TiC纳米线/Mo-Al2O3金属陶瓷的制备与电学性能

Preparation and electrical properties of TiC nanowires/Mo-Al2O3 cermet

  • 摘要: Mo-Al2O3金属陶瓷具有热震稳定性好、耐高温、低电阻等优点,已经作为特高压(UHVDC)运输过程中的核心部件。但由于电阻率可控性差、渗流阈值较高及机械强度低等缺点,严重制约了其在特高压运输中的广泛应用。采用碳化钛纳米线(TiCNW),制备了具有桥连结构的TiCNW/Mo-Al2O3陶瓷复合材料。研究了TiCNW、Mo与Al2O3之间构建的桥连结构,对金属陶瓷的电学性能和力学性能的影响规律,实现了陶瓷电阻率稳定的基础上的渗流阈值降低。当TiCNW含量为13wt%时,Mo-Al2O3金属陶瓷的渗滤阈值降低到10wt%,当TiCNW和Mo含量分别为8wt%和30wt%时,金属陶瓷弯曲强度和硬度可分别达到95 MPa和1283 kg/mm2,并观察到金属陶瓷桥联结构。研究结果对于制备高性能Mo-Al2O3金属陶瓷具有重要意义。

     

    Abstract: Mo-Al2O3 cermet has the advantages of good thermal shock stability, high temperature resistance and low resistance, and has been used as the core component in the process of ultra high voltage direct current (UHVDC) transportation. However, due to the poor controllability of resistivity, high seepage threshold and low mechanical strength, its wide application in UHVDC transportation is seriously restricted. TiCNW/Mo-Al2O3 ceramic composites with bridge structure were prepared by using titanium carbide nanowires (TiCNW). The bridge structure constructed between TiCNW, Mo and Al2O3 was studied, and the influence of the bridge structure on the electrical and mechanical properties of cermets was studied. The percolation threshold is reduced on the basis of stable resistivity of cermets. When the TiCNW content is 13wt%, the percolation threshold of Mo-Al2O3 cermet is reduced to 10wt%. When the TiCNW and Mo contents are 8wt% and 30wt%, respectively, the flexural strength and hardness of cermet can reach 95 MPa and 1283 kg/mm2, respectively, and the cermet bridging structure is observed. The research results are of great significance for the preparation of high-performance Mo-Al2O3 cermets.

     

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