Bond Coat Influence on TBC Life
(English)Manuscript (preprint) (Other academic)
In the present study the influence of bond coat composition and coating process on thermal barrier coating (TBC) life has been evaluated. Six different coatings have been subjected to thermal cycling between 100 and 1100°C. After this the different systems have been characterised by light microscopy and SEM-EDS. Various commercial bond coats have been applied on one substrate material (Haynes alloy 230). The total fatigue life of the different TBC systems varies with 30% what is believed to be influenced by diffusion and oxidation phenomena in the bond coat. It is found that when the aluminium concentration is decreased phases other than alumina form at the top coat I bond coat interface. Oxides formed during later stages of the thermal cyclic test are rich in nickel, cobalt and chromium and the results can be interpreted as formation of nickel-, chromium- or spinel oxides. The reason for TBC failure is coupled to aluminium depletion, which here is believed to be due to inward diffusion and formation of thermally grown oxides (TGO) at the ceramic top coat (TC) metallic bond coat (BC) interface as well as growth of internal oxides in the bond coat.
thermal barrier coating, NiCoCrAIY, CoNiCrAIY, alumina, thermal fatigue, oxide growth, interdiffusion
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-102046OAI: oai:DiVA.org:liu-102046DiVA: diva2:667997