HYDROGEN STORAGE ALLOY, AND METHOD OF HEAT TREATMENT FOR HYDROGEN STORAGE ALLOY

摘要

PPROBLEM TO BE SOLVED: To provide a hydrogen storage alloy which has improved alloy characteristics such as activation, increase in the reaction rate of hydrogen storage/discharge, and increase of the amount of hydrogen storage in a TiCrV based hydrogen storage alloy having a BCC structure as the main phase, and to provide a method of heat treatment for the hydrogen storage alloy. PSOLUTION: A hydrogen storage alloy expressed by the formula of TiSBa/SBCrSBb/SBVSBc/SBMSBd/SB, including a C15Laves phase being a low temperature equilibrium phase and having a BCC structure as the main phase is subjected to heat treatment so as to be melted, thereafter subjected to homogenizing heat treatment at 1,200C to a melting point for 1 to 24 hr in an inert gas atmosphere, in a reducing gas atmosphere or in a vacuum, and cooled down at a cooling rate of 10 to 200C/hr in an inert gas atmosphere, in a reducing atmosphere or in a vacuum into a mixed phase region of a BCC structure phase and a C15Laves phase; wherein: (a) is 20 to 45 atomic%; b is 30 to 70 atomic%; c is 5 to 45 atomic%; d is 0 to 15 atomic%; and M is one or more kinds of metals selected from Fe, Al, Cu, Ni and Mo. By the invention, the alloy characteristics of the TiCrV based hydrogen storage alloy can be improved without causing the requirement for equipment investment for rapid cooling treatment or the like and the increase of alloy production cost. PCOPYRIGHT: (C)2004,JPO