Processing, structure, and properties of mullite fiber/mullite matrix composites

Chawla, K. K.; Xu, Z.R.; Ha, Jung‐Soo

doi:10.1016/0955-2219(95)00136-0

Cited by 58 publications

(15 citation statements)

References 11 publications

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“…In order to avoid the formation of a strong interface between the fiber and the matrix due to chemical reaction during sintering, the fiber material can be pretreated to change the binding force between the fiber and the matrix [128]. The Boron Nitride (BN) coating with thickness of 1μm was prepared on the surface of Nextel TM 480 and Nextel TM 550 fibers by Chawla et al [129]. The mechanical properties of the coated fiber reinforced mullite composites are greatly improved, the bending strength reaches 258 and 223 MPa, respectively, and the fracture toughness is 8.5 and 6.0 MPa•m 1/2 , respectively.…”

Section: Dupontmentioning

confidence: 99%

Toughening Mechanism of Mullite Matrix Composites: A Review

Cui

Zhang

et al. 2020

Coatings

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Mullite has high creep resistance, low thermal expansion coefficient and thermal conductivity, excellent corrosion resistance and thermal shock resistance, and plays an important role in traditional ceramics and advanced ceramic materials. However, the poor mechanical properties of mullite at room temperature limit its application. In order to improve the strength and toughness of mullite, the current research focuses on the modification of mullite by using the second phase. The research status of discontinuous phase (particle, whisker, and chopped fiber) and continuous fiber reinforced mullite matrix composites is introduced, including preparation process, microstructure, and its main properties. The reinforcement mechanism of second phase on mullite matrix composites is summarized, and the existing problems and the future development direction of mullite matrix composites are pointed out and discussed.

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Section: Dupontmentioning

confidence: 99%

Toughening Mechanism of Mullite Matrix Composites: A Review

Cui

Zhang

et al. 2020

Coatings

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“…It has been widely used as reinforcements in ceramic matrix composites (CMCs) in the field of refractory, aerospace, and insulation 3–5 . It is usually defined as containing polycrystalline mullite (the pure mullite fiber), or a mixture of γ‐Al 2 O 3 plus amorphous SiO 2 with mullite composition that can be transformed to mullite at a determined temperature (the unreacted Al 2 O 3 –SiO 2 mullite fiber) 6–8 . The pure mullite fiber is free of glass phase (amorphous SiO 2 ) and is composed of nearly pure mullite with fewer γ‐Al 2 O 3 grains.…”

Section: Introductionmentioning

confidence: 99%

Microstructure evolution and mechanical behavior of a mullite fiber heat‐treated from 1100 to 1300°C

et al. 2021

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In this paper, the effect of phase transformation on microstructure evolution and mechanical behaviors of mullite fibers was well investigated from 1100 to 1300 • C. In such a narrow temperature range, the microstructure and mechanical properties showed great changes, which were significant to be studied. The temperature of the alumina phase transformation started at below 1100 • C. The main phases in fibers were γ-Al 2 O 3 and δ-Al 2 O 3 with amorphous SiO 2 at 1150 • C. The stable α-Al 2 O 3 formed at 1200 • C. Then the mullite phase reaction occurred. As the alumina phase reaction took place, the tensile strength increased with the increasing temperature. In particular, the filaments achieved the highest strength at 1150 • C with 1.98 ± 0.17 GPa, and the Young's modulus was 163.08 ± 4.69 GPa, showing excellent mechanical performance. After 1200 • C, the mullite phase reaction went on with the crystallization of orthorhombic mullite. The density of surface defects increased rapidly due to thermal grooving, which led to mechanical properties degrade sharply. The strength at 1200 • C was 1.01 ± 0.15 GPa with a strength retention of 63.13%, and the Young's modulus was 184.14 ± 10.36 GPa. While at 1300 • C, the tensile strength was 0.64 ± 0.14 GPa with a strength retention of only 40.00%.

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“…Mullite (3Al 2 O 3 ·2SiO 2 ) fibers have excellent high‐temperature strength, creep resistance, and chemical stability . Thus they have been widely used as the reinforcement in the ceramic matrix composites . These fibers can also be used as the high‐temperature thermal or electrical insulating materials .…”

Section: Introductionmentioning

confidence: 99%

Mullite–Nickel Magnetic Nanocomposite Fibers Obtained from Electrospinning Followed by Thermal Reduction

Chen

Aprelev

et al. 2016

J. Am. Ceram. Soc.

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Mullite-nickel nanocomposite fibers with Ni nanoparticles of controllable size, dispersion, and consequent magnetic properties were fabricated using sol-gel/electrospinning method, followed by thermal reduction. The fibers were electrospun from an aqueous solution containing sol-gel mullite precursor and nickel nitrate. These fibers were then heat treated in the reducing atmosphere between 550°C and 750°C to achieve fine-dis persed metallic Ni nanoparticles (NPs). After the Ni 2+ was reduced to Ni NPs at 750°C for 10 h, the fibers were then directly transformed to the mullite fibers at 1000°C without the undesirable intermediate spinel phase. In many high-temperature applications, mullite is the desired phase than spinel. If not fully reduced, the Ni 2+ cations induce early precipitation of spinel phase before mullite can be formed. This spinel phase was a solid solution between Al 2 NiO 4 and Al-Si spinels, which later reacted with the residual silica and formed a mixture of mullite and spinel at 1400°C. The formation of spinel phase was suppressed or fully eliminated with chemically reducing Ni 2+ to metal NPs. The average size of nickel NPs within the fibers was~20 nm, insensitive of the Ni concentration and reducing temperature. However, the Ni NPs on the fiber surface grew as large as~80 nm due to fast surface diffusion. The magnetic nanocomposites exhibited ferromagnetism with saturation magnetization (M s ) close to pure nickel of the same nominal weight, but coercivity (H c ) much smaller than the bulk nickel, indicating the nature of bimodal magnetic nanoparticle distributions. The majority of small Ni NPs (~20 nm) within the fibers exhibited superparamagnetism, while the minor portion of relatively large NPs (50-80 nm) showed ferromagnetism.

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Processing, structure, and properties of mullite fiber/mullite matrix composites

Cited by 58 publications

References 11 publications

Toughening Mechanism of Mullite Matrix Composites: A Review

Toughening Mechanism of Mullite Matrix Composites: A Review

Microstructure evolution and mechanical behavior of a mullite fiber heat‐treated from 1100 to 1300°C

Mullite–Nickel Magnetic Nanocomposite Fibers Obtained from Electrospinning Followed by Thermal Reduction

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