Studies on Elastic–Plastic Behavior of Plasma-Sprayed Ceramic Coatings on TI–6AL–4V Substrate

The elastic–plastic contact between a rigid ball and flat plate with three different types of ceramic coatings was analyzed using the ball indentation test and finite element method (FEM). Micrometer-sized powders of the following compositions were plasma sprayed onto the Ti–6Al–4V substrate: (i). Al2O3 (AO), (ii). 8 mol% yttrium stabilized zirconia (8YSZ), and (iii). Al2O3–40 wt% 8YSZ (A4Z). The loading and unloading results revealed that the FE model was capable of reproducing the experimental loading and unloading curves for the coated samples. The result from the study suggested that the coating with materials Al2O3–40 wt% 8YSZ was the most desirable one for protecting the substrate against yielding since plastic deformation does not initiate until a large plastic zone has been developed in the substrate.