纯铌表面渗碳层的结构与摩擦磨损性能  

Structure and Tribological Properties of Surface Carburized Layer on Pure Niobium

作　　者：吕绪明 张云汉 江涛[1,2] 李云飞 LYU Xu-ming;ZHANG Yun-han;JIANG Tao;LI Yun-fei(Research Institute of Physical and Chemical Engineering of Nuclear Industry,Tianjin 300180,China;Key Laboratory of National Defense Science and Technology for Particle Transport and Enrichment Technology,Tianjin 300180,China)

机构地区：[1]核工业理化工程研究院,天津300180 [2]粒子输运与富集技术国防科技重点实验室,天津300180

出　　处：《稀有金属与硬质合金》2023年第4期73-78,共6页Rare Metals and Cemented Carbides

基　　金：粒子输运与富集技术国防科技重点实验室开放课题研究基金项目(SYSJJ-22301)。

摘　　要：采用真空渗碳技术对纯铌进行表面渗碳处理,通过扫描电子显微镜、能谱分析仪和X射线衍射仪分析渗碳层的微观形貌、元素分布和物相结构,通过表面划痕、纳米压痕和摩擦磨损实验评价渗碳层与基体的结合强度、硬度和耐磨性能。结果表明:纯铌经1 400℃渗碳12 h后的渗层厚度约为37.8μm,由内、外两层组成,外层全部为NbC相,内层包含NbC和Nb_(2)C两种物相,致密均匀,没有孔洞和裂纹,与基体结合性能良好。通过渗碳极大地提高了纯铌基体的硬度和弹性模量,表面纳米硬度从1.8 GPa提高到23.5 GPa。与纯铌相比,与Si_(3)N_(4)摩擦副配对摩擦过程中渗碳层的摩擦系数从1.03降至0.62,比磨损率由21.6×10^(-5) mm^(3)/(N·m)降至1.12×10^(-5) mm^(3)/(N·m),耐磨性得到提高。纯铌表面出现严重的磨损,磨损机制为黏着磨损和磨粒磨损,而渗碳后的材料由于硬质相NbC的存在,仅发生轻微磨损,磨损机制为磨粒磨损。The pure niobium was subjected to surface carburization by vacuum carburizing technology.The microstructure,elemental distribution and phase structure of the carburized layer were characterized by SEM,EDS and XRD.And the bonding strength,hardness and wear resistance of the carburized layer and substrate were evaluated by surface scratches,nano-indentations and friction and wear tests.The results show that the thickness of the carburized layer on pure niobium after carburizing at 1 400 ℃ for 12 h is about 37.8 μm,and the formed carburized layer consists of inner and outer layers.The outer layer is entirely composed of NbC phase while the inner layer contains NbC phase and Nb_(2)C phase.The carburized layer is dense and uniform without holes and cracks,presenting good bonding performance with the substrate.The hardness and elastic modulus of the pure niobium are greatly improved by carburizing,with the surface nano-hardness increasing from 1.8 GPa to 23.5 GPa.Compared with pure niobium,the friction coefficient of the carburized layer decreases from 1.03 to 0.62 during the friction process with Si_(3)N_(4) friction pair,and the specific wear rate decreases from 21.6×10^(-5) mm^(3)/(N·m) to 1.12×10^(-5) mm^(3)/(N·m),indicating an improvement of wear resistance.Severe wear is observed on the surface of pure niobium with adhesive and abrasive wear mechanisms,while only slight wear appears on the carburized layer due to the presence of the NbC hard phase with the abrasive wear mechanism.

关 键 词：纯铌 碳化铌 真空渗碳 微观结构 耐磨性能 

分 类 号：TG147[一般工业技术—材料科学与工程]