多孔W骨架用特殊粉末的制备

Preparation of special powder for porous tungsten skeleton

采用多孔W颗粒粉末制备的高孔隙度钨骨架中可填充高体积分数的铜,从而在保证钨铜复合材料具有低膨胀系数的基础上进一步提高其热导率。该文作者在以WO3为原料配制的料浆中加入造孔剂碳酸铵((NH4)2CO3)和表面活性剂聚乙二醇(PEG),采用喷雾干燥?还原法制备多孔W颗粒粉末,并研究(NH4)2CO3、PEG的加入量以及WO3含量对W颗粒形貌的影响。使用pH计测量pH值和旋转粘度计测定料桨粘度,利用扫描电镜(SEM)和X射线衍射仪(XRD)分别对粉末的形貌和物相组成进行观察与分析。结果表明:料浆中(NH4)2CO3、PEG和WO3的质量分数分别为10%、4%和40%时,得到的多孔W颗粒孔隙度较高;前驱体为球形的WO3粉末时则可在820℃的氢气气氛中还原90min得到纯W相。

W-Cu composite is a promising material of electronic encapsulation. W skeleton with high porosity attributed to porous tungsten precursory powder can be filled with copper of high volume fi＇action, which would extremely improve the thermal conductivity of the W-Cu composite on the premise of low coefficient of thermal expansion. Therefore it is very significant to explore a new preparation process for the high porous tungsten skeleton. In the research of the present paper, porous tungsten particle was prepared by spray drying-hydrogen reduction with WO3 as precursory material, and the effects of the content of added （NH4）2CO3, PEG and WO3 on the morphology of tungsten particles were studied. In addition, the morphology and phase constitute of powder was investigated by scanning electron microscope（SEM） and X-ray diffraction（XRD） respectively. The results show that the relatively higher porosity of particles has obtained with 10% （NH4）2CO3, 4% PEG and 40% WO3, and pure W crystal is formed in case of that the precursor is spherical WO3 powder and reduces at 820℃ for 90 min in hydrogen atmosphere.