JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2021
·Vol. 99
·期 1
·169-177
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IF 2.326
Cheng Ming,Liu Wensheng,Yao Shuwei,Wang Juan,Ma Yunzhu
Phase transformation is essentially important for the microstructures and properties of sol–gel prepared alumina fiber and powders. In this study, alumina precursor fiber and xerogels were prepared using the same aluminum carboxylate sol. The phase transformation and microstructure evolution of the precursor fibers and xerogels were investigated using TG-DSC, XRD, TEM, and SEM methods. The alumina precursor fiber and xerogels have similar chemical structures and Al(III) species. After preheated at 600 °C, most of the free water molecules, hydroxyl groups, nitrate acid radical, formic acid radicals, and acetic acid radicals are removed from the alumina precursor fiber and xerogels. The preheated fiber and xerogels exhibit amorphous phases. From the TG-DSC curves, the transformation temperature from γ-Al 2 O 3 to α-Al 2 O 3 in the preheated fiber is 30 °C lower than that in the preheated xerogels. The TEM results suggest that the fiber calcined at 1000 °C for 1 h can be completely transformed into α-Al 2 O 3 phase, while the xerogels need to be calcined at 1100 °C for 1 h to completely convert into the α-Al 2 O 3 phase. The difference in the phase transformation of the alumina fiber and xerogels was discussed in this paper.
研究领域:
材料科学
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陶瓷学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Huan Xu,Cui Liu,Wei Guo,Nian Li,Yang Chen,Xiaolin Meng,Mengjie Zhai,Shudong Zhang,Zhenyang Wang
The severe environmental pollution issues require the urgent development of new green building insulation materials. Biomass aerogel is deemed as an optimal candidate to replace petroleum-based insulation materials owing to its significant advantages such as low thermal conductivity, eco-friendliness, and high biocompatibility. The interaction of the composite two-phase interface and the fabrication of multilevel pore structures have a significant impact on the comprehensive performance of aerogel applications. In this study, a tunable double-crosslinked network skeleton structure construction of sodium alginate (SA) composite with Al 2 O 3 fibers is proposed, where Ca 2+ induces the sol–gel transition to form a second layer of strong bonding force to effectively support the skeleton structure, and various cross-linking modes, such as ionic bonding, hydrogen bonding and physical cross-linking, are used to synergistically improve the SA aerogel and endow it with multifunctionality. The prepared Al 2 O 3 fiber/SA (SAA) aerogels achieve excellent flame retardancy and self-extinguishing smoke suppression (peak heat release rate as low as 9.7 kW m −2 , and total smoke release rate in the low range of 0.5 m 2 m −2 ). It also has superior mechanical strength (high specific compression modulus of ∼53.3 KN m kg −1 ) and can withstand weights over 2600 times its own weight without deformation, besides the broad range of self-cleaning properties and outstanding biocompatibility. The creation of a double-crosslinked three-dimensional aerogel network via reinforcement of inorganic electrospun fibers provides new insights for eco-friendly insulation materials in construction.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Transactions of the Indian Ceramic Society
·
2022
·
IF 2.355
Qiang Liu,Juan Wang,Wensheng Liu,Lingjiao Zhan,Shaoheng Peng,Shuwei Yao,Yunzhu Ma
In order to optimize the phase composition and grain size of alumina fibers, 0-3 wt% SiO2 were induced to prepare alumina fibers using sol-gel method with the reaction of aluminium powder, formic acid, acetic acid, nitric acid and SiO2 sol. Effects of low SiO2 content on the phase transition and microstructure of alumina fibers were investigated. X-ray diffraction analysis and differential scanning calorimetry results showed that the addition of silica delayed the formation of α-Al2O3, and the phase transformation path of alumina was changed from amorphous alumina → γ-Al2O3 → α-Al2O3 to amorphous alumina → γ-Al2O3 → θ-Al2O3 → α-Al2O3. Moreover, scanning electron microscopy and transmission electron microscopy results confirmed that the addition of SiO2 reduced the grain size and was beneficial for the dense structure. Fine-grained dense alumina fibers composed of α-Al2O3 phase and transitional alumina phase were obtained by adding 1 wt% and 3 wt% silica after sintering at 1200°C for 1 h.
