Mechanical properties of reactively sputtered (Ta,Si)N hard coating

초록

The mechanical properties and the chemical bonding characteristics of a ternary hard coating based on (Ta,Si)N deposited onto a high-speed tool steel by reactive sputtering were studied. From an Auger electron spectroscopy, it was found that the nitrogen content in the coating increased with the nitrogen gas flux during deposition. In as-deposited condition, the major phase of the coating was TaN containing Si in solution. The micro-hardness of the coating increased with the flux of the nitrogen gas during sputtering, reaching to 17GPa. Post-coating annealing heat treatment, paricularly the one at 1000C, resulted in a change in the chemical composition of the coating, mainly because of a reverse diffusion of Fe and C from the substrate, which yielded a TaC phase. The hardness as well as the adhesion strength of the coating were increased by the annealing treatment at 1000C, The XPS analysis of the coating layer found that Fe and Si in the coating did not form chemical compound but enriched the interface of the coating and the substrate