Mechanical properties of R.F. magnetron sputtered W-C films on stainless steel

Abstract

Mechanical properties of r.f. reactive magnetron-sputtered tungsten carbide films prepared in the substrate temperature range 300-500 °C under two different configurations of sputtering were studied. Depending on the geometrical configuration, a single-phase f.c.c. and mixture of phases (WC hexagonal, W₃C A-15, and carbon in diamond and graphite) were observed. Microhardness values of about 3200 kgf mm^-2 in single-phase films and about 2365 kgf mm^-2 in mixed-phase films were found. The adhesion value measured by crack indentation was 3.5 × 10⁷ g cm^-2 for various films on stainless steel substrates. A coefficient of friction as low as 0.09 and high wear resistance between W-C coated stainless steel disc and stainless steel pins were found under lubricating conditions. The microhardness, friction and wear characteristics of these films are discussed.