采用超声辅助工艺在A Z91D镁合金表面制得了镁铝水滑石(Mg6Al2 (OH)16CO3·4H2O)转化膜,通过扫描电镜(SEM)和X射线衍射(XRD)分析了膜层的表面形貌和成分,利用极化曲线和交流阻抗(EIS)来评价该转化膜对镁合金的防护作用,研究了超声波对膜层质量的影响规律.结果表明,超声辅助处理工艺能够有效地缩短成膜时间,但长时间处理会使膜层出现局部破裂.超声辅助酸碱浸泡2h试样(US1+1 h)表面形成了较为连续、致密的水滑石膜,该膜层能明显提高镁基体的自腐蚀电位,并减小其腐蚀电流密度,腐蚀速度约为镁基体的1/20.
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