贮氢合金V3TiNi0.56Mx耐腐蚀性能研究

Investigation on the Corrosion Resistance of V3TiNi0.56Mx Hydrogen Storage Alloy in Alkaline Solution

摘要:

钒基固溶体贮氢合金在KOH电解质溶液中容易腐蚀，导致合金的电化学循环稳定性差，限制了钒基固溶体贮氢合金在Ni/MH电池中的应用。通过测试贮氢合金V3TiNi0.56Mx(M=Al、Cr; x=0.1、0.3)在KOH溶液浸泡过程中组织结构变化和腐蚀电位、交流阻抗谱等，研究了钒基固溶体贮氢合金V3TiNi0.56Mx的耐碱液腐蚀性能。结果表明：钒基固溶体贮氢合金在碱液中的腐蚀原因是作为导电集流体的TiNi第二相在KOH溶液中的不断溶解；在合金V3TiNi0.56中添加Al和Cr元素，可阻止合金中分布于晶界的TiNi第二相的溶解，使合金的腐蚀电位提高，从而提高钒基固溶体贮氢合金的耐碱液腐蚀能力。

Abstract:

Vanadium-based hydrogen storage alloys are easily corroded in KOH solution, which leads to their poor electrochemical cyclic durability in alkaline solution and limits their application in the Ni/MH battery. In this paper, the structure transformation of V3TiNi0.56Mx alloys during full immersion corrosion in alkaline solution was investigated; the corrosion potentials, the Tafel curves and the impedance spectra were tested for the V3TiNi0.56Mx alloys in alkaline solution. The results show that the corrosion of V3TiNi0.56Mx alloys in alkaline solution is caused by the continuous dissolve of the TiNi compound based phase as a micro-current collector, and the addition of alloy elements Cr and Al can prevent the dissolve of TiNi compound based phase, shift the alloy corrosion potential and improve the corrosion resistance of alloys in alkaline solution.