RARE-EARTH METAL NICKEL HYDROGEN OCCLUSIVE ALLOY INGOT AND METHOD FOR PRODUCTION THEREOF

摘要

A rare earth metal-nickel hydrogen occlusive alloy ingot contains 90 vol% or more of crystals having a crystal grain size of 1 to 50 mu m as measured along a short axis of the crystal and 1 to 100 mu m as measured along a long axis of the crystal. A method for producing the rare earth metal-nickel hydrogen occlusive alloy ingot involves melting a rare earth metal-nickel alloy and uniformly solidifying the alloy melt to have a thickness of 0.1 to 20 mm under cooling conditions of a cooling rate of 10 to 1000 DEG C/sec and a sub-cooling degree of 10 to 500 DEG C.