Cordierite ceramic through glass and ceramic routes from kaolin and talc

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 °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 °C and 1200 °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 × 10 -. °C -1 (in the range ~ 24 -500 and 700 °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.

Quasi‐synchronous solid‐state reaction for cordierite powder synthesis

“…The popular process used is a solid-state reaction in which a mixture of magnesiumaluminum-silica mineral powders containing silicates or oxides is calcined. In addition, in the literature, many processes, such as the sol-gel method, 6,7 glass crystal-lization method, 8,9 and mechanochemical method, 10,11 are reported.…”

Electrical, Microstructural and Physical Characteristics of Talc-based Cordierite Ceramics

“…The solid-state reaction is the applied method for preparing cordierite ceramics, according to the stoichiometric composition of cordierite, at high temperature using natural starting materials including MgO, Al 2 O 3 and SiO 2 [20,27,28]. The natural raw materials as talc, kaolin and feldspars are usually used in industrial/traditional production of cordierite ceramics because the chemical contents of these materials, in terms of SiO 2 , Al 2 O 3 , and MgO, are close to those of cordierite composition [27,[29][30][31].…”

Electrical, Microstructural and Physical characteristics of talc-based cordierite ceramics

“…The solid-state reaction is the applied method for preparing cordierite ceramics, according to the stoichiometric composition of cordierite, at high temperature using natural starting materials including MgO, Al 2 O 3 and SiO 2 [20,27, 28]. The natural raw materials as talc, kaolin and feldspars are usually used in industrial/traditional production of cordierite ceramics because the chemical contents of these materials, in terms of SiO 2 , Al 2 O 3 , and MgO, are close to those of cordierite composition [27,[29][30][31].…”

“…The solid-state reaction is the applied method for preparing cordierite ceramics, according to the stoichiometric composition of cordierite, at high temperature using natural starting materials including MgO, Al 2 O 3 and SiO 2 [20,27, 28]. The natural raw materials as talc, kaolin and feldspars are usually used in industrial/traditional production of cordierite ceramics because the chemical contents of these materials, in terms of SiO 2 , Al 2 O 3 , and MgO, are close to those of cordierite composition [27,[29][30][31].The talc-kaolin batches have been chosen as starting materials in the preparation of cordierite, which mentioned to the narrow ring range, usually with 50ºC [30]. Di culties in preparing cordierite are over-sintering and sintering without uxing agents [30,32,33].…”