摘要
对3Cr13钢在450℃氨气和氨氮混合气氛中分别渗氮4、8和12 h后的渗氮层进行了对比。利用光学显微镜、显微硬度计、X射线衍射仪、电化学工作站对渗氮层截面显微组织、显微硬度、相组成以及耐蚀性进行了表征。氨气渗氮层由化合物层和白亮层组成,而氨气和氮气混合气氛渗氮层中没有出现白亮层。氨气渗氮12 h后,渗氮层的表面硬度为1050.0 HV0.05;表面化合物层主要相为ε-Fe_(2-3)N,次要相为γ'-Fe_(4)N,出现了少量的CrN,白亮层相组成为γ'-Fe_(4)N;渗氮后极化曲线钝化区变宽,自腐蚀电流密度减小,耐蚀性提高。氨氮混合气氛渗氮12 h后,渗层的表面硬度为998.0 HV0.05;气氛中N浓度升高,渗氮8 h后CrN含量增加,次要相由氨气渗氮8 h的γ'-Fe_(4)N变为CrN;随着渗氮时间延长至12 h,渗层的自腐蚀电流密度降低,钝化区略有变宽,耐蚀性略有提高。
Nitrided layers on the 3Cr13 steel after nitriding for 4,8 and 12 h in ammonia and in(ammonia+nitrogen)mixed atmosphere respectively at 450℃were compared.The cross section microstructure,microhardness,phase composition and corrosion resistance of the nitrided layers were characterized by metallographical microscope,microhardness tester,X-ray diffractometer and electrochemical workstation.The nitrided layer obtained in ammonia is composed of a compound layer and a bright white layer.However,there is no bright white layer in the nitrided layer obtained in ammonia and nitrogen mixed atmosphere.The surface hardness of the nitrided layer(12 h)in ammonia is 1050.0 HV0.05.After ammonia nitriding,the compound layer's main phase isε-Fe_(2-3) N,the secondary phase isγ'-Fe_(4)N,a small amount of CrN appears,and the phase composition of the bright white layer isγ'-Fe_(4)N.After nitriding in ammonia,the passivation zone of the polarization curve widens,the self-corrosion current density decreases and the corrosion resistance increases.The surface hardness of the nitrided layer(12 h)in ammonia and nitrogen mixed atmosphere is 998.0 HV0.05.Because of the increase of nitrogen concentration in the mixed atmosphere,the CrN content increases in the nitride layer after nitriding for 8 h,and the secondary phase transforms fromγ'-Fe_(4)N,which is secondary phase after nitriding in ammonia for 8 h,to CrN.The self-corrosion current density of the nitrided layer decreases when the nitriding time prolongs to 12 h in ammonia and nitrogen mixed atmosphere,the width of the passivation zone widens,and the corrosion resistance slightly improves.
作者
李芮
由园
闫牧夫
闫纪红
陈宏涛
王超会
刘东静
洪霖
Li Rui;You Yuan;Yan Mufu;Yan Jihong;Chen Hongtao;Wang Chaohui;Liu Dongjing;Hong Lin(School of Materials Science and Engineering,Qiqihar University,Qiqihar Heilongjiang 161006,China;National Key Laboratory of Metal Precision Thermal Processing,School of Materials Science and Engineering,Harbin Institute of Technology,Harbin Heilongjiang 150001,China;School of Mechanical and Electrical Engineering,Harbin Institute of Technology,Harbin Heilongjiang 150001,China;School of Materials Science and Engineering,Harbin University of Science and Technology,Harbin Heilongjiang 150040,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2021年第11期120-125,共6页
Heat Treatment of Metals
基金
国家自然科学基金(51401113)
黑龙江省自然科学基金(E2016069)
黑龙江省博士后资助项目(LBH-Z16061)
黑龙江省省属高等学校基本科研业务费科研项目(135309504)。
