材料期刊网

用恒电位浸蚀方法在高压釜中研究了供货态316 L钢在尿素介质中发生非敏化态晶间腐蚀与电位区段的关系,并在常温硫酸溶液中研究了316 L钢非敏化态晶间腐蚀的发展过程及其与电位值的关系。结果表明,固溶态316 L钢在活化或活化—钝化过渡电位区仅产生全面腐蚀。而在过钝化电位区,既产生全面腐蚀,也产生晶间腐蚀。在过钝化电位区进行恒电位浸蚀时,在等电量条件下,随着浸蚀电位值升高,晶间腐蚀所占比例逐渐减小;在非等电量条件下,随浸蚀时间推移(即随浸蚀电量增加),晶间腐蚀深度和宽度都增加,腐蚀断面形态呈“V”字形。使用高纯不锈钢可以减轻非敏化态晶间腐蚀。

By using the potentiostatic etching method, the behavior of non-sensitized intergranular corrosion (IGC) for as-received 316L stainless steel (SS) at different potential regions were studied in autoclave containing urea solution. The propagation of non-sensitized IGC and the relation of IGC to potential values were investigated in sulfuric acid at ambient temperature. It is found that only general corrosion occurs for as-received 316L SS both in the active potential region and in the active-passive transition potential region, but both general corrosion and IGC occur simultaneously in the transpassive potential region. With potentiostatic etching in the transpassive region, IGC is deepened and broadened with increased etching electric quantities (with etching time), and the cross section of corroded specimen is in "V" shape. Under the condition of potentiostatic etching with equal electric quantities in the transpassive region, the nobler the etching potential, the greater will be the IGC rate (V_(IGC)) and the total corrosion rate(V_t), the less will be the ratio of IGC rate to total corrosion rate (V_(IGC)/V_t). The non-sensitized IGC of austenitic SS may be lightened by using high purity SS.