电解法逐层溶解铁素体不锈钢并测定表层和基体中铬和硅的含量

以待分析的铁素体不锈钢和碳棒分别作为阳极和阴极 ,用由阴离子交换膜隔开的三室电解池作为采样器 ,对该钢样进行逐层溶解 ,并用氧化还原滴定法测定每一层中铬的含量。经测定 ,厚度约为 0.0 3mm的表层中铬的平均含量为 7.82 % ,基体中铬的含量为 17.2 0 % ,另该表层中硅的含量为 1 6 9% ,基体中硅的含量为 0.0 774% ,即该不锈钢表层为贫铬富硅层。

Electrolytic dissolving ferritic stainless steel by layers and determination of chromium and silicon in the surface and the matrix of the stainless steel

The ferritic stainless steel to be analyzed and carbon rods were used as anode and cathode, respectively. The dissolver was a triple-chamber electrolyser with the membrane placed between the chambers. The stainless steel sample was dissolved by layers, and chromium content of each layer was determined by the redox titration. The average chromium content of the surface layer about 0.03 mm thick is 7.82%, and that of the matrix of the steel is 17.20%. Silicon contents of the surface layer and the matrix are 1.69% and 0.0774%, respectively. That is to say, the surface of the ferritic stainless steel is a lager of poor chromium and rich silicon.