Design and characterization of porous mullite based semi-vitrified ceramics

Deutou, N. J. G.; Béda, Tibi; Biesuz, Mattia; Boubakar, Likiby; Melo, Uphie Chinje; Kamseu, Elie

doi:10.1016/j.ceramint.2018.01.232

Cited by 17 publications

(13 citation statements)

References 40 publications

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“…Figure 4 and Table 3 detail the pore size distribution and the average pore radius of the porous ceramic matrix (PK3, PK4 and PK5) sintered between 1200 °C and 1400 °C. The general observations regarding the porosity of the kyanite-based porous mullite composites were linked to the increase in the volume of pores with the rise of the kyanite content up to 1275 °C [8]. This corresponds to a multimodal pore size distribution with the average pore size that increases from 3.22 to 3.25 µm between 1200 and 1275 °C (Table 1).…”

Section: Pores Size Distribution and Their Interconnectionmentioning

confidence: 92%

“…At high temperature, the cumulative pore volume decreased from ~ 120 to ~ 100 mm 3 g −1 for the PK3 series. PK4 presented 128.6 mm 3 g −1 , while PK5 147.7 mm 3 g −1 [8]. The reduction of the pore volume in the PK3 matrix is linked to the fact that the added kyanite was yet enough to hinder the formation of the glassy phase.…”

Section: Pores Size Distribution and Their Interconnectionmentioning

confidence: 97%

“…It is also important to control the amount and consistency of the glassy phase produced upon sintering to guarantee the presence of the fine well-interconnected pores network. In a previous work [8], the presence of interconnected pores with the size between 3 nm and 4.5 µm was achieved by producing a glassy phase with low thermal expansion coefficient starting from kaolin, bauxite, feldspar and kyanite [8]. It was shown that the presence of kyanite delayed the vitrification at relatively low temperature and improved the formation of mullite at high temperature, thus allowing the maintenance of certain porosity in a mechanically stable matrix.…”

Section: Introductionmentioning

confidence: 99%

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Semi-vitrified porous kyanite mullite ceramics: Young modulus, microstructure and pore size evolution

et al. 2019

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Microporous porcelain formulations are successfully carried out through sintering processing. During the thermal treatment of ceramic products, it was found that the addition of kyanite together with ϕand γ-Al 2 O 3 allowed to enhance interconnected pores network with micrometric size from 0.1 to 9 µm in a semi-vitrified composite. Between 1200 and 1350 °C, the mullitization of kyanite hindered the extension of vitrification and the growth of acicular mullite from the transformation of metakaolin. The main pores size decreased from 4.33 to 1.54 µm for the formulation containing 32 wt% of kyanite. In this interval the specific pore area increased from 0.64 to 8.75 m 2 g −1 due to the total conversion of the kyanite to fibrous and acicular mullite that reduced the voids provided by the earlier mullitization. The improvement in the mullitization without extensive vitrification and grain growth and the reduction of the pores size with the increase in the specific pore area contributed to the formation of a microporous matrix with the Young's modulus increased from 7 to > 20 GPa. The microstructure of the microporous porcelain, their specific pore area and pores size as well as the interconnection of pores was found innovative for the applications in the field of engineering filtration where high mechanical strength, strain, stiffness and pressure resistance are required.

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Section: Pores Size Distribution and Their Interconnectionmentioning

confidence: 92%

Section: Pores Size Distribution and Their Interconnectionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Semi-vitrified porous kyanite mullite ceramics: Young modulus, microstructure and pore size evolution

et al. 2019

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“…The mechanical performance of the cold setting refractory composite disks was evaluated using the piston-on-three ball method [ 18 ]. The tests were carried out at room temperature with a universal mechanical testing machine (MTS810, USA), with load cell of 100 kN and actuator speed of 1mm/min.…”

Section: Methodsmentioning

confidence: 99%

“…Mullite (3Al 2 O 3 ·2SiO 2 ), cordierite (Mg 2 A l4 Si 5 O 18 ) and kyanite (Al 2 SiO 5 ) can represent alternative and inexpensive solutions for reinforcing phases [ 17 , 18 , 19 ]. Kyanite is a polymorph that transforms at high temperature into mullite, with a small amount of liquid phase between the particles.…”

Section: Introductionmentioning

confidence: 99%

Controlling the Thermal Stability of Kyanite-Based Refractory Geopolymers

2021

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The present project investigated the thermal stability of cold-setting refractory composites under high-temperature cycles. The proposed route dealt with the feasibility of using fillers with different particle sizes and studying their influence on the thermo-mechanical properties of refractory geopolymer composites. The volumetric shrinkage was studied with respect to particle sizes of fillers (80, 200 and 500 µm), treatment temperature (1050–1250 °C) and amount of fillers (70–85 wt.%). The results, combined with thermal analysis, indicated the efficiency of refractory-based kyanite aggregates for enhancing thermo-mechanical properties. At low temperatures, larger amounts of kyanite aggregates promoted mechanical strength development. Flexural strengths of 45, 42 and 40 MPa were obtained for geopolymer samples, respectively, at 1200 °C, made with filler particles sieved at 80, 200 and 500 µm. In addition, a sintering temperature equal to 1200 °C appeared beneficial for the promotion of densification as well as bonding between kyanite aggregates and the matrix, contributing to the reinforcement of the refractory geopolymer composites without any sign of vitrification. From the obtained properties of thermal stability, good densification and high strength, kyanite aggregates are efficient and promising candidates for the production of environmentally friendly, castable refractory composites.

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