A black conversion process for stainless steel was introduced. The effects of temperature and main composition of coloring solution on conversion process were studied. The properties of black conversion film such as composition and resistance to wear, heat, and corrosion were analyzed. The results show that the optimal process conditions for black coloring on stainless steel are as follows: chromic anhydride 175 g/L, concentrated sulfuric acid 275 mL/L, additive A 225 g/L, and temperature 80 ℃. The proportion of chromic anhydride and sulfuric acid has influence on the color and uniformity of conversion film. As the content of additive A increases, the color of conversion film is grey, black and blue respectively. The conversion film mainly consists of Fe2O3 and Cr2O3, has a thickness of 0.478 urn, features deep blackening, excellent brightness, heat resistance and mechanical processing performance, and better corrosion and wear resistance than the stainless steel substrate.%介绍了一种不锈钢黑色转化工艺.研究了温度和着色液主要组分对转化工艺的影响,并对黑色转化膜的成分、耐磨性、耐热性、耐蚀性等性能进行分析.得到不锈钢着黑色的最佳工艺条件为:铬酸酐175 g/L,浓硫酸275 mL/L,添加剂A 225 g/L,温度80℃.铬酸酐-浓硫酸复配组成影响转化膜的色泽和均匀性.随添加剂A含量的增加,转化膜颜色依次为灰、黑、蓝.不锈钢黑色转化膜的主要成分是Fe2O3和Cr2O3,膜厚为0.478μm,膜层黑度深,光亮度、耐热性和机械加工性能优异,耐腐蚀性和耐磨性均优于不锈钢基体.
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