Mechanical properties and fretting behavior of sulfide film

Abstract

On sliding or fretting contacts, sulfide films may cause many kinds of problems. On some conditions, sulfide films may be removed; and on other conditions, they are very sticky. These phenomena are not fully understood and the characteristics of sulfide films are not very clear. Many papers have been published on electric contact behavior of sulfide films. However, mechanical properties of them are neglected. Nevertheless, the mechanical properties may be very helpful to understand their electric contact behavior. This is the basic requirement of this paper. Wires of copper and silver, copper coupons, and silver plated coupons were exposed in H/sub 2/S gas environment. Wires and coupons after corrosion were cross-sectioned to observe the growth of sulfide films which were identified by X-ray energy dispersive spectroscopy (XES). Tensile strength and Young's modulus of the wires covered by sulfide films were studied by the specific micro-tension testing machine. A tentative calculation was made for the tensile strength of Cu/sub 2/S. The mechanical property probe-Nano Indenter II was also used to measure Young's modulus of sulfide films covered on coupon surfaces. The relationship between electric contact behavior of sulfide films and mechanical properties are discussed.