Tribological behavior of diamond particles reinforced hafnium matrix composite coatings on Ti6Al4V

The diamond particles reinforced hafnium matrix composite coatings are prepared by the double glow plasma surface alloying technique combined with the microwave plasma chemical vapor deposition process (MPCVD). The effect of the Hf diffusion layers and diamond particles on their phase transformation, microstructure evolution, and wear behavior is systematically investigated. The results reveal that the surface of the Hf-alloying coating which is fabricated by plasma surface metallurgy emerged discrete micropores due to the Kirkendall effect during the plasma reverse sputtering. With the reverse sputtering time increasing, the general pore size increases, and the deposition layer has been completely sputtered out, leaving the Hf diffusion layer with a thickness of about 10 μm. After diamond particles deposition by MPCVD, the diamond particle reinforced hafnium matrix composite coatings with carbide and diamond coexisting were formed. The wear experiments were conducted in ambient air with a reciprocating friction tester, demonstrating that the diamond particle reinforced hafnium matrix composite coatings exhibited good antifriction performance with the decrease of wear rate by ∼8 times due to the lubrication effect of the diamond and graphite particles. •Diamond particles reinforced hafnium matrix composite coatings was fabricated.•The Hf diffusion layer was composed of Ti, Hf, Ti–Hf solid solution.•The composite coatings exhibited good antifriction performance.•Wear rate decrease ∼8 times through the lubrication effect of the diamond particles.