In situ synthesis of AlN whiskers in mullite-silicon carbide refractory under simulated coke dry quenching conditions

AlN whiskers in mullite-silicon carbide refractories were synthesized under the simulated conditions of service temperature and nitrogen flow in a coke dry quenching (CDQ) furnace. Nanoscale Fe powder and Si3N4-Fe powder were added as catalysts to the raw materials of the mullite-silicon carbide refractory containing metallic Al powder. The correlation between the microstructures and the sample properties were studied; the results showed that the formation and interaction of AlN whiskers in situ in the matrix improved the strength, thermal shock resistance, and toughness of the refractory. Nanoscale Fe powder was more effective as a catalyst for the formation and growth of AlN whiskers. The formation temperature of AlN whiskers in the samples containing nanoscale Fe powder was successfully decreased from 1000 to 850 °C under nitrogen flow.