Analytical Modeling of Oxide Thickness Effects on Residual Stresses in Thermal Barrier Coatings
C H. Hsueh, Lin-Sien H. Lum
The effects of the thickness of the thermally grown oxide on residual thermal stresses in a plasma-sprayed thermal barrier coating were numerically simulated in Part I. In the tip region of a convex asperity, the residual stress normal to the interface, (alpha)y, in the ceramic top coat is tensile for a thin oxide but becomes compressive for a thick oxide. In the tip region of a concave asperity, (alpha)y in the ceramic top coat is compressive for a thin oxide and becomes less compressive for a thick oxide. The physical meaning of the above trend was qualitatively interpreted in the present study by using an analytical model of three concentric circles.