Structural and phase transformations and rate of Ti2Co and TiCo interaction with hydrogen and synthesis of nondestructive nanostructured titanium hydride composites

Abstract

The paper examines the sequence of structural and phase transformations and the rate of Ti2Co and TiCo interaction with hydrogen. Destructive hydrogenation of Ti2Co is used to produce nondestructive nanostructured titanium hydride composites. Thermodynamic analysis has shown that Ti2Co and TiCo destructive hydrogenation is thermodynamically favored in the temperature range 298–973 K. In the temperature range 773–973 K, Ti2Co interacts with hydrogen by destructive hydrogenation reaction, in which hydrogen is dissolved in the intermetallic compound, titanium is selectively hydrogenated to cubic TiH1.9, and titanium-depleted TiCo and TiCo2 intermetallics are successively formed in accordance with the Ti–Co phase diagram. The rate of Ti2Co destructive hydrogenation is proportional to temperature, hydrogen pressure, and surface area of the starting samples. Compound TiCo is hydrogenated to form a solution of hydrogen in Ti1+yCo, intermetallic TiCo2, and a solution of hydrogen in β-titanium. Nondestructive composites with nanostructured components are synthesized by Ti2Co destructive hydrogenation.