Hydrogen absorption in uranium-based alloys with cubic γ -U structure*

L Havela and N-T H Kim-Ngan

Abstract

UH₃-type hydrides were formed by hydrogenation of splat-cooled U-based alloys upon applying high H₂ pressures (>2.5 bar). Hydrogenation of U_1−x Mo _x alloys (with x  ≥  0.12 (12 at.% Mo) containing the cubic γ-U phase leads to a formation of nanocrystalline β-UH₃, why those of U_1−x Zr _x alloys (with x  ≥15 at.% Zr) implies a pure α-UH₃. The Curie temperature of hydride (UH₃)_0.85Mo_0.15 reaches 200 K; it may be the first U-based ferromagnet with such high T _C. The results reflect the dominant U–H interaction