Effects of temperature and the incorporation of W on the oxidation of ZrB2 ceramics

• The oxidation behavior of ZrB2 with 0, 4, 6, or 8 mol% W was studied at 800–1600 °C.
• The stability of the glassy layers were higher for (Zr,W)B2 specimens.
• The (Zr,W)B2 compositions had thinner oxidation scales compared to ZrB2 at 1600 °C.
• The addition of W into B2O3 increased the stability of the protective glassy layer.
• More stable glassy layer resulted in higher oxidation resistance for (Zr,W)B2.

The effects of tungsten additions and temperature on the oxidation behavior of nominally pure ZrB2 and ZrB2 containing 4, 6 or 8 mol% of W after oxidation at temperatures ranging from 800 to 1600 °C were investigated. For pure ZrB2, the protective liquid/glassy layer covering the surface as a result of oxidation was evaporated above 1500 °C. For (Zr,W)B2 specimens, the liquid/glassy layer was present after exposure up to 1600 °C. The higher stability of the liquid/glassy phase in the W-containing compositions was attributed to the presence of tungsten in the liquid/glassy phase, resulting in improved oxidation resistance for ZrB2 samples containing W.