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本文研究了氮对316L奥氏体不锈钢耐蚀性影响及其作用机理。结果表明:适量的氮含量对316L钢耐均匀腐蚀,耐点蚀及耐敏化性能均有明显的改善。XPS表面膜分析表明,氮并不影响钝化膜的基本组成。氮主要是富集于钝化膜与基体的界面附近,有效地阻碍Cl~-等有害离子对钝化膜的侵蚀,同时,氮也提高膜中Cr的富集程度,增加钝化膜的耐蚀性。氮的N_(18)价态分析表明氮有可能和介质中H~+发生作用生成NH_4~+,从而促使蚀孔钝化。通过EPR法辅以金相、扫描电镜的观察,定量分析了氮对敏化程度的影响规律。AEM分析结果表明,经敏化处理后的试样,发生晶间腐蚀的主要原因是沿晶界析出了富Cr的M_(28)C_(?)并引起晶界贫Cr,氮的有益作用是阻碍了晶间碳化物的形核和长大,减小了贫Cr区体积,因而有效地提高了钢的抗敏化性能。
In this paper, the effect of nitrogen on the corrosion resistance of 316L austenitic stainless steel and its mechanism were studied. The results showed that the proper amount of nitrogen content had a significant improvement on the uniform corrosion resistance, pitting corrosion resistance and sensitization of 316L steel. XPS surface film analysis showed that nitrogen did not affect the basic composition of the passivation film. Nitrogen is mainly concentrated near the interface between the passivation film and the substrate, effectively hindering the corrosion of the passivation film by Cl ~ - and other harmful ions, and at the same time, nitrogen also increases the enrichment of Cr in the film and increases the resistance of the passivation film Erosive. Nitrogen N_ (18) valence analysis shows that nitrogen may interact with H_ + in the medium to generate NH_4 ~ +, which will lead to passivation of the pits. EPR method supplemented by metallography, scanning electron microscopy, quantitative analysis of the impact of nitrogen on the degree of sensitization. The results of AEM analysis showed that the main reason for the intergranular corrosion was the Cr (superscript 2 +) Cr (28) C precipitated along grain boundary and the Cr Hindered the nucleation and growth of intergranular carbides and reduced the volume of Cr-depleted zone, thus effectively improving the anti-sensitization performance of the steel.