LAUSR

Abstract On the surface of the “Ti-base + Ta-coating” layered system, tantalum oxide coatings were obtained by induction heat treatment (IHT) within 600–1600 °C for 1–120 s. It was established that in the entire range of temperature and duration of IHT, the highest oxide with an oxygen concentration C[O] = 70.35–72.48 at.% was formed on tantalum. An oxide coating without cracks having an average grain size DG = 170–340 nm and pore size DP = 130–150 nm was formed at T = 1000–1050 °C. With an exposure time t = 30–120 s in the temperature range from 850 to 900 to 1000–1050 °C, high hardness values about 39–47 HRA (105–135 HV) for the tantalum layer and about 69–84 HRN15 (240–495 HV) for the near-surface layer were noted. These samples also had a superhard oxide coating with H0.01 = 55.27 ± 16.00 GPa and H0.1 = 39.09 ± 13.10 GPa. The results of the study of these samples showed that high microhardness of 1579 ± 537 HV0.2 combined with high Rockwell hardness and low defectiveness of the oxide coating allowed the creation of a mechanically stable “Ti-base + (Ta, Ta2O5)-coating” layered system.