不锈钢着黑色工艺及着色机理

Technology and Mechanism of Black Coloring for Stainless Steel

介绍了一种不锈钢着黑色溶液的组成及工艺参数:NaNO367g/L,NH4NO367g/L,MnSO470g/L,H2SO4250mL/L,CrO340g/L,添加剂A20g/L,添加剂B40g/L,光亮剂钼酸铵1.5g/L,着色时间8～10min,着色温度95～100℃。讨论了该配方各组分的作用及其对黑色膜质量的影响,分析了着色发黑的可能机理是不锈钢基体的溶解形成大量的Me2+(Me代表Fe,Cr,Ni),金属溶液界面上的Me2+与Cr3+水解形成合金氧化膜沉积在基体表面上。电镜扫描和能谱结果显示膜层的厚度约为0.5631μm,膜层为块状结构,着色膜主要成分是Fe,Mn和Cr等元素,表明着色膜提高了不锈钢的耐磨性、耐蚀性。

An innovative chemical method of black coloring for stainless steel and the composition of the brightening solution was introduced. The optimum technique parameters are as follows:NaNO_3 67 g/L, NH_4NO_3 67g/L, MnSO_4 70 g/L, H_2SO_4 250 mL/L,CrO_3 40g/L, additive A (20 g/L,) additive B 40 g/L,brigtening reagent (NH_4)_2MO_4 1.5 g/L, the coloring time 810 min and the coloring temperature 95100 ℃. The effect of individual component on the quality of blackening film were studied. The probable mechanism underlying the blackening and brightening process is as follows: a large number of Me^(2+)(Me is Fe, Cr or Ni) are formed by the dissolving of the stainless steel and the oxide film precipitates on the bulk surface because of the hydration of Me^(2+) and Cr^(3+) on the interface between metal and solution. The film with a thickness of 0.563 1 μm can be obtained in the experiment. The microstructure of film is lump structure. According to energy dispersive spectra analysis, the main elements of coloring film are Fe, Mn, Cr and so on. The coloring film improves corrosion resistance and anti-abrasive of stainless steel.