Fracture toughness of plasma spraged YSZ coatings

The authors considered the fracture toughness of plasma sprayed YSZ coating from the view of the effect of spray distance by using TDCB method. It was recognized that the cracking propagated through the interface of plattened particles in YSZ coating. The fracture toughness of YSZ coating was uniform on short spray distance. But the longer a spray distance became, the smaller a fracture toughness became on the spray distance over some value. This phenomenon of YSZ coating is similar to that of Al ₂O ₃ coating. The dependence of fracture toughness of YSZ coating on spray distance was same as that of bonging rate at the interface of plattened particles on spray distance. It was recognized that the fracture toughness of YSZ coating was controlled by bonding rate.