AM60镁合金Cr涂层制备及其耐腐蚀性研究

为了提高AM60镁合金的耐腐蚀性能,采用机械涂覆的方法在合金表面制备Cr涂层。通过XRD、视频显微镜、SEM、显微硬度分析等方法对表面涂层的物相、截面形貌、涂层的显微硬度等进行表征,利用电化学工作站对涂覆Cr前后的AM60镁合金的耐蚀性能进行分析。结果表明:AM60镁合金表面成功涂覆了Cr涂层,所制备涂层与基体结合致密,涂覆效果较好;同时,涂层的显微硬度高达到1 132 HV,较基体提高了1.96倍;球料比为10∶1和20∶1时,球磨时间为20 h和15 h时所制备的膜层耐腐蚀性能较好,和基体相比,所制备样品的自腐蚀电流密度均降低了3个数量级,自腐蚀电位均大幅提高,阻抗谱半径也均增加,在模拟海水中的耐腐蚀性能都得到明显改善。因此,在该实验条件下,Cr涂层的最佳制备工艺为:球料比为10∶1,球磨时间为20 h。

Preparation of Cr Coating on AZ31 Magnesium Alloy and Its Corrosion Resistance

To improve the corrosion resistance of AM60 magnesium alloy, Cr coating of the alloy was prepared by mechanical alloying. The microstructure, microhardness and corrosion resistance of AM60 magnesium alloy surface were analyzed by means of XRD, video microscopy, SEM, microhardness tester and an electrochemical workstation. The results showed that Cr coating with density was successfully prepared. There was a good interface bonding between Cr coating and AM60 magnesium alloy. Meanwhile, the microhardness of Cr coating reached to 1132HV, which was 1.96 times higher than that of the substrate. When the ball-to-material ratio is 15∶1 and 20∶1, and the ball milling time is 20h and 15h respectively, which the corresponding self-corrosion current density was all 3 order of magnitudes and the corresponding corrosion voltage was increased by 55% and 238%, respectively. Impedance value were all bigger than that of the substrate. The corrosion resistance of AM60 magnesium alloy in the simulated seawater was greatly improved; Under the experimental conditions, the optimal preparation parameter of Cr coating is as follows: the ball-to-material ratio is 10∶1 and milling time is 20h, resulting in obtaining the Cr coating with the best performance.