Oxidation Behaviour and Rim Formation Mechanism of Tungsten Electrode(Physics, Process, Instrument & Measurement)

概要

論文の詳細を見る
The oxidation behaviour and vaporization of tungsten electrode activated with La_2O_3 (2%) during arcing was measured and compared in Ar+O_2 mixtures containing 0.2% oxygen and pure argon at 1 atm total pressure. The presence of oxygen in shielding gas enhances the vaporization rate of tungsten and forming rim. Theoretical studies were carried out to evaluate the oxidation and vaporization rates of tungsten. The rates generally decreases with increasing temperature, i.e. in the direction to the electrode tip. Investigation by SEM and direct observation of arc were carried out to observe the formation steps, structure and the location of rim The experimental results are in reasonable agreement with theoritical studies. The formation mechanism of rim was attributed to the vaporization, dessociation and deposition phenomenas of tungsten oxides which occured simultaneously along the electrode surface during arcing.
大阪大学の論文