Influence of the Anodization Process on Zamak 5 Corrosion Resistance

Abstract Squeeze casting is the most industrially advantageous process for producing zamak 5 parts. However, this process generates porosity defects in parts, compromising their corrosion resistance. Therefore, this work aims to minimize defects and improve zamak 5 corrosive performance through the anodizing process. For this purpose, zamak 5 was anodized in 300 mol.m-3 oxalic acid and analyzed by ATR-FTIR, SEM, wettability and EIS techniques. The anodizing process promoted the formation of oxalate and oxide layers of Zn and Al, thereby reducing porosity defects. Although the anodized layer has fragile behavior, being porous and permeable, the immersion time of anodized zamak 5 in NaCl forms corrosion products in the alloy that exhibit better protection.摘要：挤压铸造（Squeeze casting）是制备锌合金5号（zamak 5）构件的工业化优势工艺。然而，该工艺会在构件内部产生孔隙缺陷，损害其耐腐蚀性能。因此，本研究旨在通过阳极氧化工艺减少缺陷并提升锌合金5号的耐腐蚀性能。为此，研究人员将锌合金5号试样置于300 mol·m⁻³的草酸溶液中进行阳极氧化处理，并采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）、扫描电子显微镜（SEM）、润湿性测试及电化学阻抗谱（EIS）技术开展分析。结果表明，阳极氧化工艺可形成锌与铝的草酸盐层及氧化层，从而有效降低孔隙缺陷。尽管阳极氧化层质地较脆，且仍存在孔隙与渗透性，但经阳极氧化处理的锌合金5号在氯化钠（NaCl）溶液中浸泡时，其表面生成的腐蚀产物可提供更优异的防护效果。