貯氫合金的循環(huán)穩(wěn)定性
( 1. 內(nèi)蒙古科技大學 材料學院， 包頭 0140101;
2. 鋼鐵研究總院 功能材料研究所， 北京 100081)
摘 要: 用鑄造及快淬工藝制備了La-Mg-Ni系(PuNi3型)La2Mg(Ni0.85Co0.15)9Bx (x=0～0.2)貯氫合金， 分析測試了鑄態(tài)及快淬態(tài)合金的微觀結(jié)構(gòu)與循環(huán)穩(wěn)定性， 研究了硼及快淬工藝對合金微觀結(jié)構(gòu)及電化學循環(huán)穩(wěn)定性的影響。 結(jié)果表明， 鑄態(tài)合金具有多相結(jié)構(gòu)， 包括 (La, Mg)Ni3相和LaNi5相， 一定量的LaNi2相及微量的Ni2B相, 經(jīng)大于15m/s淬速快淬處理后Ni2B相消失， 并且其它相的相對量隨淬速的變化而變化。 硼的加入提高了鑄態(tài)及快淬態(tài)合金的循環(huán)穩(wěn)定性， 但其作用機理完全不同。 合金的循環(huán)壽命隨淬速的增加而增加， 但快淬工藝對La-Mg-Ni系貯氫合金循環(huán)壽命的改善非常有限。
關(guān)鍵字: La-Mg-Ni系貯氫合金； 快淬工藝； 微觀結(jié)構(gòu)； 循環(huán)穩(wěn)定性
(PuNi3-type) hydrogen storage alloys prepared by casting and rapid quenching
GUO Shi-hai2, REN Jiang-yuan1, WANG Xin-lin2
（ 1. School of Materials, Inner Mongolia University of Science and Technology, Baotou 014010, China;
2. Department of Functional Materials Research, Central Iron and Steel Research Institute, Beijing 100081, China）
Abstract: The La-Mg-Ni system (PuNi3-type) hydrogen storage alloys La2Mg(Ni0.85Co0.15)9Bx (x = 0, 0.1, 0.2) were prepared by casting and rapid quenching. The microstructures and electrochemical cycling stabilities of the as-cast and quenched alloys were determined and measured. The effects of boron content and quenching rate on the microstructures and electrochemical cycling stabilities of the alloys were investigated. The results show that the as-cast and quenched alloys are composed of the (La, Mg)Ni3 phase (PuNi3-type structure), the LaNi5 phase and the LaNi2 phase. A trace of the Ni2B phase exists in the as-cast alloys containing boron, and after the as-cast alloys are quenched when quenching rate is more than 15m/s, the Ni2B phase in the alloys nearly disappears. The relative amount of each phase in the alloys changes with the variety of the quenching rate. The addition of boron enhances the cycle stability of the as-cast and quenched alloys, but the mechanism is completely different. The cycle lives of the as-quenched alloys increase with the increasing quenching rate, but the improvement of the rapid quenching treatment on the cycling stability of La-Mg-Ni system hydrogen storage alloys is very limited.
Key words: La-Mg-Ni system electrode alloy; rapid quenching technology; microstructure; cycling stability
