Discharge tube or discharge lamp and scandate-dispenser cathode

摘要

An electrical discharge lamp, eg low pressure gas type, has a scandate dispenser cathode that is formed of a cathode body covered with an emitting surface. The cathode body is of a matrix formed from either a high melting point material or a high melting point alloy together with a barium binding material. Chemical reaction results in emission from the surface. A cover with one or more layers of tungsten and/or tungsten alloy, an intermediate layer of rhenium and a top coating of scandium oxide mixed with a rare earth metal oxide completes the structure