含铜430不锈钢在模拟生理盐水环境下的耐蚀性能研究

Study on Corrosion Resistance of 430 Stainless Steel Containing Copper under Simulated Normal Saline Environment

为研究含Cu 430不锈钢在生理盐水环境下的腐蚀行为,采用电化学测试方法研究了含Cu 430铁素体不锈钢在模拟生理盐水(质量分数0.9%NaCl)溶液中的耐蚀性能,同时,利用Mott-Schottky曲线和X射线光电子能谱(XPS)对钝化膜的半导体特性和表面成分进行了表征,并借助扫描电镜(SEM)观察了电化学腐蚀后的表面形貌。结果表明,在0.9%的NaCl溶液中,不含Cu和含1.57%Cu(质量分数)的430铁素体不锈钢表面均产生了钝化膜。与不含Cu相比,含1.57%Cu的不锈钢耐蚀性降低。Cu元素对430铁素体不锈钢钝化膜中Cr_(2)O_(3)的形成有抑制作用,从而提高了钝化膜中的缺陷密度。加入Cu元素后,430铁素体不锈钢点蚀坑主要分布在富铜相附近,富铜相破坏了钝化膜的连续性,致使耐蚀性下降,不锈钢表面形貌破坏程度增大。

In order to study the corrosion behavior of copper-containing 430 stainless steel in normal saline environment,the corrosion resistance of ferritic stainless steel containing Cu 430 in simulated physiological saline solution(0.9%NaCl,mass fraction,the same below)was studied using electrochemical testing methods.The semiconductor properties and surface composition of the passivation film were character-ized using Mott-Schottky curves and X-ray photoelectron spectroscopy(XPS),and the surface morphology after electrochemical corrosion was observed using scanning electron microscopy(SEM).Results showed that in 0.9%NaCl solution,passive films were formed on the surface of 430 ferritic stainless steel without Cu and with 1.57%Cu.Compared with stainless steel without Cu,the corrosion resistance of 1.57%Cu stainless steel was reduced.Because Cu element inhibited the formation of Cr_(2)O_(3)in the passivation film of 430 ferritic stainless steel,the defect density in the passivation film increased.Additionally,the pitting corrosion pits of 430 ferritic stainless steel were mainly distributed near the copper-rich phase after adding the copper element,and the copper-rich phase destroyed the continuity of the passive film,resulting in the decrease of corrosion resistance and the increase of surface morphology damage of stainless steel.