AZ31镁合金无铬阳极氧化新工艺

Environmentally Acceptable Process for Chromium-Free Anodization of AZ31 Magnesium Alloy

为了提高镁合金的耐腐蚀性能,采用直流阳极氧化工艺研究了一种新型无Cr环保型镁合金阳极氧化配方及工艺。溶液主要成分包含NaOH、Na3PO4、KF、铝盐和适量添加剂。结果表明,氧化膜主要由MgO和MgAl2O4组成;该环保型阳极氧化新工艺所获得的膜层的耐腐蚀性能等级为9级,优于传统的HAE工艺(8级),对AZ31镁合金能提供更有效的保护。

An environmentally acceptable chromium-free process for the anodizing of AZ31 magnesium alloy was developed,aiming at increasing the corrosion resistance of the Mg alloy.Thus the anodizing of the Mg alloy in a solution containing proper contents of NaOH,Na-3PO-4,KF,aluminous salt,and additives was performed using a direct current power source.The phase composition and microstructure of the resulting anodic oxidation coating were analyzed by means of X-ray diffraction and scanning electron microscopy,while its corrosion resistance was evaluated as well using salt-spray test.It was found that the target oxide coating was composed of MgO and MgAl-2O-4 and had better corrosion resistance than the similar anodic oxidation coating prepared on Mg alloy using traditional HAE process.