镁合金环保型阳极氧化工艺研究

采用Na284O7，Na2SiO3，有机羧酸盐及有机胺等组成的环保型碱性电解液，对AZ91D镁合金的阳极氧化进行了研究．实验结果表明：在这种无铬、无氟、无磷的环境友好电解液中，镁合金表面可形成一层光滑致密、具有较高硬度和优良耐蚀性的阳极氧化膜．探讨了电解液中各组分在成膜过程中的作用及电解工艺参数对成膜过程和膜层性能的影响，研究表明：Na284O7为促进成膜、增加膜层厚度的主要物质；Na2SiO3具有细化膜层、改善膜层耐蚀性的作用；有机羧酸盐可以有效提高膜层的硬度；有机胺可有效抑制阳极发生弧光放电．另外峰值电流密度、电解液温度以及pH值对成膜过程和膜层性能也有明显的影响．

Research on Environmental-Friendly Anodizing Process for Magnesium Alloys

The anodizing of AZ91D Magnesium alloys in alkali electrolyte, which contains Na_2B_4O_7,Na_2SiO_3,organic carboxylic acid salt and amine, was investigated. In this environmental-friendly bath solution, which had no chromate, fluoride, phosphate and any injurious ingredients, a smooth film, which showed good micro-hardness and corrosion resistance, could be deposited on AZ91D. The influences of electrolyte components and the preparation parameters on the film-forming process as well as the properties of oxide film were discussed. Na_2B_4O_7 could accelerate the film-forming and increase the thickness of the oxidefilm; Na_2SiO_3 could make the oxide film smooth and improve the corrosion resistance; organic carboxylic acid salt could increase the hardness of the oxide film; ethanol amine could to a great extent restrain sparking to the high voltage anodization of magnesium alloys. In addition, the peak current density, the temperature and the pH value of the electrolyte had apparent effects on the film-forming process and the properties of the oxide film.