In situ formation of sintered cordierite–mullite nano–micro composites by utilizing of waste silica fume

Fabrication and properties of cordierite–mullite bonded porous SiC ceramics

“…At 1350-1450 1C, the amount of Al 2 O 3 disappeared because of the better crystallization of cordierite. Previous studies [11,17] support the data obtained in this study, where the cordierite peak intensity at 1350-1400 1C was higher than that at 1300 1C.…”

“…However, the α-cordierite peaks decreased abruptly, and more extensive mullitization took place. It can be explained by the reaction of glassy phase produced form the dissociation of cordierite at 1450 1C [17].…”

“…Further, MgO affected both solid diffusion and crystallization processes by modifying the ion diffusion at high temperatures [25], and the diffusion rate of Al 3 þ ions in silicate glasses was much lower than that of Mg 2 þ ions [26]. The possible factors affecting the strength are as follows: (i) the development of a large amount of glass phase; (ii) cordierite formation and dissociation; and (iii) mullite crystal formation and growth [17].…”

Preparation and Characterization of Mullite-Alumina Structures Formed "In Situ" from Calcined Alumina and Different Grades of Synthetic Amorphous Silica

“…5a-e) are comprised of porous granular packs of individualized particles containing very low necking points. These two aspects indicate that only physical rearrangements, such as pore coalescence or viscous flow 8,32,49 , occurred up to 1100ºC and that the physical properties of the structures were defined mainly by the calcined alumina matrix behavior.…”

“…1d) particles are spherical, dense and individualized and their broad particle size distribution ranges from 50 to 500 nm. They are obtained as a precipitated by-product during the production of elemental silicon and are widely used in civil construction for enhancing the packing of high performance concrete, and in refractories for the production of mullitebased bricks and castables 1,7,8,15,38,39,48,49 . After physical characterization, the SAS particles were combined with calcined alumina to produce in situ mullite dense parts.…”