Comparison of the developed thermal stresses in Al2O3-SG, ZrO2-12%Si+Al and ZrO2-SG coating systems subjected to thermal loading

Abstract

In this investigation, thermal and structure finite element analysis has been employed to analyse the thermal stresses developed in Al2O3-SG, ZrO2-12%Si + Al and ZrO2-SG coatings subjected to thermal loading. Systems with 0.4 mm coating thickness and 4 mm substrate material thickness were modelled. Zirconia-spherical cast iron (SG) coatings with NiAl, NiCrAlY and NiCoCrAlY interlayers were also modelled. Nominal and shear stresses at the critical interface regions (film/interlayer/substrate) were obtained. The results showed that the lowest stress levels are in ZrO2-SG coatings. Furthermore, the interlayer thickness and material combinations have a significant influence on the level of the developed thermal stresses. It is also concluded that the finite element technique can be used to optimise the design and the processing of ceramic coatings. (C) 1999 Elsevier Science Ltd. All rights reserved.