Hydriding behavior of pseudobinary CaAl(2-x)M(x) (M=B, Si, 0<=x<=1) alloys

The hydriding behavior of pseudobinary CaAl(2-x)M(x) (M = B, Si, 0 less than or equal to x less than or equal to 1) alloys with the C15 Laves phase structure is examined in the search for new metal hydrides for hydrogen storage. The initial activation for hydriding proceeded at an H-2 pressure of 3 MPa and at temperatures between 300 and 400 degrees C without changing their phase structure or decomposing thermally. The CaAl1.8B0.2 alloy absorbed the largest amount of hydrogen among these alloys, forming CaAl1.8B0.2H0.6 at an H-2 pressure of 1 MPa at 60 degrees C. For alloys with compositions around CaAl(1.8)M(0.2), pressure plateaus were observed in the pressure-composition isotherms. Lattice contractions were also observed in these alloys.