Tungsten electrode material and the effect of rare-earth metallic oxides on it

The development and research status of tungsten electrode materials are introduced. The requirements of electrode materials are analyzed in terms of the characteristics of the welding tip. A comparative study is made between W-ThO2 and pure tungsten electrode materials. In particular, the influence of rare-earth metallic oxides adding to tungsten electrode materials as replacements for ThO2 addition are discussed. The studies show that tungsten electrodes activated with 2wt% of rare earth metallic oxides have good form ability. The operating characteristics of electrodes depend strongly on the rare-earth oxide additions; their presence affects the operating, electrode temperature, work function, and the are stability. The equilibrium between the supply and diffusion due to surface evaporation of rare-earth metallic oxides is essential to are stability, electrode lifetime. The rare-earth metallic oxides Form tungstate or oxy-tungstate during are burning. These newly formed relatively low melting point compounds melt, migrate, as well as evaporate, during are burning. Rare-earth metallic oxides with various components and ratios in the tungsten electrodes have different effects on this migration and evaporation of the tungstate and oxy-tungstate compounds. At the same time, they affect the crystal structure upon recrystallization. All of the above factors combine to influence are burning, electrode consumption, and are stability. Among the tungsten electrodes activated with two or three types of rare-earth metal oxides(CeO2, La2O3 and Y2O3), the electrodes with the ratio of CeO2: La2O3: Y2O3 = 1: 1: 3 show the lowest electrode temperature and the best thermal emission, and have the best properties in terms of are starting and electrode consumption.