中國(guó)有色金屬學(xué)報(bào)
ZHONGGUO YOUSEJINSHU XUEBAO
| 第18卷 第11期 總第116期 2008年11月 |
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文章編號(hào)：1004-0609(2008)11-2030-06
磁熱處理對(duì)La-Mg-Ni-Co合金微結(jié)構(gòu)與電化學(xué)性能的影響
趙顯久1，李 謙1，林根文1，周國(guó)治1, 2
(1. 上海大學(xué) 上海市現(xiàn)代冶金及材料制備重點(diǎn)實(shí)驗(yàn)室，上海 200072；
2. 北京科技大學(xué) 冶金與生態(tài)工程學(xué)院，北京 100083)
摘 要: 考察La0.67Mg0.33Ni2.5Co0.5合金分別在鑄態(tài)、熱處理及磁熱處理3種狀態(tài)下的微結(jié)構(gòu)及其電化學(xué)性能。通過XRD衍射及SEM分析貯氫合金的物相組成和電極合金循環(huán)后的形貌，研究Co部分替代Ni以及有無(wú)外加磁場(chǎng)下熱處理對(duì)合金微結(jié)構(gòu)與電化學(xué)性能的作用規(guī)律。結(jié)果表明：經(jīng)Co部分取代的La-Mg-Ni鑄態(tài)合金經(jīng)過50次循環(huán)后，放電容量保持率從64.46%提高到74.80%；經(jīng)磁熱處理后，La0.67Mg0.33Ni2.5Co0.5合金的最大放電容量為324.80 mA∙h/g，較常規(guī)熱處理合金的容量提高了10.59%，放電容量保持率為83.07%，其放電平臺(tái)更為寬廣且平坦；磁熱處理的引入進(jìn)一步降低貯氫合金電極的極化電阻，改善合金電極動(dòng)力學(xué)性能。
關(guān)鍵字: La-Mg-Ni型貯氫合金；磁熱處理；微結(jié)構(gòu)；電化學(xué)性能
Effects of magnetic-heat treatment on microstructure and electrochemical properties of La-Mg-Ni-Co alloys
ZHAO Xian-jiu1, LI Qian1, LIN Gen-wen1, CHOU Kuo-chih1, 2
（1. Shanghai Key Laboratory of Modern Metallurgy and Materials Processing, Shanghai University, Shanghai 200072, China;
2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China）
Abstract:The microstructure and electrochemical performances of La0.67Mg0.33Ni2.5Co0.5 hydrogen storage alloys treated by casting, heat treatment and magnetic-heat treatment were studied. The influence of the substitution of Co for Ni and heat treatment with and without magnetic field on the structures and electrochemical performances of La-Mg-Ni alloys were investigated by XRD and SEM. The results show that the retention of discharge capacity of as-cast La0.67Mg0.33Ni2.5Co0.5 alloy increases from 64.46% to 74.80% for as-cast La0.67Mg0.33Ni3.0 after 50 cycles. The maximum discharge capacity of La0.67Mg0.33Ni2.5Co0.5 alloy heat treated under magnetic field is 324.8 mA∙h/g, which is larger by 10.59% than that of La0.67Mg0.33Ni2.5Co0.5 alloy after conventional heat treatment. The retention of discharge capacity of the former is 83.07%. The discharge voltage platform of La0.67Mg0.33Ni2.5Co0.5 alloy after magnetic-heat treatment is more broadened and flatter. The magnetic-heat treatment reduces the polarization resistance and improves the electrochemical kinetic properties of alloy electrode.
Key words: La-Mg-Ni-based hydrogen storage alloys; magnetic-heat treatment; microstructure; electrochemical properties
