| 摘要 |
<p>PURPOSE:To suppress the heater power and to improve the thermal efficiency by forming the outer side of a sleeve with a high melting point metal, the inner side with a nickel-chromium type alloy, and covering the inner surface with a chromium oxide. CONSTITUTION:In a cathode sleeve 2, the outer side is formed of a high melting point metal, the inner side is formed of a nickel-chromium type alloy, and the inner surface is covered with a chromium oxide. The high melting point metal may be a unit metal or an alloy of molybdenum, tantalum, niobium, or the like, and the nickel-chromium alloy is the nickel including 1 to 30wt.% of chromium. The outer side high melting point metal has a large high- temperature strength, and can prevent the sleeve deformation in the service life of an impregnated type cathode. And the inner side nickel-chromium type alloy can absorb the radiant heat from a heater 1 effectively by forming a selective blackening membrane on the surface.</p> |
