ZK60镁合金微弧氧化改性研究

在NaOH电解液中,对ZK60镁合金进行微弧氧化处理。研究了微弧氧化过程的电压-时间曲线、微弧氧化电流、氧化时间对微弧氧化膜层的显微形貌和厚度的影响,测试了氧化膜的耐蚀性能。研究结果表明:随着微弧氧化电流和时间的增加,表面膜层厚度增加,但膜层中的微孔直径增加,表面粗糙度增加,氧化膜质量降低。在NaOH电解液中,微弧氧化电流为3A、氧化3min后,ZK60镁合金表面形成的氧化膜质量最好,厚度约为19.8μm。XRD分析表明微弧氧化处理后试样表面膜层由MgO相组成。耐腐蚀测试表明微弧氧化后样品的质量出现先增加而后降低的现象,其失重和析氢量均比未微弧氧化样品少,同时溶液pH值变化较慢,这说明微弧氧化后样品的耐腐蚀性提高。

Study on Micro-Arc Oxidation Modification of ZK60 Mg Alloys

ZK60 Mg alloys were micro-arc oxidated in sodium hydroxide electrolyte. The voltage-time curves were analyzed and the effects of oxidation current and oxidation time on microstructure and thickness of micro-arc oxida- tion layer were studied. The corrosion resistance of oxidation layer was measured. The results show that, the thick- ness and roughness of layers increase and there are big pores in the layers with the increase of oxidation current and oxidation time. The quality of layers becomes poor. In sodium hydroxide electrolyte, after micro-arc oxidated at cur- rent of 3 A for 3 rain, the oxidation film quality is best with the thickness of 19.8μm. The oxidation film was con- sisted of MgO phase after micro-arc oxidation by XRD analysis. It was found that the weight of oxidated samples in- creased firstly and decreased later with micro-arc oxidation. But the weight loss, amount of hydrogen evolution and pH change are all less than those of the samples without micro-arc oxidation, which shows that the corrosion resist- ance of ZK60 Mg alloys is improved after micro-arc oxidation.