Enhancing disproportionation resistance of Zr2Co-based alloys by regulating the binding energy of H atom

Considering the scarcity and radioactivity of tritium, developing efficient tritium recovery and storage technology is essential for the safety and stability of nuclear fusion reactions. Zr2Co alloy is a prospective tritium-getter material, while its poor disproportionation resistance limits the practical application. To address this issue, Zr2Co alloy was modified by alloying and Zr2Co0.9M0.1 (M = Cr, Mn, Fe, Ni, Cu) alloys were prepared. Performance test results indicate that all Zr2Co0.9M0.1 alloys exhibit the main phase corresponding to Zr2Co phase and their hydrogenation phases belong to Zr2CoH5 phase. Alloying improves the hydrogen storage capacity and reduces the hydrogenation equilibrium pressure of Zr2Co alloy. Zr2Co0.9Cr0.1, Zr2Co0.9Mn0.1, and Zr2Co0.9Fe0.1 alloys have hydrogen storage capacities above 2 wt% and hydrogenation equilibrium pressures approximately 10−7 Pa at room temperature. Furthermore, Zr2Co0.9M0.1 alloys have better disproportionation resistance compared to Zr2Co alloy. Notably, Zr2Co0.9Fe0.1 and Zr2Co0.9Ni0.1 alloys possess interstitial sites with moderate hydrogen binding energies, resulting in stronger disproportionation resistance than that of other alloys. Therefore, Zr2Co0.9Fe0.1 alloy is the most promising tritium-getter material among the studied materials. The cycling performance of Zr2Co0.9Fe0.1 alloy is investigated and a superior capacity retention of 94 % is found out. This work shed light on the further exploration of tritium-getter materials. [Display omitted]