MgO纳米颗粒对AZ31B镁合金微弧氧化涂层耐磨和耐蚀性的影响

Effects of MgO Nanoparticles on Corrosion and Wear Behavior of Micro-arc Oxide Coatings Formed on AZ31B Magnesium Alloy

中文关键词: 镁合金 微弧氧化 纳米MgO 耐蚀性 耐磨性

英文关键词: magnesium alloy, micro-arc oxidation, MgO nanoparticles, corrosion resistance, wear resistance

中文摘要:

      为了进一步改善AZ31B镁合金的耐磨和耐蚀性能,采用微弧氧化技术且在电解液中添加质量浓度为4 g/L的MgO纳米颗粒,制备了氧化物陶瓷膜。采用扫描电子显微镜观察其表面和截面形貌,采用X射线衍射仪测试微弧氧化(MAO)膜的物相组成,利用电化学工作站,盐雾试验箱测试耐腐蚀性,利用球-盘磨损实验测试耐磨性。结果表明:添加MgO纳米颗粒后,膜层孔洞的填充,膜层成分中MgO含量的增加,使腐蚀电流密度降低至4.28×10-9 A/cm²；中性盐雾试验结果表明腐蚀以点蚀和裂纹的形式发生,MgO的嵌入使腐蚀点减少和内部致密层厚度增加,从而使2 N荷载、干摩擦条件下样品的摩擦系数和磨损率分别减小至0.228和1.39×10-5 mm³/(N·m),耐蚀性和耐磨性得到改善。

英文摘要:

      To further improve the corrosion and wear resistance of AZ31B magnesium alloy, the oxide ceramic coatings were fabricated through micro-arc oxidation, and MgO nanoparticles (4 g/L) were added into the electrolyte. The surface and cross-sectional morphology were observed by scanning electron microscopy. The phase composition was measured by X-ray diffraction. The corrosion resistance was tested by electrochemical workstation and salt spray test. The abrasion resistance was tested using pin on disk test. The results indicate that with addition of the MgO nanoparticles, the corrosion current density is reduced to 4.28×10-9 A/cm², due to the micropores are significantly sealed and the MgO, as one of the components of the coatings is increased. The results of neutral salt spray show that the corrosion takes place in the form of pitting and crack, and the deposition of MgO reduces the corrosion point. Under dry friction of 2 N, with the increase of the thickness of the inner dense layer, the friction coefficient and the wear rate decreased to 0.228 and 1.39×10-5 mm³/(N·m), respectively. The corrosion and wear resistance are effectively improved.