The thermodynamic possibility and conditions of Ti 2 Cu hydrogenation and recombination are assessed. The mechanism of Ti 2 Cu interaction with hydrogen between 293 and 973 K at pressure 1.0 MPa is studied. The interaction of Ti 2 Cu with hydrogen is thermodynamically possible in the destructive hydrogenation region over a wide temperature range. X-ray diffraction shows that destructive hydrogenation products are titanium dihydride and copper-rich intermetallic phases and copper depending on reaction conditions. According to the established mechanism of Ti 2 Cu destructive hydrogenation, hydrogen selectively interacts with titanium leaving Ti 2 Cu composition as follows: β-TiH y (bct-bcc) → TiH 1.92 (fcc). The initial Ti 2 Cu composition is recombined from destructive hydrogenation products (titanium dihydride and copper) in vacuum and hydrogen. The minimum temperature of Ti 2 Cu vacuum recombination is 1050 K and ensures complete TiH 2 decomposition. The recombination of Ti 2 Cu in hydrogen can occur at temperatures above 907 K.Compounds of titanium with copper are promising functional materials with high hardness, electrical and thermal conductivity, and satisfactory sound absorptivity. Coatings based on Ti-Cu intermetallides can greatly improve the sliding surfaces and tribotechnical properties in general. There are six intermetallic compounds known in the Ti-Cu system: Ti 2 Cu, TiCu, Ti 3 Cu 4 , Ti 2 Cu 3 , TiCu 2 , and β-TiCu 4 [1]. This paper considers the interaction of hydrogen with Ti 2 Cu, which has tetragonal crystal lattice of MoSi 2 type (structural group 17 4h D ) with parameters a = 0.2943 nm and c = 1.0784 nm [2].The interaction between Ti 2 Cu and hydrogen was earlier studied in [3][4][5][6][7], but none of the papers provided diffraction patterns of the reaction products. Nevertheless, it is stated in [3,4] that the reaction products are represented by titanium hydride and copper above 473 K and by direct hydride Ti 2 CuH 2.6 below 473 K [5, 6]. Padurets and colleagues [7] obtained TiCuH 2 and TiH 2 by Ti 2 Cu hydrogenation at 293-673 K and hydrogen pressure 0.1 MPa. The isothermal line of Ti 2 Cu-H equilibrium at 773 and 823 K was also studied [4]. Five pressure plateaus associated with heterophase composition of the system that interacts with hydrogen are revealed. Hence,

No 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.