Deformation and delamination behavior of sputter-deposited film on the conical protrusions formed by sputter-etching of stainless steel wire

The surface of type 304 stainless steel wire was sputter-etched to form conical protrusions, and a Ag–1 mass%Ti film was sputter-deposited on the protrusions. Bending tests of the wire showed that delamination occurred along the interface between film and substrate for the wire without protrusions at a small strain whereas only fine cracking and partial delamination (limited to the skin of film) occurred for the wire with protrusions at a much higher strain. It is suggested that the reason for the increase in delamination strength is the increase in the interfacial area and anchor effect introduced by the protrusions.