Influence of nano alumina addition on the properties of SiC refractories

The refractory industry is highly matured and to counteract the fierce competition from the foreign markets, the only way is to develop new technologies that have high added value and cannot be easily copied. Silicon carbide refractories have wide range of applications because of its unique properties. Nanotechnology has brought about a revolution in the refractories field by exhibiting remarkable performance. The objective of the present work is to study the influence of incorporation of nano alumina powder to the matrix part of silicon carbide refractories. Nano alumina was synthesised by sol-gel technique and characterised by various analytical techniques. Apparent porosity, bulk density, cold crushing strength, cold and hot modulus of rupture, modulus of elasticity as well as fracture surface analysis through SEM have been evaluated for the SiC bricks added with nano alumina powder (0-0.5 wt %). The obtained results show an improved densification and better sintering upon addition of nano alumina powder due to enhanced compaction by filling up the interior voids and pores between various SiC particles. Nano alumina added SiC bricks show high hot strength, high erosion and abrasion resistance and excellent thermal shock resistance at elevated temperatures. They have potential applications in kiln furniture.