纳米W粉阶段碳化制备纳米WC粉的工艺及机制研究
发布时间：2019-04-26 07:45
【摘要】：以平均粒径40 nm的W粉为原料,采用"预碳化+二段碳化"的阶段碳化工艺制备出平均粒径为82 nm的近球形WC粉。利用X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、BET比表面积分析仪等测试方法,分别对碳化产物的物相组成、形貌和粒径大小进行表征。研究了不同预碳化温度和二段碳化温度对WC粉粒径和形貌的影响,并对阶段碳化的机制进行了讨论。结果表明,在800~1000℃范围内,WC粉的平均粒径随预碳化温度升高呈先减小后增大的变化趋势,在900℃达到最小值。WC粉的平均粒径随二段碳化温度升高而增大,当二段碳化温度高于1250℃时,WC粉的平均粒径显著增大。碳化过程中WC颗粒的长大主要是由碳化初期纳米W颗粒的烧结合并引起的。低温预碳化能够在W粉颗粒表面形成一定厚度的WC层,阻碍W粉颗粒发生烧结合并,从而有效抑制WC粉的长大。阶段碳化制备纳米WC粉的最佳工艺为:预碳化温度900℃,二段碳化温度1150~1200℃。
[Abstract]:Using W powder with average particle size of 40 nm as raw material, the near spherical WC powder with average particle size of 82 nm was prepared by the stage carbonization process of "pre-carbonization two-stage carbonization". The phase composition, morphology and particle size of carbonized products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), BET specific surface area analyzer). The effects of different pre-carbonization temperature and two-stage carbonization temperature on the particle size and morphology of WC powder were studied, and the mechanism of stage carbonization was also discussed. The results show that the average particle size of WC powder decreases first and then increases with the increase of pre-carbonization temperature in the range of 800 鈩，
本文编号：2465879
[Abstract]:Using W powder with average particle size of 40 nm as raw material, the near spherical WC powder with average particle size of 82 nm was prepared by the stage carbonization process of "pre-carbonization two-stage carbonization". The phase composition, morphology and particle size of carbonized products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), BET specific surface area analyzer). The effects of different pre-carbonization temperature and two-stage carbonization temperature on the particle size and morphology of WC powder were studied, and the mechanism of stage carbonization was also discussed. The results show that the average particle size of WC powder decreases first and then increases with the increase of pre-carbonization temperature in the range of 800 鈩，
本文编号：2465879
本文链接：https://www.wllwen.com/guanlilunwen/gongchengguanli/2465879.html
