Performance of Molybdenum-Based Silicides in Combustion and Endothermic Heat Treating Environments

摘要

Radiant tubes are used in heat treatingprocesses to isolate the combustion products from thefurnace atmosphere. Many radiant tubes currently inuse are made out of metals (nickel-chromium-based) ormullite. The major disadvantages of these materialsare their high cost and/or inferior thermomechanicalproperties. This article reports the findings of astudy conducted to determine the performance ofplasma-sprayed MoSi_2 and Mo_5Si_3, hot-pressedMoSi_2, and MoSi_2 composites containing SiC andSi_3N_4 reinforcements exposed to combustion andendothermic environments at 1025 deg C (2057 deg F)for 340 hours. Statistical strength analysis, coupledwith optical and scanning electron microscopy,indicated that the MoSi_2 composites reinforced withSiC and Si_3N_4 provide adequate strength and hightemperature oxidation and corrosion resistance to beconsidered as potential candidate materials for suchheat treatment furnace applications.