An anti-oxidation coating for W Mo and ZrO2 composite in a wide range from room temperature to 1200 °C

W Mo and ZrO ₂ composite has been used for molten steel temperature sensor. The sensor has an additional potential to measure the baking temperature of tundish. However, its oxidation during the baking (room temperature ~ 1200 °C) restricts this potential. Thus, an anti-oxidation coating has been developed. Raw materials of 20 wt% borax, 20 wt% potash feldspar and 60 wt% fused silica that had suitable melting temperature and low volatility were obtained and fused at 1200 °C to prepare borosilicate glass. Then, the glass powders were brushed on sensor surface through the slurry method, which was fused at 1200 °C to form the coating. The coating exhibited low volatility (weight loss: <0.5%), good compactness, continuity and adhesion to the matrix. Whether it was in solid or molten state (1000 °C or 1200 °C), it showed excellent oxidation resistance. Based on application test, it protected the sensor against oxidation during the baking. As a result, the sensor could be used to measure the baking temperature.