MECHANICAL, PHYSICAL AND THERMO-MECHANICAL PROPERTIES OF AL_2O_3-C REFRACTORIES UNDER OXIDIZING ATMOSPHERES

摘要

The Al_2O_3-C refractory articles are widely used as monobloc stoppers in steel applications. Due to their poor oxidation resistance, these articles are coated with a protective glaze to inhibit carbon oxidation. An innovative improvement is the development of such glaze free refractories. An investigation of the mechanical, physical and thermo-mechanical properties of Al_2O_3-C refractories under oxidizing atmospheres was carried out at the present work. The composition and the structure of these refractories were modified with the addition of metallic antioxidants and other oxides. The physical and mechanical properties were determined after oxidation tests in air. As for the thermo-mechanical properties of the Al_2O_3-C refractories, these were determined with hot modulus of rupture and thermal shock experiments. It was shown that the adhesion of the burnt out layer of the samples should be improved. The bonding between burnt out layer and non-oxidized sample needs to be reinforced. The addition of silicon proved to be favourable in comparison with aluminium addition.