A concept of two steps current-decreasing mode derived from constant current mode was developed to fabricate micro-arc oxidation (MAO) coatings on ZK60 Magnesium (Mg) alloy in a dual electrolyte system. The growth characteristics of coatings were analyzed by voltage-time curves, and the coating microstructures were characterized by scanning electron microscopy (SEM). Meanwhile, the roughness, corrosion behavior and microhardness of MAO coatings were investigated. The results showed that the MAO coatings exhibit a smooth and compact surface and have improved hardness and thickness, smaller roughness, uneven distribution of holes and even low electrical energy consumption. Such positive characteristics results in an improved corrosion resistance of MAO coatings. The coating produced under the two steps current mode of “1.2-0.6A” showed a smaller corrosion rate of 0.1559 g/m2h as compared to the counterpart produced under the other modes. The nanoscratch tests results showed that the coating fabricated by “1.2-0.6A” mode has strong bond strength with the substrate. Under this optimized mode, the MAO process also had the lowest energy consumption of 49.8 W·(dm2·μm)-1.

提出了从恒流模式导出两步电流减小模式的概念，以在双电解质系统中的ZK60镁（Mg）合金上制造微弧氧化（MAO）涂层。通过电压-时间曲线分析了涂层的生长特性，并通过扫描电子显微镜（SEM）表征了涂层的微观结构。同时，对MAO涂层的粗糙度，腐蚀行为和显微硬度进行了研究。结果表明，MAO涂层具有光滑而致密的表面，并具有改善的硬度和厚度，较小的粗糙度，不均匀的孔分布以及甚至较低的电能消耗。这种积极的特性可以提高MAO涂层的耐腐蚀性。在两步电流模式“ 1.2-0”下产生的涂层。与其他模式下产生的腐蚀速率相比，图6A”显示的腐蚀速率较小，为0.1559 g / m2h。纳米划痕测试结果表明，“ 1.2-0.6A”模式制备的涂层与底材具有很强的结合强度。在这种优化模式下，MAO工艺的最低能耗为49.8 W·（dm2·μm）-1。