The influence of attrition milling on the thermal decomposition of kyanite (Al 2O 3·SiO 2) to mullite (3Al 2O 3·2SiO 2) and SiO 2, and its subsequent sintering, was studied. A commercial kyanite was attrition-milled for times up to 12 h. Dilatometry confirmed that as-received unmilled kyanite decomposes between 1300° and 1435°C. The decomposition reaction is slow initially and accelerates during the later stages until about one-half of the decomposition occurs in the last 35°C. For the attrition-milled kyanite, the onset decomposition temperature decreases, the transformation temperature interval is reduced, and both the decomposition reaction and subsequent sintering are accelerated. A dense microstructure of fine equiaxed mullite grains in the 1 μm size range, evenly dispersed in a glassy matrix, is obtained by sintering the attrition-milled kyanites. These results are explained in terms of the energy accumulated during attrition milling, a reduction of the milled kyanite particle size, and the presence of a liquid phase during sintering.
|Original language||American English|
|Number of pages||2181|
|Journal||Journal of the American Ceramic Society|
|State||Published - 1 Oct 2002|
Aguilar-Santillán, J., Cuenca-Alvarez, R., Balmori-Ramírez, H., & Bradt, R. C. (2002). Mechanical activation of the decomposition and sintering of kyanite. Journal of the American Ceramic Society, 2425-2431. https://doi.org/10.1111/j.1151-2916.2002.tb00475.x