Oxidation behavior of pure W and W-0.5 wt% ZrC at 700 °C and 900 °C

Abstract

This study investigates the oxidative behavior of pure tungsten and a W-0.5 wt% ZrC alloy (WZC05), was examined. Both materials were fabricated via sintering and hot rolling. The alloys were exposed to air at 700 °C for 20 h and to air at 900 °C for 8 h to analyze surface morphology, oxidation resistance, and oxidation behavior of pure tungsten and WZC05. WZC05 exhibited a significantly smaller grain size than pure tungsten. At 700 °C, the “positive effect of grain size,” caused a higher oxidation rate in pure tungsten compared with that in WZC05. After air oxidation for 20 h at 700 °C, the thickness of the oxide layer on pure tungsten reached 320 μm, whereas that on WZC05 was only 202 μm. At 900 °C, the dense oxide layer was destroyed owing to the formation of volatile WO₃, resulting in similar oxidation rates for pure tungsten and WZC05. Scanning electron micrographs revealed that the oxidized tungsten materials had a layered structure.