Phytic acid (PA) and 3-aminopropyltrimethoxysilane (APTMS) were selected as organic additives and respectively doped into Na₂SiO₃-NaOH electrolyte to prepare ceramic coatings on AZ31B Mg alloys by Plasma Electrolytic Oxidation (PEO) method. The influences of two additives on corrosion resistance of the PEO coatings were compared. The microstructure, composition and corrosion resistance of the PEO coatings were examined by SEM, EDX, XPS, XRD, potentiodynamic polarization test and EIS measurement. The results indicated that each additive increased both the coating thickness and corrosion resistance. However, the PA-doped PEO coating achieves larger thickness but exhibits worse corrosion resistance than the APTMS-doped PEO coating due to larger pore size and looser microstructure.

中文翻译：

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PEO法比较植酸和硅烷助剂对镁合金陶瓷涂层耐腐蚀性能的影响

以植酸(PA)和3-氨基丙基三甲氧基硅烷(APTMS)为有机添加剂,分别掺杂到Na ₂ SiO ₃ -NaOH电解液中,采用等离子电解氧化(PEO)法制备AZ31B镁合金陶瓷涂层。比较了两种添加剂对PEO涂层耐腐蚀性能的影响。通过SEM、EDX、XPS、XRD、动电位极化测试和EIS测量对PEO涂层的微观结构、成分和耐腐蚀性进行了研究。结果表明，每种添加剂都增加了涂层厚度和耐腐蚀性。然而，PA 掺杂 PEO 涂层的厚度较大，但由于孔径较大且微观结构较松散，因此其耐腐蚀性比 APTMS 掺杂的 PEO 涂层差。