N、Nb合金化对309S奥氏体不锈钢腐蚀性能的影响  

Effect of N and Nb Alloying on Corrosion Properties of 309S Austenitic Stainless Steel

作　　者：王聪 王春妮 刘后龙 刘星辰 李兰云[1] 宰伟 余中狄 WANG Cong;WANG Chunni;LIU Houlong;LIU Xingchen;LI Lanyun;ZAI Wei;YU Zhongdi(School of Materials Science and Engineering,Xi'an Shiyou University,Xi'an 710065,China;Xi'an Rare Metal Materials Research Institute Co.,Ltd.,Xi'an 710016,China)

机构地区：[1]西安石油大学材料科学与工程学院,西安710065 [2]西安稀有金属材料研究院有限公司,西安710016

出　　处：《表面技术》2024年第22期82-91,126,共11页Surface Technology

基　　金：预研项目(Y2102S);西安市博士后创新基地项目(RC2207)。

摘　　要：目的以高放废液封装容器材料309S奥氏体不锈钢为研究对象,通过N、Nb联合添加改善不锈钢在Cl~-环境中的耐蚀性能,并探究N、Nb元素对不锈钢耐蚀性能的影响机理。方法采用扫描电镜、X射线衍射、形状测量激光扫描系统、X射线光电子能谱等手段,对不锈钢的微观组织及钝化膜成分进行分析,从击穿电位、极化电阻及腐蚀形貌等方面揭示了N、Nb元素对不锈钢耐腐蚀性能的影响机理。结果N的添加可以促进含Nb钢中耐蚀的Nb(C,N)析出以及难溶的Nb_(2)O_(5)腐蚀产物形成。同时,部分N转化为NH_(3)/NH_(4)^(+),提高局部pH,有利于表面再钝化。因此,N、Nb联合添加的309S不锈钢展现出优异的耐蚀性能。相比商用309S不锈钢,添加0.17%(质量分数)N和0.45%(质量分数)Nb的不锈钢在3.5%(质量分数)Na Cl溶液中击穿电位由0.20 V提升至0.96 V,自腐蚀电流密度从2.529×10^(-7)A/cm^(2)减小到0.793×10^(-7)A/cm^(2)。6%FeCl_(3)-0.16%HCl(质量分数)溶液浸泡腐蚀120 h后,N、Nb联合添加的不锈钢点蚀坑数目最少,平均表面粗糙度(S_(a))、最大点蚀坑宽度(W_(max))和最大点蚀坑深度(D_(max))均最小,展现出良好的耐蚀性能;仅添加Nb不添加N的不锈钢其击穿电位略低于309S不锈钢,S_(a)最大,点蚀坑向纵深方向扩展严重。结论N、Nb联合添加能有效抑制点蚀坑的萌生与扩展,显著提高不锈钢耐腐蚀性能,而单独添加Nb效果较差。309S austenitic stainless steel is one of the candidate materials for the canisters to store high-level waste.However,the corrosion resistance of 309S austenitic stainless steel makes it difficult to meet a design life of 100 years in the groundwater environment containing a Cl-.The corrosion resistance of 309S austenitic stainless steel was improved by adding N and Nb,and the differences in microstructure and corrosion resistance of experiment steel with different N and Nb contents were compared and analyzed.The microstructure and passivation film composition of the stainless steel were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD),Shape Measurement Laser Microscopy System(SMLMS)and X-ray photoelectron spectroscopy(XPS).The effect of N and Nb on material corrosion resistance was discussed.Electrochemical tests were carried out at the Gamy-Reference 3000 workstation.A three-electrode system was used as an electrolytic cell.The potentiodynamic polarization curve of the sample was measured by the potentiodynamic method.After the open circuit potential stabilized,the test was performed at a scanning rate of 0.33 mV/s and a test interval of-1.0 to 1.5 V(vs.SCE).The impedance spectrum of the sample was measured by the potentiostatic method.The amplitude was 10 mV,and the test interval was 0.01~100 kHz.ZView fitted the impedance spectrum.The polarization curve results showed that the pitting electricity of 2#and 4#samples increased from 0.20 V of the original 1#sample to 0.50 V and 0.96 V after addition of N and Nb.The impedance spectra showed that the arc of capacitive reactance increased obviously after N and Nb were added.Corrosion loss tests were performed according to ASTM standard G31-72.The sample was cut into 24 mm×18 mm×3 mm,and then soaked in a container containing 6wt.%FeCl_(3)-0.16wt.%HCl solution at 35℃for 120 h.During the 120 h soaking period,after sampling,ultrasonic cleaning with 20vol.%HNO3 for 60 min was performed to remove the corrosion products.The surface roughness of 3#s

关 键 词：309S不锈钢 N、Nb联合添加 腐蚀性能 协同作用 

分 类 号：TG174[金属学及工艺—金属表面处理]