研究领域:
材料科学
·
陶瓷学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Chen Liang,Wensheng Liu,Qiang Liu,Yangrui Gao,Jijin Liu,Juan Wang,Shuwei Yao,Yunzhu Ma
Thermal decomposition is a critical process for fabricating alumina fibers using sol-gel methods. In this work, effects of preheating time on microstructure of prepared alumina fibers were studied. Results showed that core-sheath structure formed in the fibers when holding time exceeded 2 h at 400 °C. The fibers having core-sheath structure after thermal decomposition showed more residues, smaller crystal grain size and lower density. Thermal decomposition and densification of fibers were investigated. Results showed that core-sheath structure formed because fiber surface and core underwent different decomposition reactions due to the reduction in the number of gas channels on the fiber surface. This work provides a comprehensive study of thermal decomposition of precursor fibers and provides guidelines for developing appropriate calcination schedules.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Peisen Liu,Xueying Zhang,Yunjia Xue,Anran Guo,Liachen Liu
A heat resistance adhesive with wide operative temperature range for bonding alumina fiber fabric was developed by organic-inorganic modification. The polyvinyl alcohol modified by B 2 O 3 generated a complex cross-linked network connected by B–O–C bonds, which can enhance the bonding strength of adhesive after heat-treatment from RT to 400 °C. Moreover, the addition of B 4 C can enhance the bonding strength of adhesive after heat-treatment from 400 °C to 800 °C due to the formation of molten B 2 O 3 and borosilicate glass . Significantly, the appropriate addition of B 4 C can make the adhesive form a denser structure without transforming the fracture mode of the bonding joints, which is conducive to enhance the strength performance of bonding joints after sintered at 800 °C. On the contrary, the excessive addition of B 4 C will transform the fracture mode of the bonding joints into brittle fracture , which will degrade the strength performance of bonding joints.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2021
·
IF 7.664
Li Fan,Shuai Zhang,Guojie Zhao,Qiang Fu
Various fillers and methods have been utilized to enhance the thermal conductivity ( TC ) of polymer-based electronic packaging materials, however, the enhancement was limited by disconnected pathway for phonon transferring. Herein, a novel fibrillated hybrid skeleton (f-AO@BNNS skeleton) was fabricated by dispersing boron nitride nanosheet (BNNS) into alumina (AO) sol, electrospinning and sintering, where long-range phonon transferring highway was successfully constructed by both macroscopically interconnected fiber and microscopically oriented and overlapped BNNSs confined in nanofiber . Besides, crystal AO and atomic-level bonding were acquired on BNNS-AO interface by sintering, largely decreasing interface thermal resistance inside skeletons. Prepared polybenzoxazine/f-AO@BNNS composites exhibited the highest TC of 3.24 Wm −1 K −1 at a skeleton loading of 6.9 vol%. The higher TC was achieved at lower filler content when compared with other reported skeletons, demonstrating the superiority of f-AO@BNNS skeleton. This work provides a new strategy of preparing fibrillated hybrid skeleton for high thermally conductive composites.
研究领域:
材料科学
·
热物理学
✓ 已验证
产品关联
DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2012
·
IF 1.867
Guoxin Hu,Bo Tang,Xia Min
By using layer-by-layer self-assembly technology, multilayered films consisting of alternated humic acid and Fe 3 + ions ((HA/Fe 3 + ) n , n = 10,20,40) were fabricated on alumina fiber (AF) substrate for the first time. FTIR and FESEM results show that the (HA/Fe 3 + ) n thin films were effectively immobilized on the AF surface. The average thickness of a single bi-layer HA/Fe 3 + is not sensitive to the total layers. On the contrary, the concentration of Fe 3 + ions significantly influences this mean thickness. A loose and amorphous structure with some irregular pores was detected from the as-prepared specimens, while relatively smooth surface and denser structure were observed after carbonized at 1000 °C. The large BET surface areas and excellent absorbability of the as-prepared and carbonized samples were found. Moreover, at room temperature, a ferromagnetic property of these samples was revealed by magnetism testing. Due to the adjustable number of layers, the ferromagnetic property is controllable. Therefore, these produces possess potential application as the support material in catalytic and target drug delivery areas.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2025
·
IF 4.2
Guangxu Zhao,Jingjing Zhang,Peng Wang,Xiaoyu Feng,Guishan Liu
Water is a typical impurity in organic solvents, and the detection of trace amounts of water in organic solvents is of great significance both in the chemical field and industrial applications. This work described an innovative preparation method of rare earth europium (Eu 3+ ) complexes being grafted on the surface of alumina fibers, which successfully prepared fluorescent alumina fibers and were used as fluorescent probes to detect water in organic solvents. The alumina fibers were prepared by electrostatic spinning, then the surface of alumina was modified by silane coupling agent (APTES) with maleic anhydride (MAH), and finally rare earth europium complexes was grafted on the surface of alumina fibers. The results showed that the rare earth complexes successfully grew on the alumina surface and bonded with –OH on the alumina surface. The addition of water resulted in an overall quenching of the fluorescence intensity of the fluorescent alumina fibers, with detection limits of 0.079 % v/v, 0.121 % v/v, and 0.062 % v/v in ethanol, DMF, and acetone solutions, respectively. This paper provides an innovative approach and methodology for the study of water content detection in organic solvents. This research broadens the potential applications of alumina fibers in functionalization.
