Analysis of damage evolution in thick ceramic coatings

This paper analyses the damage evolution process in thick ceramic coatings on cylindrical bodies exposed to uniform heating for two cases of the substrate material under conditions of plane strain. Alumina coatings with three different types of the initial through-thickness distribution of manufacture-induced porosity (uniform as well as with increasing and decreasing porosity levels with the distance from the interface) are studied. The analysis is based on a general computational scheme to determine damage evolution parameters, which incorporates a solution of the appropriate problem of thermoelasticity. It is shown that the type of the substrate interplays with the coating's thickness in its influence upon the character and rate of damage accumulation in coatings. A number of other important features of the damage evolution process in thick ceramic coatings linked to the coating's thickness are also revealed.