不锈钢在海水中的耐蚀性与腐蚀电位的关系

A STUDY ON RELATIONSHIP BETWEEN CORROSION RESISTANCE AND CORROSION POTENTIAL OF STAINLESS STEELS IN SEAWATER

研究了 7种不锈钢在 4个试验站的海水中浸泡 1 80天的腐蚀电位特性 ,其中 5种不锈钢还进行了长达 4年的暴露试验。钝化能力强的不锈钢的海水腐蚀电位随浸泡时间向正变化 ,其腐蚀电位趋于稳定的时间较长 ,稳态腐蚀电位的波动较大 ;钝化能力较弱的不锈钢则相反。不同钢种的不锈钢在海水中的稳态腐蚀电位可以相差很大 ,在青岛、舟山和榆林 ,2Cr1 3和HRS 3间的稳态电位相差 0 .8V以上。不锈钢在海水中的稳态腐蚀电位较正 ,其耐蚀性较好 ;稳态腐蚀电位较负 ,其耐蚀性较差。

Corrosion potential of stainless steels immersed in seawater at four test sites in China for 180 days and corrosion data for 4 years were examined. Relationships between corrosion potential and seawater corrosion resistance of stainless steels were discussed. For stainless steels with high possivation tendency in seawater, their corrosion potential shifted toward positive with time, longer time was needed for the potential to become steady, and greater potential fluctuation was observed. The stainless steels with poor possivation tendency exhibited contrary results. Difference between steady potential of various stainless steels might be significant.At Qingdao, Zhoushan and Yulin,the variance of corrosion potential between 2Cr13 and HRS 3 reached over 0.8V. The order of steady corrosion potential of stainless steels from possitive to negative was consistent with their corrosion resistance in seawater. Stainless steels with relatively positive steady potential were corrosion resistant and vice versa. Thus, corrosion resistance of stainless steels in seawater could be evaluated on the basis of corrosion potential measurements.