研究领域:
材料科学
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化学工程
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2020
·Vol. 13
·期 23
·5442
·
IF 3.057
Luqun Liu,Juan Wang,Yunzhu Ma,Wensheng Liu,Shuwei Yao
Continuous alumina fiber exhibits excellent mechanical properties owing to its dense microstructure with fine grains. In this study, alumina fiber was prepared by the sol–gel method using iron sol as a nucleating agent. It was proposed that the α-Al2O3grain size be adjusted based on the modification of colloidal particle size. The effect of holding temperature and reaction material ratio on the iron colloidal particle size was studied. The microstructure of alumina fiber was characterized by scanning electron microscopy (SEM). The experiment results indicated that iron colloidal particle size increases with the holding temperature and the NH4HCO3/Fe(NO3)3·9H2O ratio. The alumina fiber with uniform nano α-Al2O3grains was obtained by calcination at 1400 °C for 5 min. The mean grain size tends to rise with the mean colloidal particle size. Using the iron sol as a nucleating agent, the fiber with a mean grain size of 22.5 nm could be formed. The tensile strength of fibers increased with the decrease of grain size.Keywords:alumina fiber;iron sol;holding temperature;colloidal particle size;grain size
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zhengdong Li,Xueying Zhang,Liwen Yan,Haiyan Du,Anran Guo,Ying Mu,Jiachen Liu
High emissivity coatings on hypersonic vehicle surfaces dissipate heat by emitting thermal radiation. While the difficulty of increasing emissivity limits the performance of coatings to improve heat-dissipation of the thermal insulation felt. Herein, a novel high-reflectivity and high-emissivity integrated double-layer coating was developed to enhance the thermal insulation performance of the alumina fiber fabric. The coating comprised of TiO 2 @SiO 2 (T@S) as reflective agent and ZrO 2 /SiC w (ZSC) as emittance agents, was applied on the surface of alumina fiber fabric (AFF). The reflecting effect of radiation heat from the high reflective agent enhanced the thermal insulation properties of the double-layer coating. In the wavelength range of 0.4–2.5 μm, the average emissivity of the ZSC coating was 0.83 and the average reflectivity of the T@S coating was 0.63. With continuous heating at 1400 °C for 10 min with a butane torch, the temperature on the backside of the T@S–ZSC-coated AFF remained relatively stable at 225 °C, which is notably decreased by 80 °C compared to that of the single-layer ZSC-coated AFF. The tensile strength of AFF with T@S–ZSC coating reached 35 MPa after being heat treated at 1200 °C. Moreover, the bonding strength between the coating and the AFF substrate was measured to be 0.15 MPa. The double-layer coating with high emissivity and reflectivity, along with a flexible AFF substrate, offers a promising solution for addressing the challenging of surface heat-dissipation in hypersonic vehicles.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED PHYSICS LETTERS
·
2013
·Vol. 102
·期 25
·
IF 3.794
Zhou Yongcun,Bai Yuanyuan,Yu Ke,Kang Yan,Wang Hong
A polymer based composite was prepared by using modified aluminum fibers and aluminum nanoparticles as fillers in polyimide matrix that resulted in the high thermal conductivity and low relative permittivity. It was found that silica coated aluminum fibers with the multilayer coating structures can significantly reduce the relative permittivity (about 19.6 at 1 MHz) of the composite while keeping lower dielectric loss (0.024 at 1 MHz). The thermal conductivity of composites was significantly increased to 15.2 W/m K. This work shows a useful way to choose proper modifier fillers to improve the composite properties for electronic packaging composite materials.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2022
·Vol. 103
·期 1
·125-138
·
IF 2.606
Ma Yunzhu,Peng Shaoheng,Liu Wensheng,Yao Shuwei,Wang Juan
Controlling the density and the nanograin size is challenging but essential to prepare continuous alumina fibers with excellent performance. In this study, the continuous alumina fibers were prepared using the sol-gel method. The fibers calcined under different conditions were characterized to reveal the effect of calcining conditions on the fiber microstructure evolution. The results show that the phase transformation from amorphous Al 2 O 3 to γ-Al 2 O 3 and then to α-Al 2 O 3 takes place during the calcining process. The fiber, prepared using a single-step calcining method, cannot obtain a fully dense and nanocrystal microstructure through optimizing the calcination conditions. Thus, a novel two-step calcining process was proposed, through which an almost fully dense α-Al 2 O 3 fiber with an average grain size of ~150 nm was prepared and the tensile strength of fibers reaches 2.2 GPa. Based on the results, the effect mechanism of residual organics, phase transformation, densifying, and grain growth on the fiber microstructure evolution was discussed in depth.
Graphical abstract
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）