Effects of transition metals on the oxidation behavior of ZrB2 ceramics

• Oxidation behavior was studied for ZrB2 and ZrB2 with 4 mol% W, Mo, or Nb 1600 °C.
• Initially, the surface of the ZrB2 specimens were covered by a glassy layer.
• (Zr,Mo)B2 and (Zr,Nb)B2 had more stable glassy layers.
• Oxide scales consisted of inner and outer layers.
• Addition of W, Mo, or Nb resulted in thinner inner layers and thicker outer layers.

The effects of transition metal additives on the oxidation behavior of ZrB2 ceramics at 1600 °C were investigated. Additions of W, Mo, or Nb improved the oxidation resistance of ZrB2 even after evaporation of the protective B2O3 layer. The oxide layers were composed of an outer layer that was porous and had light color and an inner layer that was dense and appeared dark. Additions of Mo or Nb were more effective than W at improving the oxidation resistance of ZrB2 at 1600 °C due to a lower evaporation rate for B2O3 glasses containing Nb and Mo compared to W.