功能梯度Ti(C, N)基金属陶瓷制备技术

Fabrication technology of functionally graded Ti(C, N)-based cermets

  • 摘要: 通过真空液相烧结制备出Ti(C,N)基金属陶瓷基体,并对基体表面进行双辉等离子渗碳处理。运用扫描电子显微镜(SEM) 、电子探针(EPMA)、X射线衍射(XRD)等分析手段对渗碳前后材料的显微组织形貌、成分分布以及物相组成进行分析。结果表明,双辉等离子渗碳后金属陶瓷表面富Ti、Mo、W、C、N元素,贫Ni。渗碳过程中表层高的碳活度驱使内部的Ti、Mo、W元素向外迁移,从而迫使Ni向内迁移。渗碳后,材料表层富硬质相,近表层富粘结相。渗碳处理使试样表层硬度得到提高,对横向断裂强度影响不大。

     

    Abstract: Ti(C,N)-based cermets were prepared by vacuum liquid sintering and then heat-treated by double-glow plasma carburization. The microstructures,compositional distribution and phase constitution of the as-sintered and carburized cermets were analyzed by scanning electron microscope (SEM),electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) technology,respectively. It is found that a surface zone enriched in titanium,molybdenum,tungsten,carbon and nitrogen,deficient in nickel is introduced by the double-glow plasma carburization. The high carbon activity in the surface region drives titanium,molybdenum and tungsten elements inside the substrate to diffuse outwards,and consequently,the nickel-rich binder is forced to transport inwards. After carburization,the hard phase enriches in the surface zone while the binder enriches in the near surface area. The surface hardness of the cermet is enhanced by the heat-treatment,while its transverse rapture strength (TRS) is hardly changed.

     

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