Low-temperature synthesis of highly porous whisker-structured mullite ceramic from kaolin

Ma, Jie; Ye, Feng; Zhang, Biao; Jin, Yicheng; Yang, Chunping; Ding, Junjie; Zhang, Haoqian; Liu, Qiang

doi:10.1016/j.ceramint.2018.04.163

Cited by 31 publications

(37 citation statements)

References 46 publications

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“…Mullite ceramics are commonly synthesized from the Al 2 O 3 ‐SiO 2 ‐system using a fluorine‐containing catalyst (such as AlF 3 ) 12,15,19,20 . The growth of mullite whiskers in this system is considered to be a vapor‐solid (V‐S) growth mechanism 21 .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, calcined kaolin was chosen to provide SiO 2 in Al 2 O 3 ‐SiO 2 ‐system ceramics, and the molar ratio of Al 2 O 3 and SiO 2 was adjusted to control the content of mullite seeds in the system. As the most common ceramic in the Al 2 O 3 ‐SiO 2 ‐system, pure mullite (3Al 2 O 3 ·2SiO 2 ) has been previously studied by our team for applications in the field of radomes 12,20 . However, there is a lack of research on Al 2 O 3 ‐rich and SiO 2 ‐rich composite ceramics with a wider molar ratio of Al 2 O 3 ‐SiO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Sintering behavior and morphology control of porous Al ₂ O ₃ ‐SiO ₂ ceramics for radome applications

Ren

Zhang

Shao

et al. 2022

Int J Applied Ceramic Tech

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Ceramics from porous Si 3 N 4 and its derivatives SiAlON and Si 2 N 2 O were once considered the most promising high-temperature wave-transmitting materials. However, their large-scale application in the field of radomes is greatly restricted due to their poor oxidation resistance, high preparation costs, and expensive raw materials. Therefore, the development of low-cost porous oxide ceramics remains of significant interest to the field of high-temperature wave transmission. Surprisingly, mullite ceramics, which are representative of the Al 2 O 3 -SiO 2 -system of ceramics, are ultra-low-cost materials with the potential to replace ceramics from Si 3 N 4 and its derivatives. In this paper, integrated porous Al 2 O 3 -SiO 2 -system ceramics were successfully prepared for load-bearing/wavetransmitting applications, using inexpensive calcined kaolin and alumina powder as the main raw materials. Calcined kaolin can provide seeds for the growth and development of mullite crystals in the ceramic system. High-strength and high-porosity ceramics were obtained with the mullite morphology controlled through the molar ratio of Al 2 O 3 to SiO 2 and the resulting content of mullite seeds. With increasing of mullite seed content, the length and radial width of mullite whiskers with "interlocking structure" gradually change from rodshaped "long and thick" to needle-like "short and thin." The prepared porous Al 2 O 3 -SiO 2 ceramics have high flexural strength, fracture toughness, and good dielectric properties.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sintering behavior and morphology control of porous Al ₂ O ₃ ‐SiO ₂ ceramics for radome applications

Ren

Zhang

Shao

et al. 2022

Int J Applied Ceramic Tech

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“…Therefore, when a larger quantity of mullite is desired, it is necessary to add precursor sources rich in aluminum oxide to establish a higher ratio of Al 2 O 3 /SiO 2 [10,11]. Studies conducted by several researchers [12][13][14][15][16][17][18] had the purpose to obtain mullite from the sintering of clays and aluminum…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

et al. 2020

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The aim was to study formulations containing aluminosilicate and alumina in order to obtain compositions with suitable properties to fabricate dielectric ceramic devices. Initially, the precursors were subjected to chemical, mineralogical and granulometric characterization. The formulations were defined and specimens were pressed (19.6 MPa) in shapes of disc and rectangular bar. Specimens were dried, heat-treated at 1400, 1450 and 1500 °C and the mineralogical, morphological, physical, dielectric and mechanical properties were evaluated. The relative dielectric constant (εr) and loss tangent (tanδ) were evaluated at 0.1, 1, 10 and 100 kHz at room temperature. The mullite was the major phase for the studied temperature range. Compositions with a higher content of fluxes showed lower porosity and better dielectric properties and flexural strength. Values of εr at 1 kHz (~3.5 to 4.5) were close to that of the mullite for the samples fired at 1400 °C.

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“…7 Above all, mullite whisker is an effective reinforcement for composite materials because of whisker toughening. 8…”

Section: Introductionmentioning

confidence: 99%

“…7 Above all, mullite whisker is an effective reinforcement for composite materials because of whisker toughening. 8 Ceramic proppants can fracture when the stress reaches or exceeds a certain value. Previous studies have shown that the fracture of ceramic proppants was transgranular fracture rather than intergranular fracture.…”

Section: Introductionmentioning

confidence: 99%

Toughening effect of mullite whisker within low-density ceramic proppants

Hao

Gao

et al. 2019

Advanced Composites Letters

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Main crystal phases of low-density ceramic proppants prepared by bauxite and feldspar are granular corundum and whisker-shaped mullite. Mullite whiskers are interlocked with one another and piled up inside the pores. High aspect ratio of mullite whiskers inside the pores can greatly enhance the fracture toughness. The dominant toughening mechanism for the proppants is attributed to crack bifurcation and deflection and pulling out and bridging effect of mullite whiskers.

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Low-temperature synthesis of highly porous whisker-structured mullite ceramic from kaolin

Cited by 31 publications

References 46 publications

Sintering behavior and morphology control of porous Al ₂ O ₃ ‐SiO ₂ ceramics for radome applications

Sintering behavior and morphology control of porous Al ₂ O ₃ ‐SiO ₂ ceramics for radome applications

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

Toughening effect of mullite whisker within low-density ceramic proppants

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Low-temperature synthesis of highly porous whisker-structured mullite ceramic from kaolin

Cited by 31 publications

References 46 publications

Sintering behavior and morphology control of porous Al 2 O 3 ‐SiO 2 ceramics for radome applications

Sintering behavior and morphology control of porous Al 2 O 3 ‐SiO 2 ceramics for radome applications

Fabrication and characterization of dielectric ceramics using alumina and aluminosilicates

Toughening effect of mullite whisker within low-density ceramic proppants

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Product

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Sintering behavior and morphology control of porous Al ₂ O ₃ ‐SiO ₂ ceramics for radome applications

Sintering behavior and morphology control of porous Al ₂ O ₃ ‐SiO ₂ ceramics for radome applications