Reaction mechanisms for Ti coatings on diamond

Abstract

Efficient interface management between diamond and metal is crucial for achieving optimal performance in metal-matrix/diamond composites. Here, the Ti coatings prepared at various pressures were deposited on diamond particles by DC magnetron sputtering. The microstructure and bonding strength of the resulting coatings were systematically investigated. The results showed that the microstructure of the Ti coatings depended on the deposition pressure. All coating surfaces had a granular morphology, and the augment of deposition pressure was favorable for refining the coatings' grains. The Ti coating prepared at 1.0 Pa was fine and uniform with no obvious defects, displaying the optimal deposition quality and bonding strength. Furthermore, it was found that the annealing temperature played a key role in the reaction between the Ti coating and the diamond. The TiC phase in the Ti-coated diamond particles exhibited a progressive increase with rising temperature, and the Ti-coated diamond underwent completely transformation into TiC-coated diamond at 1000 °C. The experimental results and molecular dynamics simulation revealed that the Ti coating reacted more violently with the diamond-(100) facet than it did with the diamond-(111) facet at high temperature. This work provided a new solution for interface management strategy of high-quality metal-matrix/diamond composites.