HYDROGEN-OCCLUDING ALLOY WITH LOW COBALT CONTENT

摘要

A hydrogen-occluding alloy which has an extremely low cobalt content and can retain output characteristics (especially pulse discharge characteristics), activity (degree of activity), and life characteristics on a high level. A hydrogen-occluding alloy having an alloy composition represented by the general formula MmNi_aMn_bAl_cCo_d or MmNi_aMn_bAl_cCo_dFe_e is produced by weighing and mixing raw materials for the hydrogen-occluding alloy so as to result in a composition in a given range and regulating the production method or production conditions so that both the a-axis length and the c-axis length of the crystal lattice to be formed are in given ranges and that the equilibrium hydrogen pressure is 0.06 MPa or lower. Although an a-axis length of 499 pm or longer and a c-axis length of 405 pm or longer suffice for the crystal lattice, the a-axis length and c-axis length are more finely specified according to values of ABx. Thus, the hydrogen-occluding alloy can have high durability.