Control of continuous α-Al2O3 fibers by self-seeding and SiO2-Sol doping

Li, Xiangdong; Xu, Hui; Wang, Qi; Li, Siwei; Xiao, Han; Zhang, Li; Tang, Ming; Chen, Lifu

doi:10.1016/j.ceramint.2019.03.101

Cited by 19 publications

(6 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For example, when the volume ratio of aluminum to formic acid is 1:3, aluminum triformate (Al[O 2 CH] 3 ) could be obtained, which has been proved by using X-ray diffraction (XRD). [42,43] Moreover, by using FT-IR, 13 Figure 5. Due to the presence of coordinating water molecules close to the carboxylate group, the product OH-HCOO-IM3 (OH-CH 3 COO-IM3) may be partially hydrolyzed by this coordinating water molecule to generate the product OH-HCOO-IM5 (OH-CH 3 COO-IM5), and the energy barrier of this hydrolysis process is 88.3 kJÁmol −1 (80.0 kJÁmol −1 ).…”

Section: +mentioning

confidence: 99%

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

Liu

Wang

et al. 2020

Int J of Quantum Chemistry

View full text Add to dashboard Cite

In-depth studies of the structure of precursor sols is very important for understanding the subsequent sol to gel transition. Here, density functional theory was applied to study the reaction of Al powder with formic and acetic acid in aqueous solution to find the structure of Al(III) complex in precursor sols. The Al 3+ ion obtained by dissolving Al powder in aqueous solution of formic and acetic acid would preferentially coordinate with water molecules to form aluminum hydrates. As the reaction energy barrier of aluminum hydrates with CH 3 COO − and HCOO − was comparable, both aluminum formoacetate and other aluminum carboxylate monomers could be obtained. Most Al(III) complexes formed by other carboxylate monomers were similar to that prepared from aluminum formoacetate. However, some Al(III) monomers and Al(III) dimer with different structural characteristics might be detrimental to the formation of linear polymers. The formation of other aluminum carboxylate monomers had great influence on the structure of precursor sols.

show abstract

Section: +mentioning

confidence: 99%

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

Liu

Wang

et al. 2020

Int J of Quantum Chemistry

View full text Add to dashboard Cite

show abstract

“…Reducing the activation energy barrier of crystalline transformation by adding crystalline seeds during calcination, hence lowering the calcination temperature, has proven to be an effective method for the preparation of α-Al 2 O 3 particles at low temperature. [21][22][23][24][25][26] Kobayashi et al 22 added a small amount of α-Al 2 O 3 seeds to alumina sol and obtained α-Al 2 O 3 particles at less than 1100 • C. Yamamura et al 23 combined hydrothermal and sol-gel methods with α-Al 2 O 3 as seeds, and even reduced the crystallization temperature of α-Al 2 O 3 to 900 • C, but the obtained α-Al 2 O 3 contained some transition-phase alumina. Except for the self-seeding with α-Al 2 O 3 as seeds, some other crystallized materials such as γ-Al 2 O 3 , δ-Al 2 O 3 , and α-Fe 2 O 3 are also used as seed materials.…”

Section: Introductionmentioning

confidence: 99%

“…24,25 In addition, many studies have shown that incorporation of seeds can reduce the particle size and facilitate the obtaining of nanoparticles with narrower particle size distribution. 19,21,27,28 However, in the current research on the preparation of α-Al 2 O 3 particles by seeds method, researchers usually focus on reducing the initial crystallization temperature of α-Al 2 O 3 , while lacking attention to the homogeneity of phase and morphology of the final resulting particles. Meanwhile, the currently reported seeds such as α-Al 2 O 3 , γ-Al 2 O 3 , δ-Al 2 O 3 , and α-Fe 2 O 3 have limited effect on the reduction of calcination temperature of α-Al 2 O 3 .…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Except for the self‐seeding with α‐Al 2 O 3 as seeds, some other crystallized materials such as γ‐Al 2 O 3 , δ‐Al 2 O 3 , and α‐Fe 2 O 3 are also used as seed materials 24,25 . In addition, many studies have shown that incorporation of seeds can reduce the particle size and facilitate the obtaining of nanoparticles with narrower particle size distribution 19,21,27,28 . However, in the current research on the preparation of α‐Al 2 O 3 particles by seeds method, researchers usually focus on reducing the initial crystallization temperature of α‐Al 2 O 3 , while lacking attention to the homogeneity of phase and morphology of the final resulting particles.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Preparation of spherical α‐Al₂O₃ nanoparticles by microwave hydrothermal synthesis and addition of nano‐Al seeds

Wang

Mai

et al. 2022

J Am Ceram Soc.

View full text Add to dashboard Cite

Due to their special appearance, spherical α‐Al2O3 nanoparticles play an important role for obtaining high‐performance structural and functional ceramics. However, there are still problems such as easily agglomerates to form worm‐like structures at high temperatures and difficult availability of spherical nanoparticles. In this study, spherical α‐Al2O3 nanoparticles with high dispersion were prepared by a combination of a microwave hydrothermal method and an addition of nano‐Al particles as seeds. First, spherical amorphous alumina precursors were synthesized by the microwave hydrothermal method at 100°C for 30 min using Al2(SO4)3·18H2O, Al(NO3)3·9H2O, and urea, as raw materials, and then spherical α‐Al2O3 nanoparticles with a diameter of about 66 nm were acquired after calcined the precursor at 1050°C for 90 min by adding nano‐Al seeds, which reduced the calcination temperature by 50°C and holding time by 30 min compared to that without seeds. Kinetic analysis shows that 5 wt.% nano‐Al seeds can reduce the activation energy of crystalline transition of γ‐Al2O3 to α‐Al2O3 from 516.51 to 474.37 kJ/mol. Moreover, the microscopic mechanism of nano‐Al particles as seeds was investigated. The characterizations of sintering properties show that spherical α‐Al2O3 nanoparticles facilitate the acquisition of uniform microstructure for resulting ceramic and the fracture modes include both intergranular and transgranular fractures.

show abstract

Comparing the phase transformation of continuous alumina fiber and xerogels derived from the same precursor

Cheng

Liu

Yao

et al. 2021

J Sol-Gel Sci Technol

View full text Add to dashboard Cite

Control of continuous α-Al2O3 fibers by self-seeding and SiO2-Sol doping

Cited by 19 publications

References 36 publications

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

Preparation of spherical α‐Al₂O₃ nanoparticles by microwave hydrothermal synthesis and addition of nano‐Al seeds

Comparing the phase transformation of continuous alumina fiber and xerogels derived from the same precursor

Contact Info

Product

Resources

About

Control of continuous α-Al2O3 fibers by self-seeding and SiO2-Sol doping

Cited by 19 publications

References 36 publications

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

A density functional theory study on the structure formation of Al(III) carboxylate complexes in aqueous aluminum sols

Preparation of spherical α‐Al2O3 nanoparticles by microwave hydrothermal synthesis and addition of nano‐Al seeds

Comparing the phase transformation of continuous alumina fiber and xerogels derived from the same precursor

Contact Info

Product

Resources

About

Preparation of spherical α‐Al₂O₃ nanoparticles by microwave hydrothermal synthesis and addition of nano‐Al seeds