Adhesion evaluation of plasma sprayed coatings using piecewise linear regression analysis

The critical load for adhesion of 75% WC-Co+25%Ni alloy plasma sprayed coatings was evaluated by an interfacial indentation test. A statistical analysis—piecewise linear regression—was used to estimate the critical load P _C and its confidence interval. It was determined that a post heat treatment increases the practical adhesion load of plasma sprayed coatings. This increase was attributed to interdiffusion mechanisms verified at the interface between the coating and substrate.