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La2O3掺杂纳米W粉致密化行为与性能

Densification behavior and performance of La2O3-doped W nanopowders

  • 摘要: 采用溶液燃烧合成法制备了La2O3掺杂纳米钨(W)粉,分析了La2O3掺杂纳米W粉的致密化行为及La2O3对纳米W粉致密化行为的影响,研究了烧结后合金的显微组织形貌、导热性能及显微硬度。结果表明,La2O3会显著抑制纳米W粉的致密化速度,纯W粉在1350 ℃烧结后的相对密度可达到96.2%,而La2O3掺杂纳米W粉在1500 ℃烧结后的相对密度仅为95.0%。在1500 ℃烧结后的La2O3掺杂W合金的晶粒尺寸为0.57 μm,比纯W粉烧结合金的晶粒尺寸小一个数量级,因此其导热性能也较纯W粉烧结合金有所降低,但是显微硬度得到显著提升。

     

    Abstract: The La2O3-doped W nanopowders were prepared by the solution combustion synthesis method. The densification behavior of the La2O3-doped W nanopowders and the effect of La2O3 on the densification of the W nanopowders were analysed. Meanwhile, the microstructure, thermal conductivity, and microhardness of the sintered alloys were also studied. The results show that, La2O3 can significantly inhibit the densification rate of W nanopowders. The relative density of the pure W powders sintered at 1350 ℃ can reach 96.2%, while that of the La2O3-doped W nanopowders sintered at 1500 ℃ is only 95.0%. The grain size of the La2O3-doped W alloys sintered at 1500 ℃ is 0.57 μm, which is one order of magnitude smaller than that of the pure W alloys. Therefore, the thermal conductivity of the La2O3-doped W alloys is lower than that of the pure W alloys, but the microhardness is significantly improved.

     

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