Research on the deoxidation process of titanium alloy powders with calcium hydride

Titanium and its alloy powders are highly sensitive to oxygen, and the limited development of deoxygenation processes restricts the recycling of powders with elevated oxygen levels. In this study, we employed calcium hydride as a deoxygenating reductant and implemented a normal pressure solid-state deoxygenation technique, the in-situ reactions of Ca and H 2 generated from the decomposition of calcium hydride, along with partial gaseous CaH, effectively reduce the oxygen content in the powders. By performing the deoxygenation above the β-transition temperature, we successfully reduced the oxygen content in titanium alloy powder from 3593 ppm to 839 ppm. The deoxygenated powder retained the original appearance, size, and morphology of the initial powder, with no residual impurity elements. The thickness of the surface oxide film was reduced to 3.5 nm, and the interstitial oxygen content was lowered to 300 ppm. In comparison with the current deoxidation in solid-state process, this method significantly reduced the total process time while achieving an equivalent oxygen reduction rate.