目的 提高镁合金的耐蚀性能。方法 通过在单一植酸转化膜基础上，利用植酸的强络合作用，在反应溶液中引入金属离子，获得新型高耐蚀性植酸转化膜层。通过正交实验、SEM、EDS和电化学方法，对新型植酸转化膜层的工艺配方、微观形貌、元素组成和耐蚀性进行分析。结果 正交试验研究得到了新型植酸转化膜层的最佳工艺参数为：25 g/L Mn(H2PO4)2+10 g/L植酸，反应温度95 ℃，反应时间10 min。在此工艺下，得到的膜层均匀，和未添加Mn离子的膜层相比，裂纹明显减小。EDS结果表明，膜层的主要元素为Mg、P、O、Mn、C，转化膜的成分可能是锰、镁与植酸形成的络合物。动电位极化曲线的实验结果表明，新型植酸转化膜可以极大地降低镁合金的腐蚀电流密度（Jcorr=0.337 ），对镁合金的保护效率为96.37%。结论 通过在植酸转化膜中添加Mn元素，不仅可以减小植酸膜层的裂纹宽度，还可以极大地提高镁合金的耐蚀性。

The work aims to improve the corrosion resistance of magnesium alloy. A new type of phytic acid chemical conversion coating with high corrosion resistance was obtained based on single phytic acid chemical conversion coatings by introducing metal ions into the reaction solution through the strong interaction of phytic acid. The process formula, microstructure, elemental composition and corrosion resistance of the new coating were analyzed by orthogonal experiment, SEM, EDS and electrochemical method. The optimal process parameters of the new phytic acid conversion coating obtained through orthogonal experiment included 25 g/L of Mn(H2PO4)2, 10 g/L of phytic acid, reaction temperature of 95 ℃ and reaction time of 10 min. The phytic acid coating prepared by the optimal process had a uniform surface and contained fewer cracks, compared with the coating without Mn ions. The EDS results showed that the main elements of the coating were Mg, P, O, Mn, and C. The composition was a complex of manganese and magnesium phytate. The results of the potentiodynamic polarization curves showed that the new coating could greatly reduce the self-corrosion current density (Jcorr=0.337 ) of the magnesium alloy, and the protection efficiency for the magnesium alloy was 96.37%. Adding Mn into the phytic acid conversion coating cannot only reduce the width of the phytic acid coating cracks, but also greatly improve the corrosion resistance of magnesium alloy.