Cold cathode for a gas discharge tube with a layer containing alkali earth metals on a metallic support

摘要

The electrode (1) in its entirety forming a cold cathode for a gas discharge tube (2), includes a substrate (support) (3) made of ferrous sheet metal, covered with an active layer (4) on its internal face (3a). The substrate (3) is inserted into a tubular ceramic sheath (5), which extends beyond this substrate on the discharge side. The active layer (4) consists of stoved alkaline-earth metal (barium and/or calcium) titanate containing a reducing element such as silicon, zirconium and aluminium in a ratio of 10-6 to 10-8 moles of reducing element per mole of titanate. During stoving of the layer (4) at a temperature of between 750@ and 1000@C, it is assumed that the reduction products of the titanate form dopants for lowering and regulating the output potential. IMAGE