Corrosion and wear properties of TB2 titanium alloy borided by pack boriding with La2O3

Abstract

To improve the surface performance of TB2 alloy, pack boriding was performed at 1100 °C for 20 h with 4 wt.% La2O3. The composition and thickness of boride layer and corrosion and wear properties of borided TB2 alloy were measured. The results show that La2O3 can promote the growth, continuity, and compactness of boride layer, and the length of TiB whisker increases from 16.80 to 21.84 μm. The reason is that La2O3 can react with B to form La−B active groups and further to improve the growth of the boride layer. The wear and corrosion resistances of TB2 alloy are enhanced by boriding with La2O3. The wear mechanisms are adhesive wear and abrasive wear for unborided and borided TB2 alloys, respectively, and the corrosion mechanism is changed from local corrosion (unborided TB2 alloy) to uniform corrosion (borided TB2 alloy).