研究了微量 Ｔｉ在 Ｍｌ（ＮｉＣｏＭｎＴｉ）５合金中的作用．结果表明，在铸态条件下，Ｔｉ几乎全部以 ＴｉＮｉ３第二相的形式在晶界析出，退火处理后 ＴｉＮｉ３相消失，但 ＳＥＭ和 ＥＤＳ表明 Ｔｉ取代了 ＡＢ５型化合物中 Ａ侧的稀土 Ｍｌ；而不是 Ｂ侧的 Ｎｉ．Ｔｉ在 Ａ侧的取代量以 ５％为宜．此时合金在铸态和退火态的放电容量都在 ３１０ ｍＡ·ｈ／ｇ以上．进一步提高取代量虽然会改善循环稳定性，但大大降低了放电容量．Substitutional effect of small amount of Ti in hydrogen storage electrode alloy Ml(NiCoMnTi)5 was systematically studied. The results show that Ti in the alloy is almost entirely separated out as a second phase of TiNi3 at boundary of the as-cast dendrite. After annealed, TiNi3 phase disappeared, but SEM and EDS analyses indicate that the partially substituted element by Ti is mishmetal Ml, not Ni in B side as expected, i.e. Ti is an A side substituent element. The optimal substitution amount is 5% (atomic fraction), with which the corresponding alloy, both as-cast and annealed, shows a high discharge capacity over 310 mA.h/g. If more Ti is added, a greatly decreased discharge capacity will be received with only a little increase of better cycle stability.国家自然科学基金资助项目59801008;; 国家863高新技术计划资助项目 715－004－006
