Abstract
In order to evaluate the delamination strength of hard films bonded on ductile substrates, a convex edge indent method was proposed. A transparent glass plate was bonded on an transparent acrylic resin substrate, and one end of the specimen was machined to a rectangular shape. A conical indenter was gradually pressed to a glass plate at a distance from the edge observing the formation and propagation of the interfacial crack. The result showed that the interfacial crack initiated around the indent point at an indentation load about 1/3 of the delamination load, and propagated with increasing the indentation load. Delamination of the glass plate occurred after the crack front approached the edge. The interfacial fracture toughness was derived fracture mechanically, and applied to the. The interfacial fracture toughness ranged between 2-7kJ/m^2, decreased with increasing the width of the edge.
