Influence of heating temperature, keeping time and raw materials grain size on Al4O4C synthesis in carbothermal reduction process and oxidation of Al4O4C

Abstract

Several factors, influencing synthesis of Al4O4C in carbothermal reduction process from Al2O3 and C starting raw materials in argon atmosphere, and oxidation characteristics of Al 4O4C were investigated. The formed Al4O 4C in heated specimens was increased and Al2O3 and C were decreased with increase of heating temperature and extension of keeping time. Grain size of Al2O3 had obvious influence on synthesis of Al4O4C and fine Al2O3 was more advantageous. The activation energy of the reduction reaction from Al2O3 and graphite to form Al4O4C was calculated as 358.0 kJ/mol basing on experimental data. Al4O 4C was observed to be oxidized from about 820°C in air. Al 4O4C, buried in graphite powder and heated in air, was converted into Al2O3 and C.