循环水中304不锈钢发生点蚀的Cl~-浓度阈值研究

采用电化学法研究了循环水中304不锈钢点蚀电位(Eb)、蚀孔深度、蚀孔数量与氯离子浓度的关系。结果表明,常温下304不锈钢的Eb总是随着氯离子浓度的增大而减小,当氯离子质量浓度小于800 mg/L时,增大氯离子浓度易导致点蚀敏感,而大于该值时增大氯离子浓度不会明显增大点蚀倾向;从蚀孔深度和表面蚀孔数量得出的304不锈钢点蚀倾向由大变小的氯离子质量浓度阈值为770 mg/L。

Study on the chloride ion concentration threshold value of the pitting corrosion of 304 stainless steel in circulating cooling water

The relationship between pitting corrosion potential(Eb) of 304 stainless steel in circulating cooling water and the pit depth and pit number with chloride ion concentration has been studied by electrochemistry.The results show that the Eb always reduces with the increase of chloride ions concentration at room temperature.The tendency of pitting corrosion increases when the chloride ion mass concentration is less than 800 mg/L.And,the pitting corrosion does not have obvious increase,when the chloride ion mass concentration is higher than 800 mg/L.The threshold value of chloride ion mass concentration of the pitting corrosion tendency of 304 stainless steel obtained by the depth and number of surface pits is 770 mg/L.