Mn含量对梯度多孔Mg-Mn合金微弧氧化膜组织与性能的影响

Effect of Mn content on microstructure and properties of micro-arc oxidation film of gradient porous Mg-Mn alloy

研究了Mn含量对梯度多孔Mg-Mn合金微弧氧化过程中电压-时间曲线、微弧氧化膜层显微组织、膜层厚度、物相组成以及耐腐蚀性能的影响。结果表明,随Mn元素含量的增加,微弧氧化电压-时间曲线中的起始电压U1、击穿电压U2和稳定电压U3均下降,但是当Mn含量超过2%后,U1、U2、U3均上升,随着Mn元素含量的增加,微弧氧化膜层厚度先降低而后增加。当Mn含量为2%时,梯度多孔Mg-Mn合金表面形成的氧化膜质量最好,孔隙细小、分布均匀,膜层厚度为39.6μm。结合XRD和EDS分析表明,微弧氧化处理后试样表面膜层由Mg2Si O4和Mg O两相组成。随着在模拟体液中浸泡时间的延长,添加2%Mn元素的梯度多孔Mg-Mn合金的质量损失最少,析氢量最低,耐腐蚀性最佳。

The effect of Mn content on voltage-time curves during micro-arc oxidation process, microstructure, thickness, phase composition and corrosion resistance of the oxidation films on Mg-Mn alloy surface was studied. The results show with increase of Mn content,initial voltage( U1),breakdown voltage( U2),stable voltage( U3) also decrease,but they all increase when Mn content is beyond 2%. With the increase of Mn content,the thickness of oxidation layers first decrease and then increase. The oxidation films of the thickness of 39. 5 μm have fine and uniform pores and best quality with the addition of 2% Mn. XRD and EDS analysis show there are Mg O and Mg2 Si O4phases in the oxidation films. Corrosion resistance measurement shows the amount of hydrogen evolution and mass loss are lower for the gradient porous Mg-2% Mn alloys with the increase of immersing time. The corrosion resistance of gradient porous Mg-2%Mn alloys is the best.