High-capacity hydrogen storage alloy and method for producing the same

Abstract

A high-capacity hydrogen storage alloy has a crystal structure containing a body-centered cubic structure as a single or main phase and made of a composition represented by the general formula Ti a Cr b Mo c Fe d , in which a is in a range of from 25 to 45% by atomic weight, b is in a range of from 30 to 65% by atomic weight, c is in a range of from 5 to 40% by atomic weight, and d is in a range of from 0 to 15% by atomic weight. In production of the alloy, a heat treatment is performed at a temperature in a range of from 1,200 to 1,500° C. for 1 minute to 24 hours and then cooling is performed at a speed equal to or higher than the cooling speed obtained by water cooling.

What is claimed is:  
     
         1 . A high-capacity hydrogen storage alloy comprising a crystal structure containing a body-centered cubic structure as a single or main phase and made of a composition represented by a general formula Ti a Cr b Mo c : 
 wherein a is in a range of from 25 to 45% by atomic weight, b is in a range of from 30 to 65% by atomic weight, and c is in a range of from 5 to 40% by atomic weight.    
     
     
         2 . A high-capacity hydrogen storage alloy comprising a crystal structure containing a body-centered cubic structure as a single or main phase and made of a composition represented by a general formula Ti a Cr b Mo c Fe d : 
 wherein a is in a range of from 25 to 45% by atomic weight, b is in a range of from 30 to 65% by atomic weight, c is in a range of from 5 to 40% by atomic weight, and d is not larger than 15% by atomic weight.    
     
     
         3 . A high-capacity hydrogen storage alloy according to  claim 1 , wherein a treatment that said hydrogen storage alloy is heated at a temperature in a range of from 1,200 to 1,500° C. for 1 minute to 24 hours and cooled at a cooling speed not less than the speed of water cooling, has been performed.  
     
     
         4 . A method for producing a high-capacity hydrogen storage alloy, comprising the steps of: 
 applying a heat treatment to a material made of a composition defined in  claim 1  to thereby heat said material at a temperature in a range of from 1,200 to 1,500° C. for 1 minute to 24 hours; and    cooling said material at a cooling speed not less than the speed of water cooling after said heat treatment.