Abstract: Articles are disclosed which bear a carbon coating layer, wherein carbon-carbon bonding within the coating layer is mostly of the sp2 form: wherein the coating has a specific wear rate under wet conditions of less than 10−6 m3/Nm: wherein the coating has an adhesion critical load of at least 70N: wherein the coating has a hardness of at least 1000 VHN: wherein the coating has a coefficient of friction (dry) of not more than 01. The coating may be a multi-layer coating containing successive metal-containing and carbon layers. The article may be constituted as a medical prosthesis. Methods are disclosed of forming hard wear resistant carbon coatings by sputter ion plating with at least one carbon target in which an ion current density of for example above 0.

Abstract: Articles are disclosed which bear a carbon coating layer, wherein carbon-carbon bonding within the coating layer is mostly of the sp2 form: wherein the coating has a specific wear rate under wet conditions of less than 10−6 m3/Nm: wherein the coating has an adhesion critical load of at least 70N: wherein the coating has a hardness of at least 1000 VHN: wherein the coating has a coefficient of friction (dry) of not more than 01. The coating may be a multi-layer coating containing successive metal-containing and carbon layers. The article may be constituted as a medical prosthesis. Methods are disclosed of forming hard wear resistant carbon coatings by sputter ion plating with at least one carbon target in which an ion current density of for example above 0.

Abstract: An unbalanced magnetron sputter ion plating system has a first magnetron with a first target of metal sulphide (e.g. MoS2) and a second magnetron with a second target of metal (e.g. Titanium). In order to recover water and sulphur impurities from the surfaces of the coating chamber the metal target is energised in a pre-coating ion cleaning operation. The Titanium target remains energised during the deposition of the molybdenum-sulphur coating to produce a MoxTiySz coating where x+y≈1 and Z≈2. Best results are achieved if the Titanium content is about 18% or less by weight of the total coating content.