| 摘要 |
PURPOSE: An impregnation type cathode of a cathode ray tube is provided to increase productivity for the cathode by decreasing a sinter temperature and a sinter time of a high melting point metal and increase impregnation efficiency of electron emission material to stably emit electrons. CONSTITUTION: An impregnation type cathode of a cathode ray tube comprises a cathode pellet of a tungsten porous sintered body and an impregnated electron emission material. Surface of tungsten powder having an average grain size of 2 microns is coated with a dopant such as at least one of Pt, Ir, Pr and Ni by a thickness of 4-10MLs(1MN=1.5x10¬15atoms/cm¬2) by ion injecting or depositing. The coated tungsten powder is molded to be a porous body having a thickness of 0.4mm, a diameter less than 1.1mm and a porosity of 24-40% by pressing. The molded porous body is sintered at a relatively low temperature of 1400°C for a relatively shot time of 1 hour. When the coated tungsten is sintered, the dopant is diffused along the surface of the tungsten powder.
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