扩散阴极用纯钨棒制备工艺的研究

Study on Preparation of Pure Tungsten Rod for Diffusion Cathode

本文以中颗粒钨粉为原料,首先采用射流分级技术进行粒度调控,之后经冷等静压压制成形、氢气高温烧结得到多孔纯钨棒,再对其进行渗铜、机加工及去铜处理,制备出多孔钨基体。结果表明:较之原料钨粉,分级钨粉粒度分布变窄、振实密度明显增加,说明其具有更好的颗粒堆垛性能;随着烧结温度的提高,分级钨粉压制棒坯的孔隙度由1900℃的22.8%线性降低至2050℃的17.8%,2000℃烧结钨渗铜材料的抗拉强度R_m达到864 MPa,去铜后压汞法通孔孔隙度19.85%、平均孔径1.39μm,可用于高可靠扩散式钡钨阴极的制造。

The medium-sized tungsten powder was used as raw material.Firstly the particle size of tungsten powder was modulated by fluidic classification,and then porous tungsten sintered rod was obtained via cold isostatic pressing and hydrogen sintering in high temperature;followed by copper infiltration,machining and copper removal,finally the porous tungsten matrix was achieved.The results showed that:compared with raw tungsten powder without classifying,the particle size distribution of classified tungsten powder was narrower,and the tap density increased obviously,which indicated that the classified tungsten powder has better particle stacking performance.With the increase of sintering temperature,the porosity of rod billets made by classified tungsten powder decreased linearly from 22.8% at 1900℃to 17.8% at 2050℃.When the sintering temperature was 2000℃,the tensile strength of copper infiltrated tungsten could be 864 MPa,and after copper removal,the open porosity measured by MIP(mercury intrusion porosimeter)could be 19.85% and its average pore diameter was 1.39μm.The experiment indicated that the tungsten rod could be applied to highly reliable diffusion barium tungsten cathode manufacturing.