PRODUCTION AND PROPERTIES OF OXIDATION-RESISTANT SPARK COATINGS ON TITANIUM ALLOYS

摘要

The paper examines the deposition of spark coatings from Ni–Cr–Al alloy, pressed and sintered in vacuum, on titanium alloys. The spark deposition parameters are optimized to produce coatings with a thickness to 30 μm, density not lower than 80%, and hardness about 8 GPa. It is shown that sparkdeposited coatings on VT6 and VT22 alloys permit increase in their oxidation resistance by a factor of 1.5 to 2.5 during isothermal holding at 800℃. This increase is due to the formation of oxidationresistant titanium phases on coatings, which prevent the diffusion of elements from air into the coating.