20140130
Available from: 2018-03-05 Created: 2018-03-05 Last updated: 2019-05-28Bibliographically approved
Ekberg, J., Ganvir, A., Klement, U., Creci, S. & Nordstierna, L. (2018). The Influence of Heat Treatments on the Porosity of Suspension Plasma-Sprayed Yttria-Stabilized Zirconia Coatings. Journal of thermal spray technology (Print), 27(3), 391-401
Open this publication in new window or tab >>The Influence of Heat Treatments on the Porosity of Suspension Plasma-Sprayed Yttria-Stabilized Zirconia Coatings
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2018 (English)In: Journal of thermal spray technology (Print), ISSN 1059-9630, E-ISSN 1544-1016, Vol. 27, no 3, p. 391-401Article in journal (Refereed) Published
Abstract [en]

Suspension plasma-sprayed coatings are produced using fine-grained feedstock. This allows to control the porosity and to achieve low thermal conductivity which makes the coatings attractive as topcoats in thermal barrier coatings (TBCs). Used in gas turbine applications, TBCs are exposed to high temperature exhaust gases which lead to microstructure alterations. In order to obtain coatings with optimized thermomechanical properties, microstructure alterations like closing of pores and opening of cracks have to be taken into account. Hence, in this study, TBC topcoats consisting of 4 mol.% yttria-stabilized zirconia were heat-treated in air at 1150 °C and thereafter the coating porosity was investigated using image analysis (IA) and nuclear magnetic resonance (NMR) cryoporometry. Both IA and NMR cryoporometry showed that the porosity changed as a result of the heat treatment for all investigated coatings. In fact, both techniques showed that the fine porosity decreased as a result of the heat treatment, while IA also showed an increase in the coarse porosity. When studying the coatings using scanning electron microscopy, it was noticed that finer pores and cracks disappeared and larger pores grew slightly and achieved a more distinct shape as the material seemed to become more compact.

National Category
Manufacturing, Surface and Joining Technology
Research subject
ENGINEERING, Manufacturing and materials engineering
Identifiers
urn:nbn:se:hv:diva-11994 (URN)10.1007/s11666-017-0682-y (DOI)000425622500013 ()2-s2.0-85040077858 (Scopus ID)
Funder
Region Västra Götaland
Note

First Online: 04 January 2018

Available from: 2018-01-16 Created: 2018-01-16 Last updated: 2019-01-23Bibliographically approved
Klement, U., Ekberg, J. & Ganvir, A. (2017). EBSD Analysis and Assessment of Porosity in Thermal Barrier Coatings Produced by Axial Suspension Plasma Spraying (ASPS). In: C. Sommitsch, M. Ionescu, B. Mishra, E. Kozeschnik och T. Chandra (Ed.), Materials Science Forum, THERMEC 2016: Chapter 2: Contributed Papers. Paper presented at THERMEC'2016, International Conference of Processing & Manufacturing of Advanced Materials: Processing, Fabrication, Properties, Applications, Graz, Austria, May 29- June 3, 2016 (pp. 972-977). Trans Tech Publications, 879
Open this publication in new window or tab >>EBSD Analysis and Assessment of Porosity in Thermal Barrier Coatings Produced by Axial Suspension Plasma Spraying (ASPS)
2017 (English)In: Materials Science Forum, THERMEC 2016: Chapter 2: Contributed Papers / [ed] C. Sommitsch, M. Ionescu, B. Mishra, E. Kozeschnik och T. Chandra, Trans Tech Publications, 2017, Vol. 879, p. 972-977Conference paper, Published paper (Refereed)
Abstract [en]

Axial suspension plasma spraying (ASPS) is a relatively new, innovative spraying technique which has produced thermal barrier coatings (TBCs) with attractive properties such as high durability and low thermal conductivity. Using a suspension, it is possible to spray with finer powder particles resulting in coatings that have a columnar microstructure and contain a wide range of pore sizes, both nm-and μm-sized pores. To optimize the thermal properties and to maintain them during service of the components, it will be important to design TBCs with optimal porosity. Hence, an important part in the assessment of ASPS coatings is therefore the characterization of the microstructure and how it is build up, and the determination of porosity. Both aspects are addressed by performing measurement on splats and ASPS-coating using electron backscatter diffraction (EBSD) technique and by measuring porosity by Mercury Intrusion Porosimetry (MIP).

Place, publisher, year, edition, pages
Trans Tech Publications, 2017
Keywords
Axial Suspension Plasma Spraying, Electron Backscatter Diffraction (EBSD), Mercury Intrusion Porosimetry, Porosity, Scanning Electron Microscopy (SEM), Thermal Barrier Coatings (TBCs), XRM
National Category
Manufacturing, Surface and Joining Technology
Identifiers
urn:nbn:se:hv:diva-10328 (URN)10.4028/www.scientific.net/MSF.879.972 (DOI)2-s2.0-85000428327 (Scopus ID)
Conference
THERMEC'2016, International Conference of Processing & Manufacturing of Advanced Materials: Processing, Fabrication, Properties, Applications, Graz, Austria, May 29- June 3, 2016
Available from: 2016-12-16 Created: 2016-12-16 Last updated: 2016-12-20Bibliographically approved
Ganvir, A., Markocsan, N. & Joshi, S. V. (2017). Influence of Isothermal Heat Treatment on Porosity and Crystallite Size in Axial Suspension Plasma Sprayed Thermal Barrier Coatings for Gas Turbine Applications. Coatings, 7(1), 1-14, Article ID 4.
Open this publication in new window or tab >>Influence of Isothermal Heat Treatment on Porosity and Crystallite Size in Axial Suspension Plasma Sprayed Thermal Barrier Coatings for Gas Turbine Applications
2017 (English)In: Coatings, ISSN 2079-6412, Vol. 7, no 1, p. 1-14, article id 4Article in journal (Refereed) Published
Abstract [en]

xial suspension plasma spraying (ASPS) is an advanced thermal spraying technique, which enables the creation of specific microstructures in thermal barrier coatings (TBCs) used for gas turbine applications. However, the widely varying dimensional scale of pores, ranging from a few nanometers to a few tenths of micrometers, makes it difficult to experimentally measure and analyze porosity in SPS coatings and correlate it with thermal conductivity or other functional characteristics of the TBCs. In this work, an image analysis technique carried out at two distinct magnifications, i.e., low (500×) and high (10,000×), was adopted to analyze the wide range of porosity. Isothermal heat treatment of five different coatings was performed at 1150 °C for 200 h under a controlled atmosphere. Significant microstructural changes, such as inter-columnar spacing widening or coalescence of pores (pore coarsening), closure or densification of pores (sintering) and crystallite size growth, were noticed in all the coatings. The noted changes in thermal conductivity of the coatings following isothermal heat treatment are attributable to sintering, crystallite size growth and pore coarsening

Keywords
axial suspension plasma spraying; thermal barrier coatings; sintering; pore coarsening; nano-sized pores; crystallite size growth; thermal conductivity
National Category
Manufacturing, Surface and Joining Technology
Research subject
Production Technology
Identifiers
urn:nbn:se:hv:diva-10505 (URN)10.3390/coatings7010004 (DOI)000395504700004 ()
Available from: 2017-01-09 Created: 2017-01-09 Last updated: 2019-06-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1897-0171

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