Diamond particles-reinforced Ni-based composite coating on Ti6Al4V alloy: Microstructure, mechanical, dynamic impact and dry-sliding tribological properties

Diamond particles-reinforced Ni-based composite coating was fabricated on Ti6Al4V by vacuum cladding. The microstructure, phase composition, hardness, dynamic impact and dry-sliding tribological properties of the coating have been investigated systematically. The results demonstrate that the coating consists of a tough TixNiy/Ti3Al matrix filled with hard phases of TiC, Ti3SiC2 and TiC/CrxCy covered diamond. Benefiting from the high-temperature diffusion, the coating is well-metallurgically bonded with the substrate. Compared with the Ti6Al4V substrate, the overall macro hardness (H) and nanoindentation hardness (HIT) of Ni-based composite coating increase by 1.2 times and 3.5 times, respectively. The coating has a complete residual indentation under the high frequency of impact. Its diameter and depth are 90 % and 86 % of the substrate, respectively, indicating that the coating has relatively excellent impact toughness. Further, the coating has good wear resistance under high load. Its wear rate is 7.79 x 10-5 mm3/Nm, which is only 1/6 of the Ti6Al4V substrate. Therefore, the coating has good comprehensive performance and potential practical applications.