Mg0.9Ti0.1Ni0.85Co0.15合金的石墨粉及镍粉球磨表面包覆性能

选用非晶态的Mg0.9Ti0.1Ni0.85Co0.15合金粉末与石墨粉及镍粉进行球磨表面包覆。SEM分析结果表明,己包覆石墨和镍粉的合金表面上吸附着一层小的颗粒,形成薄层将原来的合金表面包覆起来。使用XPS分析了合金表面元素。结果表明,包覆石墨粉后,合金表面碳元素的质量分数和原子分数均增加,Mg的质量分数从22.74%减小至22.23%,原子分数从36.43%减小到32.94%,从而减小了Mg在碱液中的腐蚀几率,提高合金的抗腐蚀性能;包覆镍粉后,合金表面Ni的质量分数由59.89%增加到60.04%,原子分数由40.63%增加到41.02%,形成合金表面富Ni的保护层,提高了合金的抗腐蚀性能。充放电循环测试表明,循环30周后,包覆石墨粉的合金电极容量保持率为32.05%,包覆镍粉的合金电极容量保持率为41.26%,而未包覆的电极容量保持率仅为17.88%。合金电极极化曲线测试结果表明,石墨或镍粉的包覆提高了Mg0.9Ti0.1Ni0.85Co0.15合金电极的循环稳定性和在KOH碱液中的抗腐蚀性能。

Characteristics of Mg0.9Ti0.1Ni0.85Co0.15 Alloy Coated with Graphite and Nickel Powder by Surface Ball Milling

Amorphous Mg0.9Ti0.1Ni0.85Co0.15 alloy was coated with graphite and nickel powder by ball milling.SEM indicated that there was a graphite or nickel thin layer on the surface of the alloy.X-ray energy spectrum analysis showed that after coated with graphite powder,the C content at the surface of the alloy increased,and the mass and atomic contents of Mg decreased from 22.74% to 22.23%,and from 36.43% to 32.94%,respectively,which decreased the corrosion probability of Mg in alkali solution;after coated with nickel powder,the mass and atomic contents of Ni at the surface of the alloy increased from 59.89% to 60.04%,and from 40.63% to 41.02%,respectively, which indicted that a nickel-riched layer was formed.This nickel-riched layer can protect the alloy from corrosion in alkali solution.Charge-discharge cycle tests showed that after 30 charge-discharge cycles,the capacity retained for the graphite coated alloy,the nickel coated alloy,and the uncoated alloy was 32.05%,41.26% and 17.88%,respectively.This indicates the graphite coating and the nickel powder coating can increase the cycle stability.Polarization curves showed the antico-rrosion characteristic of the Mg0.9Ti0.1Ni0.85Co0.15 alloy electrode in KOH solution was improved by graphite or nickel coated.