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

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