Reactive and non-reactive high rate sputter deposition of Tungsten carbide

Tungsten carbide coatings were deposited onto molybdenum and cemented carbide substrates using d.c. and r.f. magnetron sputtering. Tungsten targets were used in reactive (argon plus acetylene) atmospheres and tungsten carbide targets were used in non-reactive (argon) atmospheres. Substrates were r.f. biased with d.c. potentials of up to -1000 V. Sputtering from WC targets produced carbon-deficient mixed-phase structures with β-WC_1-x as the main component. Reactive deposition led to highly disordered W-C films which X-ray studies showed to be almost amorphous. Fractograms revealed very fine-grained to fractured amorphous film structures in all deposition modes. Hardness values higher than 3000 HV 0.05 were reached using non-reactive d.c. sputtering.