金属掺杂钨基合金阴极的二次电子发射系数研究

Secondary electron emission coefficient of metal doping W-base alloy cathode

实验中制备了W-Re,W-Sc,W-Zr,W-Y合金阴极,其中Re,Sc,Zr,Y元素所占合金阴极材料的质量分数都为5%。二次电子发射系数测试结果显示,Re掺杂合金阴极对提高纯钨阴极二次电子发射能力显著,掺杂5%Re的W-Re合金阴极材料具有最大二次电子发射系数,其值为1.8,相比于纯钨阴极,能够提高80%。鉴于Re对提高纯钨阴极二次电子发射能力显著,对Re掺杂质量分数分别为20%,10%,6%,5%,4%,3%W-Re合金阴极材料二次电子发射系数进行了研究,发现随着Re在W-Re合金阴极材料中含量的降低,其二次电子发射系数在不断增大,仅当Re含量下降至5%左右时,合金阴极具有最大二次电子发射系数,继续下降至4%,合金阴极二次电子发射系数不但没有升高,相反下降至1.41,当下降至3%时,合金阴极二次电子发射系数值迅速降低为1.1。

W-Re, W Sc, W-Zr, W-Y metal alloy cathodes were prepared, with Re, Sc, Zr and Y in metal alloy cathodes having the same mass fraction of 5 ~. Secondary electron emission coefficient testing results show that Re doped metal alloy cath odes can enhance the coefficient of pure W cathode sintered with W powder in the same preparation environment remarkably. 20%, 10%,6 %, 5%, 4% and 3% mass fraction Re doped metal alloy cathodes were researched. 5% Re doped W Re metal alloy cathode has the biggest maximum secondary electron emission coefficient of 1.8, 80% higher than that of pure W cathode. With the mass fraction of Re reducing, the coefficient of metal alloy cathodes were rising. When the mass fraction of Re dropped to 5%, metal alloy cathode had the biggest coefficient. However, for the mass fraction 4% of Re, the maximum coefficient of the metal alloy cathode dropped to 1.41. For the mass fraction 3% of Re, the maximum coefficient of metal alloy cathodes was only