Ir—Ce合金阴极及其应用研究

重点研究了粉末冶金法制备Ｉｒ－Ｃｅ（铱－铈）合金阴极过程中压制压力和烧结温度对发射性能的影响，建立起了一套稳定的制备工艺。试验得到Ｉｒ－Ｃｅ掺Ｗ阴极在１７５３Ｋ时的发射电流密度达１２．４Ａ／ｃｍ２，电流密度保持为１．７Ａ／ｃｍ２，发射试验稳定达１５０ｈ。从机理上验证了它是一种高温大发射电流的发射体。试验还表明Ｉｒ－Ｃｅ阴极具有良好的抗中毒能力。作为应用研究，测量了该阴极在热阴极微波电子枪中的发射性能，微波腔场强约１０ＭＶ／ｍ，工作温度１９１３Ｋ，零场发射电流密度为１０Ａ／ｃｍ２，最大发射电流密度达２１Ａ／ｃｍ２，在２０２０Ｋ时计算零场发射电流密度可达４２Ａ／ｃｍ２。

THE IRIDIUM CERIUM ALLOY CATHODE AND ITS APPLICATION

The research is focused on the influence of pressing pressure and sintering temperature on the emission properties of Ir Ce alloy cathode made with powder metallurgy fabrication. A technique is developed to fabricate the alloy cathode.The emission current density of the cathode can reach 12.4 A/cm 2.However,only a current density of 1.7 A/cm 2 can sustain a stable measurement for 150 hours.The relationship between emission current and heating temperature of the cathode shows that the cathode is poisoning resistant and has good emission capacity at high heating temperature,which means that when the cathode temperature T is above 1773 K,the work function value decreases with increasing temperature.It is noted that maximum emission current can reach 21 A/cm 2 in the FR gun and the zero field emission current density J 0= 10 A/cm 2 . The calculation shows that J 0 can reach 42 A/cm 2 at T =2020 K.Finally,the application of Ir Ce alloy cathode is discussed.