【摘要】 在磷酸钠-磷酸二氢铵-高锰酸钾体系中对镁合金进行化学转化处理.研究了磷酸钠、磷酸二氢铵、高锰酸钾、温度、时间和添加剂对转化膜性能的影响.通过对转化膜结构、成分及性能的测试评价,得到了性能较好的化学转化溶液配方:Na3PO4为5g.L-1,NH4H2PO4为15g.L-1,KMnO4为1g.L-1,添加剂(NH4)6Mo7O24为0.5g.L-1.由SEM可观察到转化膜的表面成"干枯河床"状.XRD和EDS检测表明,膜层的主要成分是Mg,Al12Mg17和无定形相,膜层表面主要有Mn,Mg,K,O和Al等元素组成.腐蚀实验和电化学测试表明,添加剂能够降低转化膜的腐蚀率,转化膜较基体的腐蚀电位正移了0.73V,提高了镁合金的耐蚀性.更多还原

【Abstract】 AZ91D magnesium alloy was treated by chemical conversion in electrolyte system including Na3PO4,NH4H2PO4,KMnO4 in this paper.Effects of Na3PO4,NH4H2PO4,KMnO4,additives,temperature and time on the corrosion rate of the chemical conversion coatings were investigated and the electrolyte subsequently was optimized.The optimal parameter was as follows:Na3PO4 5 g·L-1,NH4H2PO4 15 g·L-1,KMnO4 1 g·L-1,(NH4)6Mo7O24 0.5 g·L-1.XRD,EDS and electro chemistry measurements show that the coatings compositions mainly include Mg,Al12Mg17 and non-crystal structure.The corrosion current potential of the coating increase 0.73 V,and the self-corrosion current density decreased.The anticorrosion property of AZ91D magnesium alloy was improved greatly with chemical conversion coating.更多还原