Tribological performance of hydrogenated diamond-like carbon coating deposited on superelastic 60NiTi alloy for aviation self-lubricating spherical plain bearings

It is imperative to develop a novel matching of metallic substrate and self-lubricating coating for aircraft spherical plain bearing in a wide range of service conditions. As a new type of superelastic material, 60NiTi alloy meets the performance requirements of aerospace bearing materials, but exhibits poor tribological performance, especially under the conditions of dry sliding friction. A Hydrogenated Diamond-Like Carbon (H-DLC) coating was deposited on the 60NiTi alloy to improve its tribological performance. The microstructure and mechanical behavior of the 60NiTi alloy and its H-DLC coating were explored. Results show that improvement of friction and wear performance of the H-DLC coating deposited on the 60NiTi substrate is mainly achieved by graphitization at the friction interface and the transfer film produced on the counterpart ball. The increased friction load leads to intensification of graphitization at the friction interface and formation of continuous and compact transfer film on the surface of the counterpart ball.