METHOD FOR PRODUCING EMISSIVE MATERIAL FOR OXIDE CATHODES Russian patent published in 2000 - IPC

FIELD: electronic engineering. SUBSTANCE: emissive material for oxide cathodes of vacuum tubes and gas-discharge devices based on composite compounds of alkali-earth metals (Ba, Sr, and Ca) is produced by using method that involves deposition of difficult-to-dissolve compounds of alkali-earth metals out of aqueous solutions of their nitrates with solution of ammonium oxalate and ammonium carbonate mixture having mole proportion (NH₄)₂C₂O₄:(NH₄)₂CO₃ = 0,3÷0,7:0,7÷0,3. Deposits obtained are separated from mother liquor by means of Buchner funnel, rinsed with distilled water, and dried out at 100-150 C for 10 h. As an alternative, they may be vacuum dried at temperature of 240-250 C and residual pressure of 5•10^-2 - 1•10^-2 tors. Material is designed to improve operating and other characteristics of vacuum tubes and gas-discharge devices using them. EFFECT: improved emissive capability and emissive uniformity of material. 1 tbl, 6 ex