Reaction rates of refractory metal oxidation in cold oxygen plasma

The enhancement of oxidation of some metals in the presence of plasma was studied. To test the heat-resistant and corrosion-resistant materials, molybdenum, zirconium and titanium were selected as the evaluation material. The weight change of specimens resulting from the reaction with oxygen was measured by electro-microbalance in the temperature range 300–600 °C at the oxygen pressure of 5 Pa. Each specimen was found to be oxidized and changes its weight according to the definite oxidation law. The activation energy for oxidation was evaluated. Oxidation by plasma was confirmed to be accelerated far faster than thermal oxidation in the low temperature region.