CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Huafei Cai,Yonggang Jiang,Jian Feng,Qu Chen,Sizhao Zhang,Liangjun Li,Junzong Feng
Silica aerogel is a typical nanoporous material exhibiting excellent thermal insulation property, and its nanostructure change at high temperature has attracted extensive attention. However, there is a lack of real-time research on the nanostructure evolution of silica aerogel under rapid heating. Here, silica aerogel was rapidly heated and imaged via an in-situ heating TEM to characterize the nanostructure evolution of from 600 °C to 1300 °C. After rapid heating at different temperatures, the silica aerogels were characterized by SEM, BET, TG-DSC, XRD and FT-IR. The nanostructure evolution of the aerogels can be divided into three temperature stages and experimental strategies for inhibiting aerogel shrinkage at high temperature can be provided. In stage Ⅰ (600 °C–1000 °C), the shrinkage of the silica aerogels occurred during the initial time of the heating process (within 2 h), and then the structure of silica aerogel became stable. The shrinkage of silica aerogels is primarily caused by the fusion of secondary particles, and increasing the secondary silica aerogel particle size may contribute to reducing the aerogel shrinkage. In stage Ⅱ (1100 °C), the aerogel shrinkage can be observed all the time with the heating process continues, and finally closed to the dense state. The shrinkage of silica aerogels is caused by the fusion of secondary particles and the macropore collapse, increasing the particle size and reducing the macropore content may slow down aerogel shrinkage. In stage Ⅲ (1200 °C–1300 °C), the aerogel will shrink rapidly and reach a dense state in a very short time (within 0.5 h). The shrinkage of silica aerogels is caused by the rapid pore collapse and the rapid fusion and shrinkage of the secondary particles of the aerogel, and pure silica aerogels cannot be used at this temperature.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
GOLD BULLETIN
·
2022
·Vol. 55
·期 2
·115-121
·
IF 1.564
Zhang Lin,Zhang Jianjun,Zheng Quan,Xu Ying,Kou Xinli,Li Tao
Although gold hollow spheres show unique advantages in fields like catalysis, the available synthesis strategies have low atom and economic efficiency. In this paper, Au hollow spheres were produced by combining simple wet chemical method and rapid heating–cooling process, in which rapid temperature rise caused Au evaporation and rapid cooling froze gold “bubbles.” The control experiments confirmed the presence of supports which limit the growth and sintering of Au nanoparticles to some extent, and slower heating rate inhibits the hollowing of gold sphere. This work provides a new strategy for the rapid and facile synthesis of Au hollow spheres, offering a wide range of possibilities for energy storage and biosensing applications.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2024
·Vol. 53
·期 8
·4613-4621
·
IF 2.2
Wang Hongjun,Yang Shuning,Zeng Xiong,Chen Mengyao,Guo Zicong,Mi Pengtao,Zhou Jing,Zhu Yuanyuan
Low-dimensional yttrium oxide (Y 2 O 3 ) nanostructures have garnered significant research interest due to their intriguing properties arising from the dimensional effect and the modulation of the band structure. However, the simple preparation of Y 2 O 3 nanosheets is rarely investigated due to the inherent limitations posed by the counterpart bulk cubic or monoclinic crystal structure. Herein, the low-dimensional layered Y 2 O 3 nanosheets are prepared by a facile route of rapid heating followed by centrifugation, in which its corresponding hydrous-chloride compound is used as the sole reagent. The formation stages of layered Y 2 O 3 nanosheets and corresponding mechanisms are elucidated in detail. The x-ray diffraction results confirm that the intermediate product after rapid heating is yttrium oxychloride (YOCl), which converts to the single-phase Y 2 O 3 with a 2D layered phase after centrifugation. In addition, the obtained Y 2 O 3 nanosheets possess a direct optical bandgap of 5.49 eV, and thus may hold promise for use in electronic applications. This research provides a facile and low-cost method for the preparation of other low-dimensional nanosheets with similar structures. Graphical Abstract
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2017
·
IF 4.873
Pengbo Lu,Fan Cheng,Yanghao Ou,Meiyan Lin,Lingfeng Su,Size Chen,Xilang Yao,Detao Liu
The thin flexible film heater made of carbon fibers is widely considered to be an ideal material for the use as self-heating devices because of its safe, low-cost, no noises, small size and fast heating as well as energy saving. Presently thin flexible film heater is mostly fabricated by mixing method using the long cellulose fibers as film-forming materials and carbon fibers as self-heating materials, which mostly suffer from opaque or uneven heating field. In this work, we firstly reported a flexible and transparent thin film heater (FTFH) composed of carbon fibers and regenerated cellulose . The use of regenerated cellulose for membrane materials brings high transmittance, strong adhesion , fast temperature response and high generated temperature. More importantly, the FTFH using novel carbon fibers as self-heating materials and regenerated cellulose as membrane materials show a rapid heating response (12 s), higher power density (2577 w/m 2 ) and long-term stability of generated temperature (162.3 °C).
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Polymer Materials
·
2022
·
IF 4.855
Shuaishuai Liu,Yanyan Wang,Chao Xiao,Miao Jiang,Xin Ding,Hui Zhang,Kang Zheng,Lin Chen,Xingyou Tian,Xian Zhang
Owing to superior comprehensive performance, polyimide film (PI) has been extensively used as flexible substrate to support and fix electronic components. However, the current PI film has inferior thermal conductivity, especially in the vertical direction, causing failure of electronic devices in overheating conditions. Herein, an electrically insulating pea-pod-like filler with high thermal conductivity in both horizontal and vertical directions was prepared by encapsulating interconnected carbon microsphere (CM) with graphene-like carbon nitride (g-C3N4). The resultant thermal conductivity of PI film in horizontal and vertical directions has been improved by 11 (1.98 W m–1 K–1) and 2.4 (0.43 W m–1 K–1) times at 30 wt % CM@g-C3N4 loading, respectively. Furthermore, benefiting from satisfactory light absorption of CM@g-C3N4, the PI/CM@g-C3N4 film displays rapid heating capability under illumination. Meanwhile, the PI/CM@g-C3N4 film keeps intrinsic electrical insulation, thermal and dimensional stabilities. This work provides an effective method to solve the bottleneck of the current PI film in inadequate thermal conductivity.
研究领域:
材料科学
·
纳米技术
·
热工程
·
高分子科学
✓ 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）