CRACK GROWTH IN THERMALLY SPRAYED CERAMIC COATINGS

摘要

Thermally sprayed ceramic coatings contain a high density of microcracks which are responsible for small Young's moduli, nonlinear behaviour at higher com-pressive or tensile stresses, and for 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 and finite elements. 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 continue and deviate into the interface.