Development of alkali free glaze for refractory application application

Abstract

In the high temperature applications, mostly in the molten metal casting industries, the carbonaceous refractory bricks had been widely used due to its better thermal shock resistance and well appreciated mechanical properties. In most of the cases, the major problem had been faced due to the low oxidation resistance of the carbonaceous refractory bricks. In spite of the addition of the antioxidant, the level of oxidation had been the major problem faced by the Ceramic Engineers. In this scenario, an alkali free glaze composition had been developed, which can be applied as an antioxidant coating on the refractory bricks. Al2O3−SiO2−B2O3−MgO−CaO Glass system had been taken for the preparation of glaze. The glaze maturing temperatures had been determined by firing the glaze samples at 1350°C, 1450°C and 1500°C. Four glaze compositions had been prepared and applied on the zirconia-graphite refractory bricks. After glaze application, the bricks had been tested for oxidation. Brazilian disc test had been done for the glaze samples to determine the tensile strength. Rheological properties of the glaze compositions had been analyzed by using the Rheometer. Phase analysis of the oxidized and fired glaze samples had been done by powder X-ray diffraction method. Furthermore the FTIR analysis of the glass powder had been done for the identification of different bonds present. Vickers hardness of the annealed glass samples had been done.