Effects of rhenium contents on oxidation behaviors of tungsten-rhenium alloys in the oxygen gas atmosphere at 873 K

Oxidation kinetics of pure tungsten (W) and tungsten-rhenium (W-Re) alloys with Re contents of 1%, 5% and 15% has been examined in the oxygen gas atmosphere at 873 K. The oxidation kinetics of the W-Re alloys were well characterized by a parabolic rate law. During oxidation of the W-Re alloys, the Re oxide sublimated near the top surface of the oxide layer. The sublimation of the Re oxide may play roles as a sintering agent and/or a stress relief agent in the W oxide layer to be more resistant to oxidation than pure W. There will be an effective value of Re content in W oxide layers for suppression of oxidation depending on oxidation temperatures or atmospheres. The Re oxide in the gas phase could deposit at cooler remote area on materials surface. Furthermore, the Re oxide deposits can be easily moved or transported to different area by dissolving in a water content or a moisture of flowing gas atmosphere.