模拟冷却水中304不锈钢的耐蚀性影响因素研究

用电化学方法研究了Cl^-、S^2-、NO3^-、温度以及某电厂水质稳定剂对304不锈钢耐蚀性的影响。极化曲线表明：在[Cl-]／[SO4^2-]约为0．56时，点蚀电位开始下降，并随着Cl-浓度的增大逐渐降低；S2-的加入使钝化电流显著增大；NO3-浓度增加使点蚀电位逐渐升高；溶液温度的提高使点蚀电位降低，钝化电流也有所增大，钝化膜的耐蚀性降低;实验表明采用的某厂水质稳定剂可引起304不锈钢点蚀电位的下降。Mott-Schottky图显示S2-浓度的增加使体现p-型半导体(氧化铬)性质的直线段发生较大变化，说明硫离子影响了铬氧化物的性质。

Influence Factors on Corrosion Resistance of 304 Stainless Steel in Simulated Cooling Water

Corrosion resistance of 304 stainless steel was studied in simulated cooling water containing chloride, sulfide, nitrate and water stabilizer at various concentrations by using polarization curves and Mott-Schottky plots. Results showed that while [Cl- ]/[SO42-] ratio was approx 0.56, the pitting corrosion potential began reducing and gradually decreased with the increase of Cl- concentration. The passivity current increased greatly with the addition of sulfide ion. The pitting potential became more positive with the increase of nitrate concentration. Raise of solution temperature resulted in the decrease of the pitting potential and the corrosion resistance of passivating film. The water stabilizer used in a plant made the pitting potential of 304 stainless steel decreased. Mott-Schottky plots indicated that sulfide affected the semiconductor property of passive films.