摘要
目的对SS304在300 Pa不同温度下进行表面离子渗氮,研究渗氮层和SS304的耐蚀性。方法通过动电位极化曲线和交流阻抗谱分析SS304和渗氮层在3.5%Na Cl溶液中的耐蚀性,采取金相显微镜、SEM、XRD对渗氮层和SS304的表面形貌和相组成进行分析测试,采用显微硬度计和镜像显微镜对渗氮层和SS304的硬度和截面形貌进行分析测试。结果 SS304中有γ相和M相,400℃时渗氮层试样出现γN、Fe23N、Fe4N,大于450℃时,渗氮层试样出现了Fe23N、Fe4N、Cr N。渗氮层在3.5%NaCl溶液中,400℃时渗氮层的自腐蚀电流密度比SS304的小,大于450℃时,渗氮层的自腐蚀电流密度比SS304的小且随渗氮温度增加而逐渐增大;400℃时渗氮层的自腐蚀电位比SS304的大,大于450℃时,渗氮层的自腐蚀电位比SS304的大且随渗氮温度增加而逐渐降低;400℃时渗氮层表面的膜电阻比SS304的大,大于≥450℃时,渗氮层表面的膜电阻比SS304的小。结论渗氮层的耐蚀性随温度的升高而降低,400℃时渗氮层的耐蚀性比SS304的好,大于450℃时,渗氮层的耐蚀性比SS304的低;400℃时渗氮层生成氮扩大奥氏体（γN）,可大大增加耐蚀性,大于450℃时,渗氮层生成Cr N,耐蚀性减小。
The work aims to study corrosion resistance of nitrided layer and SS304 by performing surface ion nitriding to SS304 at different temperature at 300 Pa. The corrosion resistance of nitrided layer and SS304 in 3.5% Na Cl solution was analyzed by potentiodynamic polarization curve and electrochemical impedance spectroscopy. Morphology and phase composition of the nitrided layer and SS304 were analyzed and tested by ustilizing metalloscope, SEM and XRD. Hardness and cross-section morphology of the two were analyzed and tested by ustilizing microhardness tester and metallographic microscope. γ and M phases were present in SS304, γN, Fe23N and Fe4N were present in the nitrided layer sample at 400 ℃. Fe23N, Fe4 N and Cr N were present at 〉450 ℃. In the 3.5% Na Cl solution, self-corrosion current density of the nitrided layer was lower than that of SS304 at 400 ℃. At 〉450 ℃, it was also lower than that of SS304 and gradually increased as the nitriding temperature increased. The self-corrosion corrosion potential of the nitrided layer was higher than that of SS304 at 400 ℃. At 〉450 ℃, it was higher than the latter and gradually decreased as the nitriding temperature increased. At 400 ℃, membrane resistance of the nitrided layer was bigger than that of SS304; at ≥450 ℃, that was smaller. In conclusion, the corrosion resistance of the nitrided layer reduces as the temperature increases. The corrosion resistance of nitrided layer is superior to that of SS304 at 400 ℃ and lower than that of SS304 at 〉450 ℃. Nitrogen expanded austenite（γN） is produced in the nitrided layer at 400 ℃, significantly improving corrosion resistance of the nitrided layer while Cr N is produced at 〉450 ℃, reducing the corrosion resistance simultaneously.
出处
《表面技术》
EI
CAS
CSCD
北大核心
2016年第11期93-98,共6页
Surface Technology
基金
辽宁省自然科学基金项目(201202127)~~
关键词
SS304
离子渗氮
渗氮层
耐蚀性
SS304
ion nitriding
nitrided layer
corrsion resistance
