Thermal and Microstructure Stability of Cordierite–Mullite Ceramics Prepared from Natural Raw Materials-Part II

Sintering and final properties of kaolinite‐magnesite tapes for the manufacture of cordierite‐mullite ceramics

“…In addition, at higher sintering temperature (1200°C), the porosity (see Figure 4) of samples decreased (40% and 49% for 0 and 3 mass% of magnesite, respectively) and thermal conductivity of the two samples without and with 3 mass% of magnesite increased, 0.84 and 0.86 W.m −1 .K −1 , respectively. These observations appeared to be in good agreement with previous works of Albhilil et al 3,8 After firing at 1200°C (soaking time 30 minutes), the sample with 3 mass% of magnesite presented the highest apparent porosity content while no cordierite was detected. Indeed, the decomposition of kaolinite and of magnesite during heating contributed to increase porosity content, and since the amount of magnesium did not promote the occurrence of cordierite under this firing conditions, only mullite was formed arising from metakaolinite structural reorganization.…”

“…Consequently, the sole occurrence of mullite was not enough to balance the lack of cohesion within the studied samples since the temperature was not appropriate to enhance the contribution of magnesium to lower the viscosity of amorphous phases (promotion of viscous flow sintering) and/ or to react with silica and alumina to form cordierite. The ternary phase diagram MgO‐Al 2 O 3 ‐SiO 2 (MAS), β‐cordierite could be expected in the temperature range 3,5,9‐11 1000°C to 1100°C, but we could not afford to reach ideal homogeneity within our mixture (powder with liquid route mixing) and thermodynamic equilibrium during our firing conditions. Therefore, this could justify the delay observed for the crystallization of cordierite (1200°C) in our samples, and thus related to the diffusion of magnesium.…”

“…The ternary oxide system MgO‐Al 2 O 3 ‐SiO 2 (MAS) is characterized by two main minerals: cordierite (2MgO.2Al 2 O 3 .5SiO 2 ) and mullite (3Al 2 O 3 .2SiO 2 ), which have been the subject of several studies 1‐5 . However, in the MAS system, cordierite‐mullite composites attract much attention due to its: (i) high chemical and thermal stability; (ii) low expansion coefficient, conductivity, and dielectric constant; and (iii) excellent mechanical resistance at high temperature 4,6,7 .…”

Preparation and performance study of cordierite/mullite composite ceramics for solar thermal energy storage

“…14 Therefore, both of them are dependable and durable for thermal heat storage applications. 15,16 The focus of this study is to produce cordierite-mullite composite ceramic used as honeycombed sensible thermal storage materials in solar thermal energy storage system, with PCM (K 2 SO 4 was designated in this study as PCM) filled in the porous channel, as given in Figure 1. And such a study on the preparation of cordierite-mullite composite ceramic is needed because excellent thermal shock resistance and enhanced mechanical strength are desired in thermal energy storage materials.…”

Review on the elaboration and characterization of ceramics refractories based on magnesite and dolomite

“…The ceramic materials resulted after firing, were investigated regarding their phases composition and physical properties of technological interest. Albhilil et al [109] Thermal and microstructure stability of cordierite-mullite ceramics prepared from natural raw materials -Part II…”