Effect of columnar cracks and dense layer in suspension plasma sprayed thermal barrier coatings on the coating stresses under thermal shock loadings: A modelling approach
2016 (English)In: The 7th International Swedish Production Symposium, SPS16, Conference Proceedings: 25th – 27th of October 2016, Lund: Swedish Production Academy , 2016, 1-8 p.Conference paper (Refereed)
Suspension Plasma Spraying (SPS) has been shown as a promising process to produce porous columnar strain tolerant coatings for thermal barrier coating applications in gas turbine engines. However, the highly porous structure is vulnerable to crack propagation, especially near the top coat-bond coat interface, where high stresses are generated due to thermal shock conditions that occur during engine operation. These stresses directly influence the coating lifetime. A topcoat layer with high toughness near the top coat-bond coat interface could thus be beneficial to withstand the stresses. In this work, a bilayer coating system was fabricated by SPS using yttria stabilised zirconia. The bilayer coating consisted of a dense topcoat layer near the top coat-bond coat interface which could provide the necessary toughness followed by a porous columnar structured layer which contains columnar cracks which could provide the necessary strain tolerance. The objective of this work is to study the effect of the columnar/vertical crack features on the generated stresses in the thermal barrier coating during thermal cyclic loading. A finite element modelling approach has been used for this purpose. The results show that the bilayer coating structure reduces the thermally induced stresses and could thus increase the lifetime.
Place, publisher, year, edition, pages
Lund: Swedish Production Academy , 2016. 1-8 p.
Thermal barrier coatings, Suspension Plasma Spraying, bilayer coating system, finite element modelling, stresses, lifetime
Manufacturing, Surface and Joining Technology
Research subject ENGINEERING, Manufacturing and materials engineering
IdentifiersURN: urn:nbn:se:hv:diva-10244OAI: oai:DiVA.org:hv-10244DiVA: diva2:1052934
7th International Swedish Production Symposium, SPS16, Lund, Sweden, October 25–27, 2016