ZL101A阳极氧化局部过烧分析

Analysis on the defect of anodic oxide film on ZL101A aluminum alloy caused by locally too high current density

针对ZL101A铝合金材质的法兰盘在进行硫酸阳极氧化时表面随机出现斑块和黑色条纹的问题,借助光学显微镜(OM)、扫描电子显微镜(SEM)和能谱仪(EDS)等手段分析其形成机理。结果表明,缺陷出现的原因是阳极氧化过程中局部电流密度过大产生弧光放电,形成了许多细小的放电孔洞,而且因为发生弧光放电,导致异常区域的铝合金发生局部重熔,这在低温电解液中等同于淬火,所以造成了缺陷。

The formation mechanisms of plaque and black strip defects occurring during the anodic oxidation of ZL101A aluminum alloy flange in sulfuric acid was analyzed by optical microscopy(OM),scanning electron microscopy(SEM),and energy-dispersive spectroscopy(EDS).The results showed that the defects were caused by the arc discharge due to the local existence of high current density area,which resulted in the formation of tiny discharge cavities.The aluminum alloy in the defective area was remelted partially and solidified rapidly in the cold electrolyte during the anodic oxidation process,which was like a quenching process.