PROCESS OF MANUFACTURE OF CATHODE HEATER Russian patent published in 2000 - IPC

FIELD: manufacture of cathode heaters. SUBSTANCE: process of manufacture of cathode heater includes vacuum prefiring of spiral at temperature (0,5-0,6)t_m in vacuum not worse than 13.3x10^-4 Pa in the course of 10-30 min followed by cooling with rate of 0.5-3.0 C/s to 800-900 C, coiling of spiral on holders with diametrical interference fit and fixing of spiral on holder at least in one point by electron-beam welding by way of melting of fusible material which melting temperature is below that of material of spiral. Wolframium-rhenium spiral is manufactured with ratio of diameter of wire to diameter of coiling not more than 1:8. Spiral guiding groove with depth of 0.6-0.9 diameter of wire is formed over length of 1.0-1.5 pitch of spiral in zone of spiral fixing on holder. Vacuum prefiring of spiral is conducted in threaded mandrel of heat-resistant ceramic with thread pitch equal to pitch of spiral of heater. Aquadag grease is removed from surface of wire in the course of 10-40 s prior to vacuum prefiring of spiral. EFFECT: improved quality and prolonged service life of cathode heater under conditions of hard thermal heat-up and thermal cycling in process of operation. 4 cl, 4 dwg