5A05铝合金黑色氧化膜的结构及耐蚀性能

用两步化学氧化法在铝合金表面获得了黑色氧化膜。利用全浸渍腐蚀试验及电化学极化曲线评价了膜的耐蚀性能,利用扫描电子显微镜观察膜的表面形貌,采用能量散射谱(EDS)测定膜的成分。结果表明:铝合金的黑色氧化膜具有网块状结构,膜层主要由O、Al、Mn、Co、Cr五种元素所组成,未经封闭的铝合金氧化膜的耐蚀性能很差,而经重铬酸钾封闭后,耐蚀性大为提高。

Microstructures and Anticorrosion Property of Black Oxidation Film on 5A05 Aluminium Alloy

Black oxidation film was obtained on Aluminium Alloy by two-step oxidation. The anticorrosion prop-erties of the film were evaluated by neutral salt spray tests and electrochemical polarization curve. The morphology of the film was studied by scanning electron microscope. The composition of oxidation film was determined by EDS. This experiment result indicated that the oxidation film coatings had large lumps with lots of crackles by SEM experiments and that the oxidation film consisted of oxygen, aluminum, manganese, cobalt and chromium and that the treated Al without sealing had a lower corrosion resistance in 3.5% NaCl solution, but the samples sealed by K_2Cr_2O_7 has a good corrosion resistance in 3.5% NaCl solution.