The microstructure and wear properties of diamond composite coatings on TC4 made by induction brazing

In this work, diamond and diamond/graphite composite coatings were obtained on the surfaces of TC4 (Ti-6Al-4V) alloy by high-frequency induction heating the preplaced powders in argon. The microstructures of the composite coatings were studied by scanning electron microscope, energy dispersive spectrometer and X-ray diffractometer, and the wear resistance of coatings was assessed by rubber wheel abrasion test. The results showed that the composite coatings had good metallurgical bonding with the substrates. TiC and ZrC particles in-situ generated in diamond/graphite composite coating improved the wear resistance of alloy matrix, but the free graphite weakened the wear-resistant structure of the coating. In the wear tests, abrasive wear was the main wear mechanism for diamond composite coating and diamond/graphite composite coating. Beside the elements of brazing alloy, carbon, aluminum and oxygen were the main elements detected at the surfaces of the two coatings.