316L和Hastelloy C合金在不同温度循环废酸中的耐蚀性能

Corrosion Resistance of 316L Stainless Steel and Hastelloy C in Circulating Disposal Acid of Different Temperature

为了解316L和Hastelloy C合金在不同温度的循环废酸中的耐蚀性能,利用静态挂片试验、电化学试验和扫描电镜研究了2种合金在不同温度循环废酸中的腐蚀速率及形貌。结果表明:在50℃的循环废酸中,316 L和Hastelloy C合金均具有优异的耐蚀性,且耐蚀性相当;316L和Hastelloy C合金的腐蚀速率均随循环废酸温度的升高而增加,316L合金的增加缓慢,Hastelloy C合金的增加急剧;当温度由50℃升高到80℃时,循环废酸的氧化性增加,Mo含量较高的Hastelloy C合金在循环废酸中不能形成完整、致密的钝化膜,从而使其耐蚀性急剧下降。

Static coupon-hanging tests and electrochemical tests were conducted to investigate the corrosion rates o 316L stainless steel and Hastelloy C in circulating disposal acid o different temperature.The morphology of the corroded surface was observed with a scanning electron microscope.It was found tha both 316L stainless steel and Hastelloy C possessed excellen corrosion resistance in circulating disposal acid of 50 ℃,and their corrosion resistance in this case was similar.With the increase of temperature of circulating disposal acid,the corrosion rate of 316L stainless steel gradually rose,but that of Hastelloy C rose drastically therewith.When the temperature of the circula ting disposal acid rose from 50 ℃ to 80 ℃,the oxidizing capability of the disposal acid was enhanced.As a result,in the circulating disposal acid of 80 ℃,it was impossible for complete and compact passivation film to form on the surface of Hastelloy C with a higher Mo content,corresponding to drastically reduced corrosion resistance of the alloy thereat.