Preparation and Tribological Properties of Plasma Sprayed Ni/h-BN Composite Coating

Ni/h-BN coating has the advantages of both oxidation resistance, corrosion resistance, a metal phase that guarantees a certain bonding strength between the coating itself and the substrate, and a non-metallic phase that plays a lubricating role, which is used in the field of aeroengines, it has broad prospects.Ni/h-BN coating was prepared on the stainless steel substrate by atmospheric plasma spraying technology.The influences of the spraying process on the coating structure, mechanical properties and tribological properties were investigated.The results show that the best spraying process is obtained as current of 500 A, voltage of 55 V, main gas of 60 L/min, and a powder feeding speed of 30 r/min.The corresponding spraying power is 27 kW.On this basis, the friction and wear properties of Ni/h-BN coating prepared when the process parameters are optimized under different load and sliding speed test conditions are furtherly studied.The friction coefficient is 0.60-0.70.The wear rate is 10^-4 mm³/ (N·m)and increases with the increase of the load.Taken 3 N load as the boundary point, the wear rate decreases rapidly after 3 N.The main wear mechanisms are abrasive wear and fatigue wear.