304不锈钢无铬电解着色膜的制备及其性能

Preparation and Properties of Chromium-Free Electrolytic Coloring Coatings on Stainless Steel

现有的不锈钢着色工艺复杂、成本高,为简单化工艺、降低成本,采用恒直流供电方式对304不锈钢进行无铬体系和含铬体系电解着色。采用扫描电镜(SEM)、X射线光电子能谱仪(XPS)、电化学测试和显微磨损试验等对比分析了2种着色膜的显微结构和性能。结果显示:不锈钢无铬体系电解着色膜的耐蚀性与含铬体系相差不大、耐磨性较含铬体系电解着色膜差,装饰性优于含铬体系;2种电解着色膜都存在裂纹和凹坑,裂纹沿晶界生长,无铬体系电解着色膜的裂纹更少、更浅,膜层更均匀;无铬体系电解着色膜主要含O、Mo、C元素以及少量的Fe、Mn元素,Mo以正六价的MoO_3或Na_2MoO_4形式存在,Fe分别以正二价的FeOOH和正三价的Fe_2O_3形式存在;含铬电解着色膜中主要含有O、Cr、Fe元素及少量的Ni元素,其中Cr分别以正三价的Cr_2O_3和正六价的CrO_3形式存在,Fe分别以正二价的FeO和正三价的Fe_2O_3形式存在。

In this paper,the stainless steels were electrolyticly colored under direct current supply in chromium-free system and chromium system,respectively.The properties of two films were analyzed and compared by SEM,XPS,electro-chemical test methods and microscopic wear testing machine and other technical means.Results showed that the corrosion resistance of the electrolytic coloring film in chromium-free system was similar to that in chromium system,and the coloring film in chromium-free system had the poorer wear resistance while the better decorative property than that in chromium system.In both coatings,there existed the cracks and dents as well as the cracks developed along the grain boundary.For the chromium-free system,the cracks of the coating were less and more shallow,and the coating was more homogeneous.Electrolytic colored film in chromium-free system mainly contained 0,Mo and C,and a bit Fe and Mn.Mo existed in positive hexavalent(MoO_3 or Na_2MoO_4) and Fe existed in positive divalent(FeOOH) and positive trivalent(Fe_2O_3).Electrolytic colored film in chromium system mainly contained O,Cr and Fe and a bit Ni.Cr existed in positive trivalent(Cr_2O_3) and positive hexavalent(CrO_3),and Fe existed in positive divalent(FeO) and positive trivalent(Fe_2O_3).