Replacement of Flake Graphite in Alumina-carbon Refractories by Hexagonal Boron Nitride

摘要

Three kinds of composite alumina refractories were prepared with tabular alumina( 3- 1 and 1- 0 mm) as aggregates, tabular alumina powder, α-Al2O3 micropowder,and Si powder as matrix,adding 3 mass%hexagonal boron nitride( h-BN), 3 mass% flake graphite and 10 mass% flake graphite, respectively.Cold physical properties,hot modulus of rupture,oxidation resistance,thermal shock resistance and slag corrosion resistance of the specimens were compared. The results show that:( 1) physical properties and hot modulus of rupture of Al2O3- h-BN refractories are slightly different from those of low carbon Al2O3- C refractories,but better than those of traditional Al2O3- C refractories with 10 mass% graphite;( 2) Al2O3- h-BN refractories have better thermal shock resistance and oxidation resistance than the carbon containing refractories,while similar slag resistance with low carbon Al2O3- C refractories;( 3) h-BN can replace flake graphite as a starting material for the preparation of composite alumina refractories,considering the overall properties of the material.