316L和347不锈钢在Solar Salt中的腐蚀行为研究

Corrosion behavior of 316L stainless steel and 347 stainless steel in solar salt

通过在500℃不同时间的静态腐蚀实验,研究了316L不锈钢和347不锈钢在Solar Salt(60%NaNO3+40%KNO3)中的腐蚀行为。通过跟踪2种不锈钢的质量变化,得到了这2种不锈钢的腐蚀动力学曲线。利用XRD和ICP-MS对熔盐物相和组分变化进行分析,利用XRD、SEM/EDS对不锈钢表面腐蚀产物物相、形貌和元素成分进行分析,最后结合熔盐与不锈钢二者的变化,分别讨论了316L和347不锈钢在Solar Salt中的相关腐蚀机理。腐蚀动力学曲线表明,316L和347不锈钢在500℃Solar Salt中均表现为腐蚀增重,随着腐蚀时间推进,316L不锈钢的增重呈现先增大后减小的趋势,347不锈钢的增重则一直增大。SEM/EDS的结果表明,347不锈钢更容易被氧化,同时347不锈钢中的Cr元素易发生溶出,相比之下,316L不锈钢在Solar Salt中的稳定性更好,即316L不锈钢的耐腐蚀性更强。

The static corrosion behavior of 316L stainless steel and 347 stainless steel at 500℃in Solar Salt(60%NaNO3+40%KNO3)was investigated via static corrosion test.Corrosion kinetic curves of 316L stainless steel and 347 stainless steel in molten salts at 500℃were obtained through measuring the weight changes of the specimens at each time intervals.XRD and ICP-MS were employed to characterize the phase and component of molten nitrate salts;XRD,SEM/EDS were used to characterize the morphology,composition and microstructure of the corrosion products on the surface and the cross section of corroded specimens.Finally,combining the changes of molten salt and stainless steels,the corrosion mechanism of 316L stainless steel and 347 stainless steel in Solar Salt was discussed respectively.Results showed that the corrosion behavior of 347 SS in Solar Salt at 500℃was characterized by mass gain.As time goes on,the trend of 316L stainless steel increased first and then decreased,while the trend of 347 stainless steel was on the increase.SEM/EDS showed that 347 stainless steel was more likely to be oxidized,while the chromium element in 347 was prone to dissolve,comparing to 316L stainless steel is better stability in Solar Salt,that is,316L stainless steel is more corrosion resistant.