负相电压对城轨车体用6005A-T6铝合金MAO薄膜性能的影响

Effect of Negative-Phase Voltage on the MAO Film Properties of 6005A-T6 Aluminum Alloy for City Rail Car Body

为了提高城轨车体用6005A-T6铝合金表面的耐磨能力,通过对其实施微弧氧化处理的方式制得高耐磨性薄膜,分析了负相电压参数引起的微弧氧化层结构特征、硬度及其耐磨性的变化。结果表明:6005A-T6铝合金经过微弧氧化后在薄膜内形成了γ相氧化铝。薄膜形成了明显火山状结构,整体表面较为粗糙,形成了许多尺寸差异较大的微米孔洞以及大量熔融颗粒。薄膜包含了内部致密组织以及外部相对疏松的结构,存在4μm的致密层组织。对铝合金实施微弧氧化可以使硬度显著上升,当负相电压-100 V时,可以获得1265 HV的最高硬度。当负相电压在-100 V时,薄膜形成很小的摩擦系数并且较为稳定,表现出优异的耐磨性。MAO薄膜表现为白色条状的外观,观察到部分黑色块状组织,到达-100 V时试样中形成了更小的块状区域。

In order to improve the wear resistance of the surface of 6005 A-T6 aluminum alloy for city rail car body,the thin film with high wear resistance was prepared by micro-arc oxidation treatment,and the changes of structure characteristics,hardness and wear resistance of micro-arc oxidation layer caused by negative-phase voltage parameters were analyzed.Results showed that after micro-arc oxidation of the aluminum alloy 6005 A-T6,γ-aluminium oxide was formed in the thin film.The formed thin film had an obvious volcanic structure,the overall surface was relatively rough,forming many micron holes with different sizes and a large number of molten particles.The thin film contained the internal dense tissue and the external relatively loose structure,which had a 4μm dense layer tissue.Micro-arc oxidation increased the hardness of aluminum alloy significantly,and the highest hardness(1265 HV)was obtained when the negative-phase voltage was at-100 V.When the negative-phase voltage was at-100 V,the friction coefficient was small and relatively stable,showing excellent wear resistance.Besides,the MAO thin film presented the appearance of white strips,and some black lumpy tissues were also observed.Under the condition of-100 V,smaller lumpy areas were formed in the prepared sample.