不锈钢在氯化物介质中的空泡腐蚀行为及机理

CAVITATION EROSION BEHAVIORS AND MECHANISM OF 1Cr18Ni9Ti STAINLESS STEEL IN CHLORIDE SOLUTION

利用空泡腐蚀试验仪,采用失重法、SEM及电化学方法,研究了1Cr18Ni9Ti不锈钢在氯化物介质中的空蚀行为及机理.结果表明:随着NaCl盐浓度的增大,空蚀速度增大;随着温度增加,空蚀速度先增大后减小,说明氯化物介质的腐蚀性对材料空蚀行为影响显著.极化曲线的测定表明,在不锈钢空泡腐蚀过程中,电极受阴阳极反应过程的混合控制.通过外加阴极电流,可以使材料空蚀速度显著降低,这表明在氯化物介质中,腐蚀电化学因素对材料的空蚀过程起重要作用.

In this paper,cavitation erosion behaviors and mechanism of 1Cr18Ni9Ti stainless steel in chloride solution were studied by weight loss,electrochemistry,and microscopic examination methods,with the aid of the self-made cavitation erosion apparatus.The results showed that cavitation erosion rates of stainless steel in chloride solution increase with chloride concentration increasing in neutral solution,and cavitation erosion rates also go up with the temperature of chloride solution increasing.However,the cavitation erosion rates subsequently decrease after the solution temperature further increasing above 50℃.It shows that corrosive effect of chloride solution on cavition erosion of materials is large.From the polarization curves of cavitation erosion of this stainless steel,it is seen that cavitation erosion process is mainly controlled by not only the anodic passivation but also cathodic oxygen diffusion process of electrode.After applying cathodic currents,cavitation erosion rates of stainless steel drop sharply.It shows that the corrosion electrochemical factor plays an important role in material cavitation erosion.The synergism effect between corrosion electrochemical and hydrodynamic factor results in the serious cavitation erosion.