Abstract: The thermoelasticity problem for a functionally graded coating bonded to metal substrate due to transient heating on the coating surface isconsidered. The functionally graded coating is a particulate composite with volume fractions continuously varying through the thickness. The coating was treated with a series of homogeneous layers with stepwise changing volume fractions. The dynamic thermal stresses are analyzed for various coating gradients. It is shown that heating rates have significant influences on the failure mechanism of coating. For larger heating rates, the surface cracking of the coating is caused by compressing stress. While for lower heating rates, the surface cracking of the coating is caused by tensile stress. While failure mechanics of surface cracking in mind, the optimization of coating composition is presented for different heating rates.

Key words: functionally graded material, thermal str ess, optimization, coating