Thermochemical Analysis of Hydrogenation of Pd-Containing Composite Based on TiZrVNbTa High-Entropy Alloy

The microcalorimetric hydrogen titration technique combined with conventional volumetric measurements has been used to reveal peculiarities of the hydrogenation of the single-phase TiZrVNbTa equiatomic high-entropy alloy. The alloy has been produced in the form of microfibers by the pendent drop melt extraction technique. Palladium coating of the fibers has been applied to enable first hydrogenation at room temperature without additional activation. An analysis of the obtained data allows us to evaluate the dependence of hydrogenation enthalpy on the hydrogen concentration in the alloy. Three concentration ranges, presumably related to the formation of the hydrogen solid solution, monohydride and dihydride phases, have been identified, and the corresponding ?H values of about -100, -80 and -60 kJ/mol H-2, respectively, have been determined.

Automated summary

The peculiarities of hydrogenation in the single-phase TiZrVNbTa equiatomic high-entropy alloy were revealed using a combination of microcalorimetric hydrogen titration technique and conventional volumetric measurements. The alloy was produced as microfibers using the pendent drop melt extraction technique and Palladium coating was applied to enable first hydrogenation at room temperature without additional activation. The analysis of the obtained data allowed for evaluation of the dependence of hydrogenation enthalpy on the hydrogen concentration in the alloy, identifying three concentration ranges corresponding to the formation of hydrogen solid solution, monohydride, and dihydride phases with determined ?H values of about -100, -80, and -60 kJ/mol H-2, respectively.