IMPREGNATED TYPE CATHODE AND MANUFACTURING METHOD THE SAME

摘要

The impregnated cathode is produced by (a) sintering a tungsten powder under the reduction atmosphere at 1900-2300 deg.C to obtain a sintered body, (b) infiltrating an oxide of BaO, CaO and Al2O3 in the body to form a porous metal substance, (c) inserting the substance into the ring of a high m.p. metal material, (d) melt-spraying at least one of W, Mo and/or Ta beneath the substrate by the arc plasma spraying method to form a sealing layer, (e) horizontally inserting the sealing layer into the sleeve, (f) forming a coating layer on the substrate, and (g) fixing the heater to the inner of the sleeve. The cathode has an excellent electron emission effect of a high current density.