DIRECTLY HEATED CATHODE OF ELECTRON TUBE AND ITS MANUFACTURE

摘要

PURPOSE:To improve the mechanical strength, emission characteristics, and life by forming a coating layer of a specific material on a core wire of tungsten. CONSTITUTION:Coating layer 5 of sodium carbide or a tungsten carbide-thorium alloy is formed on the surface of a tungsten core wire 4. Thus, the mechanical strength and life of this core wire are improved because required tungsten carbide is limited to a least amount and a sufficient amount of thorium atoms is distributed near the surface.