Hydrogen storage metal alloy and production thereof

Abstract

A process for producing hydrogen storage metal alloys having a body-centered cubic structure-type main phase enabling the adsorption and desorption of hydrogen is provided which comprises the steps of: (1) melting a starting alloy brought to a predetermined element ratio to form a uniform heat (melting step), (2) keeping the homogenized alloy heat at a temperature within a range just below the melting point of the alloy for a predetermined time (heat treatment), and (3) rapidly cooling the alloy after the heat treatment (quenching step).

1 . A hydrogen storage metal alloy which has 
 having a main phase with a body-centered cubic structure enabling the adsorption and desorption of hydrogen, said alloy having    a composition of the following general composition formula:      Ti (100-a-0.4b) Cr (a-0.6b) M b      wherein M is vanadium (V), provided that 20≦a (at %)≦80, and 0≦b (at %)≦10.    
     
     
         2 . The hydrogen storage metal alloy according to  claim 1  wherein a level of the constituent element V contained in the alloy is within a range of 6±2 at %.  
     
     
         3 . A hydrogen storage metal alloy 
 having a main phase with a body-centered cubic structure enabling the adsorption and desorption of hydrogen, said alloy having    a composition of the following general composition formula:      Ti (100-a-0.4b) Cr (a-0.6b) M b      wherein M is at least a member selected from molybdenum (Mo) and tungsten (W), provided that 20≦a (at %)≦80 and 0≦b (at %)<5.    
     
     
         4 . The hydrogen storage metal alloy according to  claim 3  wherein a level each of the constituent element Mo and/or W contained in the alloy is within a range of 3±1.5 at %.  
     
     
         5 . A hydrogen storage metal alloy having 
 a main phase with a body-centered cubic structure the adsorption and desorption of hydrogen, said alloy having    a composition of the following general composition formula:      Ti (100-a-0.4b) Cr (a-0.6b) V (b-c) M c      wherein M is at least a member selected from molybdenum (Mo) and tungsten (W), provided that 20≦a (at %)≦80, 0≦b (at %)≦10, and 0≦c (at %)<5.    
     
     
         6 . The hydrogen storage metal alloy according to  claim 1  wherein the element X is admixed at its atom % concentration, d (at %), ranging within 0≦d (at %)≦20, the atomic radius of which is larger than that of Cr but smaller than that of Ti.  
     
     
         7 . The hydrogen storage metal alloy according to  claim 6  wherein the element X is at least one or more members selected from the group consisting of Al, Ge, Ga, Si, Au and Pt.  
     
     
         8 . The hydrogen storage metal alloy according to  claim 1  wherein the element T is admixed at its atom % concentration, e (at %), ranging within 0≦e (at %)≦10 and includes at least one or more members selected from the group consisting of Nb, Ta, Mn, Fe, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal), N, Ni, P, and Si.  
     
     
         9 - 12 . (canceled)  
     
     
         13 . The hydrogen storage metal alloy according to  claim 3  wherein the element X is admixed at its atom % concentration, d (at %), ranging within 0≦d (at %)≦20, the atomic radius of which is larger than that of Cr but smaller than that of Ti.  
     
     
         14 . The hydrogen storage metal alloy according to  claim 13  wherein the element X is at least one or more members selected from the group consisting of Al, Ge, Ga, Si, Au and Pt.  
     
     
         15 . The hydrogen storage metal alloy according to  claim 3  wherein the element T is admixed at its atom % concentration, e (at %), ranging within 0≦e (at %)≦10 and includes at least one or more members selected from the group consisting of Nb, Ta, Mn, Fe, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal), N, Ni, P, and Si.  
     
     
         16 . The hydrogen storage metal alloy according to  claim 5  wherein the element X is admixed at its atom % concentration, d (at %), ranging within 0≦d (at %)≦20, the atomic radius of which is larger than that of Cr but smaller than that of Ti.  
     
