Quick ultra-low friction in ceramics induced by high-strength nano surface film

Serious wear during running-in period significantly limited the application of ceramics in industry. With poor activity, ceramic contact surface is hard to be protected during friction. In this study, ceramics tribological properties are significantly enhanced and ultra-low friction is achieved in short time by formation of high-strength nano surface film. Copper nanoparticles with linear and cubic morphologies were synthesized and dispersed into water-based lubricants for silicon nitride ceramic friction pairs. A 1:1 mixture of copper nanoparticles with linear and cubic morphologies exhibits the best lubrication performance at an optimal concentration of 0.2 wt%. The result shows an 87.01 % reduction in the coefficient of friction, and a wear rate of 0.18 % of that obtained in the case of deionized water. High-strength protective film is found generated on the ceramic surface, which reduces wear and promotes the forming process of ultra-smooth surface to achieve ultra-low friction. Based on the characterization results, lubrication mechanism is elucidated, quick generation of surface film with high strength is the essential for reducing wear and running-in period.