Anode plasma electrolytic borocarburising of alpha + beta-titanium alloy

Abstract

The structure of alpha + beta-titanium alloy, its microhardness, surface roughness, and wear and corrosion resistance after anode plasma electrolytic borocarburising (PEB/C) in electrolyte containing boric acid, glycerol and ammonium chloride were investigated. An X-ray diffractometer and scanning electron microscopy were used to characterize the phase composition and structure of the modified surface. Tribological properties of treated titanium alloy were evaluated using a ball-on-disc tribometer under dry testing conditions. The effect of electrolyte compositions on corrosion resistance of the PEB/C samples was examined by means of potentiodynamic polarization in Ringer's solution. It was shown that the electrolyte containing boric acid, glycerol and ammonium chloride provided the saturation of alloy with boron, carbon and oxygen and formation of TiO2 with rutile structure and boron/carbon solid solution in titanium. The anode PEB/C resulted in a decrease in surface roughness by 2.5 times, corrosion current density by 9 times, wear rate by 54 times and an increase in microhardness to 1075 HV10.