The Dissociative Vaporization of Alkaline Earth-Containing Mixed Oxide Thermionic Emission Materials

Abstract

The high-temperature chemistry of some mixed oxide thermionic emission materials has been studied by Knudsen cell mass spectrometry. It has been shown that these materials, such as Ba₂CaWO₆ and Ba₃Y₂WO₉, vaporize by a dissociative process. The dominant volatile components over these materials are BaO(g), Ba(g), and Ca(g), with BaWO₄(g) and BaWO₃(g) being present in lower concentrations. The decomposition of these materials begins at approximately 1300°C.