Kinetics of destructive hydrogenation of Ti2Cu and γ-TiCu intermetallides

Abstract

The kinetics of Ti 2 Cu and γ-TiCu destructive hydrogenation is examined. The research focuses on Ti 2 Cu and γ-TiCu samples in the form of plates, powders, and compacted powders and ingots. It is determined that the hydrogen pressure, temperature, and surface area of the intermetallides proportionally influence the rate of destructive hydrogenation of Ti 2 Cu and γ-TiCu in general and of each component in particular: hydrogen dissociation, hydrogen diffusion, and reaction rates. It is shown that pressure has a greater effect on the maximum hydrogenation rate than temperature. Higher titanium content of the intermetallides, other conditions being equal, increases the rate of the reaction and thus of the destructive hydrogenation. The compaction of Ti 2 Cu and TiCu powders and ingots intensifies the destructive hydrogenation process. This is due to the formation of catalytic juvenile intermetallic surfaces and to additional self-acceleration of surface reactions through autocatalysis. Of all the examined samples, the compacted ingots have the best kinetic characteristics because of the smallest specific fraction of oxidized surface. This conclusion is very important for application of the destructive hydrogenation process.We previously [1] examined the structural and phase mechanism of the destructive hydrogenation (DH) of intermetallide Ti 2 Cu. It is shown that the intermetallide interacts with hydrogen according to the destructive hydrogenation reaction resulting in titanium dihydride and copper. The rate of interaction with hydrogen is a characteristic that determines how efficient hydrogen treatment of functional materials is. The literature data on the hydrogenation of Ti 2 Cu and TiCu [2-6] focus on the analysis of the phase composition of reaction products rather than on the kinetics of the process.The objective of this paper is to examine the rate of the first destructive hydrogenation of intermetallides Ti 2 Cu and γ-TiCu and to find ways to accelerate the process.The starting intermetallides, Ti 2 Cu and γ-TiCu, were produced from iodide titanium and copper melted in the weight ratios 60 : 40 and 43 : 57 in a MIFI-9-3 arc furnace in high-purity argon. The alloys were annealed in vacuum at 973 K for 4 h. X-ray diffraction revealed that the starting intermetallides Ti 2 Cu and γ-TiCu consisted of single phases.