Novel low-temperature processing route of dense mullite ceramics by reaction sintering of amorphous SiO2-coated gamma-Al2O3 particle nanocomposites

Dense mullite ceramics were successfully produced at temperatures below 130 0 degrees C from amorphous SiO2-coated gamma-Al2O3 particle nanocomposites (AS-gamma A). This method reduces processing temperatures by approximate to 300 degrees C or more with respect to amorphous SiO2-coated alpha-Al2O3 pa rticle microcomposites (AS-alpha A) and to other Al2O3-SiO2 reaction couple s. The good densification behavior and the relatively low mullite formation temperature make AS-gamma A nanocomposites an excellent matrix raw materia l for polycrystalline aluminosilicate fiber-reinforced mullite composites.