Effect of bonding phases on the properties of Al2O3 based slide gate plates

Abstract

In the present work different quality of alumina are taken along with different metals as the starting materials. Different compositions are formulated taking single or combination of metals which are mixed with phenol formaldehyde resin and pressed with a specific pressure of 2000kg/cm2. The bricks are cured at 240°C for 12 hours. Physical, thermal and thermo mechanical properties are evaluated. Also the bricks are fired at 1100°C in reducing atmosphere. Physical, thermal and thermo mechanical properties are evaluated and correlated with the mineralogical and microstructural analysis. Based on these findings carbon bearing plates are made with the addition of carbon black or carbon black and graphite. The addition is restricted up to 5%. Properties are evaluated and correlated with mineralogical and microstructural analysis. Plates containing aluminium metal shows superior thermal and thermo-mechanical properties than silicon metal containing Al2O3 slide plates. However plate containing metal in combination has the best thermal and thermo-mechanical properties. Fused alumina based plates has comparatively superior properties for all grade of metal addition. Plate containing both carbon black and graphite flake was having comparatively efficient properties in carbon bonded slide plates. To improve the thermal shock resistance, corrosion resistance and oxidation resistance, along with mechanical properties, in situ synthesised plasma fused ZrO2-SiC was incorporated in the Al2O3 –C slide gate plates. Apart from mechanical properties, thermal spalling resistance, erosion resistance and oxidation resistance of these slide plates were compared with the normal ones. The metal bonded slide gate plates are fired in 1600°C in nitrogen atmosphere for forming nitride bonds. These nitride bonded slide plates were giving significant enhancement in properties and it can be a suitable substitution for all the carbon bonded slide gate plates.