Abstract
Based on kaolin and talc, cordierite was prepared through melt quench and ceramic process of two compositions. The sintering process of ceramics between 1000 and 1300 degrees C shows mainly the manifestation of cordierite with little ratios of spinel, enstatite, mullite and cristobalite. However, the sintering of their corresponding glasses between 1100 degrees C and 1200 degrees C shows the crystallization of cordierite as the main phase with little cristobalite and spinel. In microstructure, the sintering of the ceramic samples revealed nano size rounded- or rod-crystals either free or in clusters in glassy matrix. Whereas, sintering of the corresponding glasses showed clear euhedral to subhedral tetragonal to hexagonal crystals in submicron scale that spread in the residual glassy matrix. The density of the sintered ceramic samples was in the range of 1.96 and 2.43 g/cm(3) corresponding to porosity of 29.34 and 5.46 % respectively. While the density of the sintered glasses was 1.90 and 2.35 gm/cm(3), corresponding to porosity of 36.20 and 3.30 % respectively. The sintered glass samples presented low and negative coefficient of thermal expansion (CTE) of 36.1 and -36.1 x 10(-6) degrees C-1 (in the range similar to 24 -500 and 700 degrees C). The microhardness values were between 468 and 577 Kg/mm(2). As a result, the prepared cordierite ceramic may be possibly used as refractoriness in electric heater supports, such as electric stove or heater cooling plate and ceramic heater base.