Superhard Ta–O–N coatings produced on titanium using induction physical vapor deposition

Abstract

Due to simulation by the finite element method, the temperature fields in the “inductor – tantalum target – titanium product” system were calculated depending on the inductor current and exposure time during induction physical vapor deposition (IPVD). The conditions under which the tantalum target was heated to the evaporation temperature in vacuum were determined. It was experimentally established that after IPVD at an operating current IO = 500–800 A (inductor current IIND from 4.9 to 6.7 kA), electrical power consumption PC = 1.67–3.32 kW, and exposure time t = 30–300 s, there was an in increase in the content of tantalum C[Ta]= 21.6–42.1 at.%, oxygen C[O]= 16.5–43.5 at.%, and nitrogen C[N]= 2.6–9.4 at.% on the surfaces of titanium samples. According to the XRD data, the resulting thin-layered structure on the titanium samples was mainly presented by the following crystalline phases: tantalum oxides (Ta2O5, Ta2O), tantalum oxynitride/nitride (TaON, TaN), titanium oxides (TiO2, TiO), and metal phases (α-Ta, α-Ti). It was found that during IPVD hard H = 18.85–39.17 GPa and superhard H = 46.18–89.88 GPa tantalum-containing coatings were obtained on the surfaces of titanium samples. The highest resistance to plastic deformation (by 50–70%) and wear resistance of titanium samples with tantalum-containing coatings was observed in the case of short exposure t < 60 s during IPVD.