Effects of residual stress on thickness and interlayer of thermal barrier ceramic MgO-ZrO2 coatings on Ni and AlSi substrates using finite element method

Thermal analysis evolution of MgO-ZrO2/NiCrAlY coatings on Ni metal and AlSi alloy (LM13) substrates was studied. MgO-ZrO2/NiCrAlY coatings were deposited on metallic substrates using an atmospheric plasma spray technique. The coatings were characterized by optical microscope and scanning electron microscope. Thermal loadings were applied to the model at the temperature range 800-1000 deg. C using finite element method. Methollographic examinations pointed out that coatings possessed porosity, oxide, unmelted and semi-melted particle, and inclusion. Finite element calculations showed that stress concentration was at higher levels in the coatings with AlSi substrates than that of Ni. It was also found that the larger residual stresses were obtained with an increase of the coating thickness and interlayer bond coatings decreased residual stresses