Submicrometric structure of superhard oxide coatings on the surface of refractory metals treated with high-frequency currents

摘要

As a result of heat treatment of titanium in the high-temperature range (1000-1200℃), a layer of rutile (TiO_2) is formed on the surface, the hardness of which can reach 60 GPa. The production of the coating includes an intensive growth of the crystals, spontaneous scale delamination (up to 100 μm thick) and formation of a submicrometric porous-crystalline structure of a superhard thin coating (about 0.5-1.5 μm thick). Preliminary tests have shown that the resulting coatings of the system "steel substrate - Ti+TiO_2" can be used as tool coatings in the treatment of structural steel (0.4-0.5 wt.% carbon content), as well as chromium steel 40Crl3 (0.4 wt.% carbon content, chromium - about 13 wt.%) with a hardness within 45 HRC. These coatings are also characterized by biocompatibility, which was previously proved by in vitro and in vivo tests.