锌铝铬膜的防腐性能与机理

Corrosion prevention characteristics and mechanism of zinc-aluminum-chromium coating

通过SEM ,XRD ,EDS ,盐腐蚀试验 ,热腐蚀试验和电化学测试等研究了锌铝铬膜的防腐蚀性能与机理。结果表明 ,该膜层耐中性盐腐蚀性能至少优于镀锌钝化层 4倍。至于锌铝铬膜层的抗腐蚀机理可能在于锌和铝粒子的电化学保护、铬的表面钝化和锌铝铬化合物保护层的屏蔽等作用 。

The anti-corrosion characteristics and mechanism of zinc-aluminum-chromium coating were studied by tests of salt immersion, salt spray and heat treatment test, and by examinations of electro-chemical impedance spectra, SEM, XRD and EDS. The results show that the coating is superior to electro-zinc plating in anti-corrosion. The corrosion prevention mechanism of zinc-aluminum-chromium coating may come from the controlled galvanic protection of zinc and aluminum particles, the passivation of the object surface by chromic acid, and the barrier effect of zinc, aluminum and chromium compound. The combination of the above effects provides superior anti-corrosion characteristics.