Solution combustion synthesis of α-cordierite

The preparation of alpha-cordierite powders via combustion route was investigated. Urea, monoethanolamine and triethylenetetramine were used as fuels. The resulting powders were characterized by means of thermal analysis and XRD. Experimental results showed that SiO2 behaves as an inert material, preventing the formation of 2MgO center dot 2Al(2)O(3)center dot 5SiO(2) directly from the combustion reaction. Using a fuel mixture of urea and monoethanolamine yielded a poorly crystalline powder (MgAl2O4). The phase composition of powders after annealing at various temperatures has shown that the formation of alpha-cordierite occurs indirectly, via the solid state reaction of spinel and cristobalite. After annealing at 1300 degrees C for 1 h alpha-cordierite is virtually the only crystalline phase in the sample obtained with triethylenetetramine. In the sample prepared by using urea and monoethanolamine fuel mixture alpha-cordierite is the main crystalline phase, alongside traces of spinel and cristobalite. The intermediate formation of mu-cordierite was not observed. (C) 2009 Elsevier B.V. All rights reserved.