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

The present work aims at studying the effect of the sintering temperature and magnesite addition on the structure and final properties of silicate ceramics tapes. A kaolinitic clay from Algeria was selected and mixed with different magnesite contents (≤12 mass%). Tape casting process was used to produce the green tapes in an aqueous system with optimized amount of surfactants. The green tapes were fired from 1000°C to 1200°C using a dwelling time of 30 minutes. The effect of the dwelling time was investigated for a firing temperature of 1200°C namely: 30 minutes, 1 hour 30 minutes and 3 hours for samples with 6 and 12 mass% of magnesite. Regarding firing conditions, crystalline phases, thermal conductivity, porosity, and flexural strength were analyzed. The results showed that increasing the sintering temperature to 1200°C tended to significantly decrease the total porosity of samples, which led to the improvement of the stress to rupture values. Specimens with 6 and 12 mass% sintered during 3 hours exhibited highest stress to rupture values (≈117 MPa) and lowest thermal conductivity (<0.2 W.m−1.K−1) and moderate open porosity (27%). The as‐obtained ceramics appeared promising for further utilization in refractory industry, thanks to the presence of both cordierite and mullite phases.

Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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

Hammas

Lecomte‐Nana

Daou

et al. 2020

“…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.…”

Section: Introductionmentioning

confidence: 99%

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

Zhang

et al. 2016

The employment of solar energy in recent years has reached a remarkable edge. It has become even more popular as the cost of fossil fuel continues to rise. Energy storage system improves an adjustability and marketability of solar thermal and allowing it to produce electricity in demand. This study attempted to prepare cordierite/mullite composite ceramics used as solar thermal storage material from calcined bauxite, talcum, soda feldspar, potassium feldspar, quartz, and mullite. The thermal physical performances were evaluated and characterized by XRD, SEM, EPMA, and EDS. It was found that the optimum sintering temperature was 1280°C for preparing, and the corresponding water adsorption was 11.25%, apparent porosity was 23.59%, bulk density was 2.10 mg·cm−3, bending strength was 88.52 MPa. The residual bending strength of specimen sintered at 1280°C after thermal shock of 30 times decreased to be 57 MPa that was 36% lower than that before. The thermal conductivity of samples sintered at 1280°C was tested to be 2.20 W·(m·K)−1 (26°C), and after wrapped a PCM (phase change materials) of K2SO4, the thermal storage density was 933 kJ·kg−1 with the temperature difference (ΔT) ranged in 0‐800°C. The prepared cordierite/mullite composite ceramic was proved to be a promising material for solar thermal energy storage.

“…Generally, increasing the crystallization temperature reduces the viscosity of the liquid phase, of which viscous flow is promoted, correspondingly increasing the densification of glass–ceramics 18 . Furthermore, increasing crystallization temperature enhances the transformation of µ cordierite to α cordierite 18 . Sample B0 crystallized at 900°C was characterized with a loose microstructure.…”

Section: Resultsmentioning

confidence: 99%

“…CTEs reveal a significant effect on the thermal shock resistance of ceramics 18 . The CTEs of samples B0‐B3 crystallized at 1000°C were investigated and shown in Figure 7.…”

Section: Resultsmentioning

confidence: 99%

Preparation and characterization of cordierite glass–ceramics for bonding solar thermal transmission pipelines

Ding

et al. 2021

TiO2 was employed to develop cordierite glass–ceramics for thermal transmission pipeline binders by a melt‐quenching method. The effects of TiO2 on the phase composition, microstructure, and physical properties of glass–ceramics were studied. In addition, the thermal shock resistance of the glass–ceramics based binder was investigated. The results showed the formation of α cordierite could be increased by adding 1.0 wt% TiO2, thereby improving bending strength and decreasing the coefficient of thermal expansion. However, a 3‐5 wt% TiO2 additive resulted in massive generation of µ cordierite, which exhibited a negative effect on the above performances. After crystallization at 1000°C for 2 h, sample B1 (1 wt% TiO2 additional) displayed the best overall properties. It was demonstrated that cordierite glass–ceramics were satisfactory materials as heat transmission pipeline binders when the C2 binder (40 wt% frit, 60 wt% as‐prepared sample B1) was applied, which had a good thermal shock resistance.