首页|钨粉颗粒形状对钡钨阴极发射性能的影响

钨粉颗粒形状对钡钨阴极发射性能的影响

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实验以两种不同颗粒形状的钨粉为原料,采用金属注射成形(MIM)技术制备了钡钨阴极用多孔钨基体,重点研究了粉末颗粒形状对多孔钨基体孔隙特征以及阴极发射性能的影响.结果表明:SW和NPW两种钨粉末粒度分布基本相同,但颗粒形状不规则NPW粉末具有较高的"赘生物指数"和凹度值,致使其比表面积更大.采用两种钨粉末制备的多孔钨基体的孔隙比容积几乎相同,相较于PNPW基体,使用颗粒形状规则的SW粉末制备的PSW基体开孔率更高、平均孔径更大;但PNPW基体内部形状不规则的钨粉颗粒与烧结颈形成的弯曲孔隙通道具有更高的孔隙比表面积,钨浸渍体内活性钡盐与钨粉颗粒的接触面积更高,相同时间内被还原出来的钡更多,使得阴极发射表面活性钡原子的覆盖率更高,降低了阴极功函数,进而提高了阴极的发射电流密度.
Effect of tungsten powder particle shape on the emission properties of the barium-tungsten cathode
Porous W matrixes for dispenser Ba-W cathodes were prepared by metal injection molding(MIM)us-ing W powders with different particle shapes as raw materials.The influence of the powder particle shape on the pore characteristics of porous W matrix and the emission properties of the Ba-W cathode was studied.The results show that although the particle size distribution of spherical W powders(SW)and narrow particle size distribution W powders(NPW)powders are basically the same,the NPW powders have a higher specific surface area than SW powders for the higher"Outgrow"and Concavity value.The pore-specific volume of porous W matrix prepared by two different powders is almost the same,compared with the PNPW matrix,the Psw matrix has higher open porosity and larger average pore size.However,the sinuous pore channels formed by the irregularly shaped W powder parti-cles and sintered necks inside the PNPW matrix have a higher pore-specific surface area,which results a higher con-tact area between the impregnants and the W powder particles.Therefore,more barium atoms are reduced in the same time,which make the coverage of the active barium atoms on the cathode emission surface higher,reduces the cathode work function,and the emission current density of the cathode is improved.

dispenser cathodemetal injection moldingpowder shapeporous tungsten matrixemission property

王明辉、胡可、杨世松、吴仁君、张方阳、林波

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贵州大学机械工程学院,贵州贵阳 550025

广东省科学院新材料研究所,钛及稀有金属粉末冶金国家工程研究中心,广东广州 510650

惠州城市职业技术学院智能制造学院,广东惠州 516025

扩散式阴极 注射成形 粉末形状 多孔钨基体 发射性能

广东省自然科学基金资助项目广东省科学院建设国内一流研究机构行动专项资金项目广东省科学院建设国内一流研究机构行动专项资金项目广东省科学院建设国内一流研究机构行动专项资金项目河源市省科院研究院研究专项

2021A15150104702021GDASYL-202103020082022GDASZH-20220101092022GDASZH-20220102012021GDASHY-0107

2024

10.13228/j.boyuan.issn1006-6543.20230033

粉末冶金工业
中国钢研科技集团有限公司 中国钢协粉末冶金分会 中国机协粉末冶金分会

粉末冶金工业

CSTPCD北大核心
影响因子：0.406
ISSN：1006-6543
年,卷(期)：2024.34(2)
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