Synthesis of A1_8B_4C_7 and Its Oxidation Properties in Air

摘要

A1_8B_4C_7 has been synthesized and itsoxidation properties have been evaluated in both powderand sintered state. A1_8B_4C_7 can be synthesized atabove 1250 deg C by using Al + B_4C + C as a startingmaterial mixture. At 1800 deg C, no other phase couldbe identified. The process is achieved via gas phase.In the temperature range 700-1OOO deg C, the resultsshow that oxidation occurred by a parabolic kineticprocess, the activation energy of the process is 25.8kJ/mol, indicating that A1_8B_4C_7 powder is liable tooxidation. A sintered pure A1_8B_4C_7 body cannot besatisfactorily used in air at temperatures higher than1200 deg C because of its low oxidation resistance.