EFFECTS OF NEUTRAL GAS INCORPORATION IN MOLYBDENUM COATINGS PRODUCED BY MAGNETRON SPUTTERING

Molybdenum coatings were produced by planar magnetron sputtering, using argon or neon as the discharge gas. With argon, the hardness of the molybdenum layers was found to increase with the bias voltage Us applied to the substrate, up to values of 16,000 MPa (HV 0.05) for Us=-600 V. The hardness of the layers produced using neon is also high (15,000 MPa (HV 0.05)) but in this case it is independent of the bias voltage. Various analyses show that these hard layers contain argon or neon, are highly textured and show high residual stresses in compression. Channelling of the incident energetic particles is assumed to account for the occurrence of the (111) texture. Algthough the highest hardness values are found when the operating conditions permit incorporation of the discharge gas, hardening seems to depend on the mechanisms involved in the incorporation of the neutral gas than on the actual gas content.