Thermal stability of amorphous alloys Mg65Cu25Y10, Mg63Ni30Y7 after electrochemical hydrogen absorption

Thin ribbons of the metallic glass Mg65Cu25Y10 and Mg63Ni30Y7 obtained by melt spinning were saturated with atomic hydrogen during electrochemical decomposition of water. The amount of absorbed hydrogen was as high as 4 mass% for the alloy Mg65Cu25Y10Hx and 1.5 mass% for the alloy Mg63Ni30Y7Hx. As the hydrogen content increases up to 3.6 mass%, the amorphous structure of the copper-containing alloy is transformed to a nanocrystalline structure with formation of magnesium and yttrium hydrides and also the intermetallic Cu2Mg at room temperature. The appearance of crystalline compounds during saturation with hydrogen leads to a decrease in the thermal stability of the amorphous alloy and a shift of the differential scanning calorimetry curves toward lower temperatures. In the presence of nickel, the thermal stability of the amorphous alloy Mg63Ni30Y7Hx increases with hydrogen saturation. After heating up to the crystallization temperature, the compounds Mg2NiH0.3 and YH2 appear.