Hot corrosion of SiO2-Ta2O5 binary scale on MoSi2-based ceramics

Abstract

The SiO2-Ta2O5 binary scales with different Ta2O5 contents were prepared on MoSi2-based ceramics by pre-oxidation. Hot corrosion with Na2SO4 was carried out at 1000 °C for 8 h. The pre-oxidized SiO2-Ta2O5 scale on ceramics with 10 % Ta2O5 has an excellent hot corrosion resistance. Ta2O5 reacted preferentially with Na2SO4 forming solid sodium tantalates to retard the dissolution of SiO2. A dense reaction layer can be formed to prevent the further infiltration of Na2SO4. Compared to the pure SiO2 scale without Ta2O5, fewer Na2MoO4 and no obvious corrosion hole can be observed.