铁基渗硼强化粉末冶金材料的性能及渗层生长动力学研究  

Properties and Growth Kinetics of Boronized Layer of Boride Strengthened Fe-based Powder Metallurgy Material

作　　者：方慧敏[1,2] 张光胜 夏莲森[3] FANG Hui-min;ZHANG Guang-sheng;XIA Lian-sen(School of Mechanical Engineering,Anhui Technical College of Mechanical and Electrical Engineering,Wuhu 241000,China;School of Mechanical&Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China;School of Materials,Anhui Polytechnic University,Wuhu 241006,China)

机构地区：[1]安徽机电职业技术学院机械工程学院,安徽芜湖241000 [2]南京航空航天大学机电学院,南京210016 [3]安徽工程大学材料学院,安徽芜湖241006

出　　处：《表面技术》2020年第7期338-345,共8页Surface Technology

基　　金：国家自然科学基金(51575269);2017年安徽省高校自然科学研究重大项目及重点项目(KJ2017ZD50,KJ2017A756);2019年度安徽高校优秀青年人才支持计划(gxyq2019186)。

摘　　要：目的通过固体粉末渗硼法直接烧结铁基粉末冶金材料,制备具有渗硼层的试样。方法采用固体渗硼工艺对铁基粉末冶金材料在1123、1223、1323 K温度下渗硼处理3、5、7、10 h,采用光学显微镜及扫描电镜(SEM)观察了渗硼层的形貌,测定了渗硼层的厚度。用X射线衍射仪分析了渗硼层的物相组成,用摩擦磨损试验评估渗硼层的耐磨性,采用Rockwell-C粘附性试验评估渗硼层与基体的粘合强度质量。对渗层的生长动力学曲线进行拟合,得出渗层动力学曲线和厚度等值线图。结果试样的渗硼层厚度为35~183μm,1323 K条件下获得双相渗硼层(Fe_2B+FeB),1123 K及1223 K条件下获得单相渗硼层Fe_2B。试样在1223 K温度下渗硼处理5 h获得的渗硼层的耐磨性最佳,其粘合强度质量根据规范通过HF3等级认可。该试验中B元素的扩散激活能为164 kJ/mol。结论烧结温度和渗硼时间与渗层厚度关系密切,渗硼时间与渗层厚度的关系呈现出抛物线关系。厚度值的平方与渗硼时间符合阿瑞纽斯(Arrhenius)公式呈线性关系。渗硼层的显微硬度显著高于基体硬度,随时间的增加,渗层中出现较多的孔洞与疏松,渗硼层形状由明显的梳齿状逐渐变成不太明显的梳齿状,此情况在高温下更加明显。The work aims to prepare a specimen with a boronized layer by directly sintering Fe-based powder metallurgy material with solid powder boronizing method.Solid boronizing technology was used to treat the Fe-based powder metallurgy material at temperature of 1123,1223,and 1323 K for 3,5,7 and 10 h.The morphology of the boronized layer was observed with an optical microscope and a scanning electron microscope(SEM),and the thickness of the boronized layer was measured.The phase composition of the boronized layer was analyzed by X-ray diffractometer.The wear resistance of boronized layer was evaluated by the friction and wear test.The quality of the bonding strength between the boronized layer and the substrate was evaluated by the Rockwell-C adhesion test.The growth kinetics curve of the boronized layer was fitted to obtain the plot of the boronized layer kinetics curve and thickness.The thickness of the boronized layer of the specimen was 35~183μm.A bi-phase boronized layer(Fe2B+FeB)was obtained under 1323 K,and a single-phase boronized layer Fe2B was obtained under conditions of 1123 K and 1223 K.The specimen obtained the best wear resistance at 1223 K for 5 h and the quality of the bonding strength of boronized layer was approved by the HF3 grade according to the specifications.The diffusion activation energy of B atoms in this experiment was 164 kJ/mol.The sintering temperature and boronizing time are closely related to the thickness of the boronized layer,and the relationship between the boronizing time and the thickness of the boronized layer is in a parabolic form.The square of the thickness value and the boronizing time accord with the Arrhenius formula and have a linear relationship.The microhardness of the boronized layer is significantly higher than that of the substrate.With the increase of time,more holes and looseness appear in the layer,and the shape of the boronized layer gradually changes from an obvious comb-tooth shape to a less obvious comb-tooth shape,which is more obvious at high temperature.

关 键 词：铁基材料 粉末渗硼 扩散系数 扩散激活能 显微硬度 Rockwell-C附着力测试 

分 类 号：TG174.445[金属学及工艺—金属表面处理]