Novel Low‐Temperature Processing Route of Dense Mullite Ceramics by Reaction Sintering of Amorphous SiO 2 ‐Coated γ‐Al 2 O 3 Particle Nanocomposites

Dense mullite ceramics were successfully produced at temperatures below 1300°C from amorphous SiO 2 ‐coated gamma‐Al 2 O 3 particle nanocomposites (AS‐gammaA). This method reduces processing temperatures by similar/congruent300°C or more with respect to amorphous SiO 2 ‐coated alpha‐Al 2 O 3 particle microcomposites (AS‐alphaA) and to other Al 2 O 3 ‐SiO 2 reaction couples. The good densification behavior and the relatively low mullite formation temperature make AS‐gammaA nanocomposites an excellent matrix raw material for polycrystalline aluminosilicate fiber‐reinforced mullite composites.