Interaction of a Crack in the Plasma-Sprayed Ceramic Coating with the Metal Substrate

摘要

Plasma-sprayed ceramic coatings contain a high density of intrasplat microcracks which are responsible for small Young's moduli and low fracture toughness. The extension of an initial surface crack in the direction to the interface, where the crack is repelled by the metal substrate with higher Young's modulus, is studied using the methods of fracture mechanics. It is shown that high tensile stresses induced by the crack in the interface can lead to a local decohesion along the interface so that the crack can deviate into the interface.