| 摘要 |
<p>A sintering type cathode (C1) has a shell-shaped cathode tip end portion (35) consisting of a conical peak portion (31) provided on one edge side facing an anode and a cylindrical base portion (33) provided on the other edge side. The cathode tip end portion (35) forms an electron radiation portion for emitting electrons. The cathode tip end portion (35) contains a particle-form high-melting-point metal (41), an aluminum layer (43) covering at least part of the surface of the high-melting-point metal (41), and a metal oxide (45) as an easily electron-emitting substance. This cathode tip end portion (35) is formed by mixing into the aluminum layer (43)-coated metal (41) a compound (metal carbonate) containing a metal serving as easily electron-emitting substance and changed into a metal oxide (45) on heat treating, and sintering the mixture.</p> |
