Al ₂ O ₃ –ZrO ₂ –SiO ₂ Ternary Glasses for Molybdenum Oxidation Barriers

Abstract

The wettability of binary and ternary glasses belonging to SiO 2 –Al 2 O 3 –ZrO 2 diagram has been studied using the sessile drop technique at 1750° and 1800°C. The ternary SiO 2 –Al 2 O 3 –ZrO 2 (90–5–5 wt%) glass has proved to be well appropriated as a molybdenum oxidation barrier coating. The addition of 5 wt% of MoO 2 slightly improves its wettablity at higher temperatures without affecting its oxidation barrier properties. The Mo comes into the glass network as a mixture of Mo 5+ , Mo 4+ , and Mo 6+ . After oxidation at 1000°C in oxygen atmosphere, the molybdenum remains in the glass network as Mo 6+ .