New Thermionic Cathodes Coated with Ba-Ta-Zr-O-N System Produced by Carbothermal Reduction and NitridationProcess

摘要

Ba(Ta1-xZrx)OεNδ compounds for x = 0～1 were produced by carbothermal reduction and nitridation process. In this process, Ba(Ta1-xZrx)OεNδ and TaC as a second phase were observed by X-ray powder diffractionpatterns. Work functions and barium vaporization temperatures of the obtained powders were estimated. Work functions of the Ba(Ta1-xZrx)OεNδ compounds increased with increasing zirconium content, and the value of 1.7eV for x = 0.1 was less than that of 2eV with alkaline earth oxide. Barium in the Ba(Ta1-xZrx)OεNδ compound was volatileat higher temperature than that of authentic hot cathodes coated with alkalineearth oxide. In the 4.1mm of outside diameter, 3.3mm of inside diameter, and 100mm length of glasses with 9.3kPa of argon gas and mercury, some fluorescentlamps with hot cathodes coated with Ba(Ta0.8Zr0.2)O0.2N0.6 compound worked excellently and those has been litfor 61.2Ms, so far.