Abstract:
A dark heater is produced by a method which comprises coating the first coating layer made of an insulating material with a suspension containing heat-resistant particles having a high thermal emissivity, such as W particles, while 0.5 to 1.5 wt. % of a volatile matter such as water remains in the first coating layer to form a dark coating layer. Since the suspension having a low viscosity can be used, the thickness of the dark coating layer can be made highly uniform and the emission characteristics of the heater can be stabilized.
Abstract:
A method of manufacturing a heater comprises: (a) washing alumina particles with warm running-water of at least 40° C.; (b) preparing a suspension for electrodeposition by suspending the washed alumina particles in a predetermined liquid; and (c) forming an alumina insulating layer made of the alumina particles on a metal wire as a heater base metal provided inside a cathode of an electron gun by electrophoresis using the suspension for electrodeposition.
Abstract:
A method of producing an aluminum oxide and tungstate powder for insulating cathode heaters includes mixing a finely divided aluminum oxide powder with ammonium tungstate, rinsing out excess ammonium tungstate, drying the mixture and heating in a nitrogen-hydrogen atmosphere to about 700.degree.C.