| 摘要 |
PROBLEM TO BE SOLVED: To provide a stable electron emitting characteristic by reducing containing carbon element component and oxygen component by providing a process of temporarily sintering in a hydrogen atmosphere containing steam and a process of regularly sintering in a hydrogen atmosphere or a vacuum. SOLUTION: For example, a mixture such as barium oxide is impregnated into the respective pores as an electron emitting substance 1a by using a sintered conductive porous body (a porous sintered body 11) of an integral structure composed of tungsten having constant porosity. In forming this porous sintered body 11, first of all, tungsten powder, an organic binder and water are mixed to form slurry to be formed as a mold after being granulated. In a temporarily sintering process, the mold is temporarily sintered in a hydrogen atmosphere of one atmospheric pressure being 30% in the ratio of water vapor pressure under a condition of 1000 deg.C and for one hour. In this case, a temperature range is set to 600 deg.C to 1500 deg.C. Next, the mold is regularly sintered in a vacuum of about 10-4 Torr under a condition of 1800 deg.C and for three hours. In this case, the temperature range is set to 1500 to 2000 deg.C.
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