     
         17 . The hydrogen storage metal alloy according to  claim 16  wherein the element X is at least one or more members selected from the group consisting of Al, Ge, Ga, Si, Au and Pt.  
     
     
         18 . The hydrogen storage metal alloy according to  claim 5  wherein the element T is admixed at its atom % concentration, e (at %), ranging within 0≦e (at %)≦10 and includes at least one or more members selected from the group consisting of Nb, Ta, Mn, Fe, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal), N, Ni, P, and Si.  
     
     
         19 . The hydrogen storage metal alloy according to  claim 1  wherein the structure comprises a mono-phase structure.  
     
     
         20 . The hydrogen storage metal alloy according to  claim 3  wherein the structure comprises a mono-phase structure.  
     
     
         21 . The hydrogen storage metal alloy according to  claim 5  wherein the structure comprises a mono-phase structure.  
     
     
         22 . A hydrogen storage metal alloy having a main phase with body-centered cubic structure enabling the adsorption and desorption of hydrogen, said alloy having a composition of the following general composition formula:  
         Ti (100-a-0.4b-n1[d+e]) Cr (a-0.6b-n2[d+e]) V (b-n3[d+e]) X d T e    (I)  
       wherein 
 X is at least one or more other elements selected from the group consisting of Al, Ge, Ga, Si, Au and Pt,  
 T is at least one or more other elements selected from the group consisting of Nb, Ta, Mn, Fe, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal, N, Ni, P, and Si, and  
 20≦a (at %)≦80;  
 0≦b (at %)≦10;  
 0≦d (at %)≦20;  
 0≦e (at %)≦10 and  
 n1+n2+n3=1, or  
   Ti (100-a-0.4b-n1[d+e]) Cr (a-0.6b-n2[d+e]) M (b-n3[d+e]) X d T e    (II)  
 wherein  
 M is at least a member selected from molybdenum (Mo) and tungsten (W),  
 X is at least one or more other elements elected from the group consisting of Al, Ge, Ga, Si, Au and Pt,  
 T is at least one or more elements selected from the group consisting of Nb, Ta, Mn, Fo, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal, N, Ni, P, and Si, and  
 20≦a (at %)≦80;  
 0≦b (at %)≦5;  
 0≦d (at %)≦20;  
 0≦e (at %)≦10 and  
 n1+n2+n3=1, or  
   Ti (100-a-0.4b-n1[d+e]) Cr (a-0.6b-n2[d+e]) V (b-n3[d+e]) M (c-n4[d+e]) X d T e    (III)  
 wherein  
 M is at least a member selected from molybdenum (Mo) and tungsten (W),  
 X is at least one or more other elements selected from the group consisting of Al, Ge, Ga, Si, Au and Pt,  
 T is at least one or more other elements selected from the group consisting of Nb, Ta, Mn, Fe, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal, N, Ni, P, and Si, and  
 20≦a (at %)≦80;  
 0≦b (at %)≦10;  
 0≦c (at %)≦5  
 0≦d (at %)≦20  
 0≦e (at %)≦10 and  
 n1+n2+n3+n4=1.  
 
     
     
         23 . The hydrogen storage metal alloy according to  claim 22  wherein the elements of the alloy correspond to the composition of the following general composition formula:  
         Ti (100-a-0.4b-n1[d+e]) Cr (a-0.6b-n2[d+e]) V (b-n3[d+e]) X d T e    
       wherein 
 X is at least one or more other elements selected from the group consisting of Al, Ge, Ga, Si, Au and Pt,  
 T is at least one or more other elements selected from the group consisting of Nb, Ta, Mn, Fe, Al, B, C, Co, Cu, Ga, Ge, a lanthanoid metal, N, Ni, P, and Si, and  
 20≦a (at %)≦80;  
 b is within a range of 6±2 (at %);  
 0≦d (at %)≦20;  
 0≦e (at %)≦10 and  
 n1+n2+n3=1.  
 
     
     
         24 . The hydrogen storage metal alloy according to  claim 22 , wherein the structure comprises a mono-phase structure.