Influence of interlayer material and geometry on stress levels in MgO.ZrO2-GG coatings subjected to thermal shock

In this paper, coupled (thermal and structure) finite element analysis has been employed to analyze the influence of interlayer material and geometry in MgO.ZrO2-GG coatings subjected to thermal loading. coatings with NiAl, NiCrA/Y, NiCoCrAlY interlayers and with different combinations of these interlayer materials were modeled. All models had a coating to substrate thickness ratio of 1:10 and with different interlayer thickness of 0.1, 0.2 and 0.3 mm. Nominal and shear stresses at the critical interface regions (film/interlayer/substrate) were obtained and compared. The results showed that the interlayer thickness and material combinations have a significant influence on the level of the developed thermal stresses. It was also concluded that the finite element technique can be used to optimize the design and the processing of ceramic coatings. (C) 1997 Elsevier Science Lid. All rights reserved.