不同含量硼酸镁晶须增强AZ91D镁基复合材料在Na_2CO_3溶液中的电化学腐蚀行为

Electrochemical Corrosion Behavior of Magnesium Borate Whisker-Reinforced AZ91D Magnesium Matrix Composites in Sodium Carbonate Solution

目前,国内外对晶须增强镁基复合材料的电化学腐蚀行为鲜有报道。采用真空气压渗流技术制备了硼酸镁晶须增强AZ91D镁合金,采用电化学工作站测试了其在5%Na2CO3溶液中的开路电位和动电位极化曲线,采用扫描电镜及X射线能谱仪分析了镁基复合材料的微观腐蚀形貌及成分,研究了晶须体积分数对其耐腐蚀性能的影响。结果表明:随着晶须体积分数的增加,AZ91D镁基复合材料的耐腐蚀性逐渐提高,镁基复合材料表面生成了一层活跃的钝化膜,对基体起到了一定的保护作用。

Vacuum pressure infiltration technique was adopted to prepare AZ91 D Mg-matrix composites reinforced with magnesium borate whisker.The open circuit potential and potentiodynamic polarization curves of as-prepared composites in 5%Na_2CO_3 solution were measured with an electrochemical workstation.The corroded surface morphology of the composites was analyzed by scanning electron microscopy and energy dispersive spectrometry.Furthermore,the effect of the content(volume fraction) of magnesium borate whisker on the corrosion resistance of the composites was investigated.Results showed that the corrosion resistance of the Mg-matrix composites tended to rise gradually with increasing volume fraction of the magnesium borate whisker.This was because an active passivation film was formed on the surface of the composites to protect the Mg substrate to some extent.