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用扫描电镜、透射电镜能谱和俄歇能谱等研究了尿素厂汽提塔内实际腐蚀部件的腐蚀形态和机理。结果发现:固溶态的316L 不锈钢发生了晶间腐蚀,并伴生全面腐蚀和晶粒脱落,因而晶间腐蚀不深;其晶界区并不贫铬但富集磷、硅,晶界磷含量比钢中平均含量高二个数量级;而同样介质条件下未遭受晶间腐蚀的固溶态00Cr25Ni22Mo2N 高纯不锈钢却未见磷、硅的晶界富集。故认为磷(硅)的晶界富集是固溶态316L 不锈钢在尿素生产介质中产生晶间腐蚀的重要原因之一.
The corrosion morphology and mechanism of the actual corrosive components in the stripper of urea plant were studied by scanning electron microscopy, transmission electron microscopy and Auger spectroscopy. The results show that the intergranular corrosion occurs in solid solution 316L stainless steel and it is accompanied with complete corrosion and grain detachment, so the intergranular corrosion is not deep. The grain boundary is not poor in chromium but enriched in phosphorus, silicon and phosphorus Which is two orders of magnitude higher than the average steel content. However, the solid solution state 00Cr25Ni22Mo2N high purity stainless steel without intergranular corrosion under the same medium conditions shows no enrichment of phosphorus and silicon grain boundaries. Therefore, it is considered that the grain boundary enrichment of phosphorus (silicon) is one of the important reasons for the intergranular corrosion of solid solution 316L stainless steel in urea production medium.