JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 6
·2482-2491
·
IF 2.841
Ming Xiang,Youfu Zhou,Wentao Xu,Decai Huang,Kun Wang,Wei Pan
Aluminum nitride (AlN) nanopowders have been synthesized by a novel method which combines the hydrothermal and carbothermal techniques. The phase of the nitridation products can be controlled through adjusting the carbon content of precursor by adding different amount of urea (U). The nitridation product synthesized from the precursor (U/Al=2) was comprised of spherical and well-distributed particles with sizes ranging from 50 to 100 nm. The nitridation procedure was investigated in detail with TG/DSC, XRD, and TEM measurements. It was found that the core-matrix structured Al 2 O 3 /C mixture presents after pyrolysis, favoring the nitridation completed at low temperature, and brings in temperature independency for AlN grain size. Finally, the additive-free AlN ceramic with 99.08% relative density has been achieved by pressureless sintering at 1850°C.
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
Desalination and Water Treatment
·
2016
·
IF 1.272
Wei-fang Chen,Chang-cheng Yan,Qiong Wang,Ling Pan,Li-fang Chen
Activated carbon-supported nano zero valent iron was synthesized through a carbonthermal reduction process. Specifically, iron-impregnated activated carbon was thermally treated under N2 atmosphere at temperatures ranging from 350 to 1,150°C. Major properties of the synthesized materials were obtained through analysis of iron content, BET surface area, and pore size distribution. TEM images, X-ray diffraction (XRD), and Fourier transform infrared patterns were also obtained for characterization. Results show that zero valent iron was reduced from iron oxide and those nanoparticles were highly dispersed based on TEM images while XRD patterns indicate a progressive reduction of iron oxide to form elemental iron. Treatment temperature greatly impacted the characteristics of the carbonthermal products. The size of the particles, content of elemental iron, surface functional groups, and pore structure all changed with the change in treatment temperature. Synthesized materials were tested for their reactivities on chromate. Reduction of Cr(VI) by carbothermal products occurred based on analysis of Cr speciation. In addition, reduction ability differed with various carbothermal temperatures. Overall, materials synthesized at 550–750°C appears to stand out when chromate removal capability and removal rate are concerned.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Xiongzhang Liu,Hui Luo,Jiaji Yang,Xian Wang,Zewen Qu,Heng Luo,Rongzhou Gong
TiB 2 –MgO microwave absorbing materials with TiB 2 as the absorber, MgO as the matrix are prepared by spark plasma sintering (SPS). The influences of commercial TiB 2 content and sintering temperature on dielectric and microwave absorption (MA) properties are studied. Besides, to optimize the MA performance, TiB 2 –MgO composite containing TiB 2 synthesized by the carbonthermal process is prepared. Meanwhile, its high-temperature dielectric and MA properties are investigated. Indeed, both the commercial TiB 2 content and sintering temperature play key roles in dielectric and MA properties, as they reaching 8 wt% and 1400 °C, the composite presents the optimal MA performance. For composite with synthetic TiB 2 as the absorber, the temperature has a positive effect on dielectric and MA properties. The enhanced high-temperature MA properties with minimum reflection loss ( RL min ) of −52.11 dB at 1.6 mm under 500 °C and effective absorption bandwidth (EAB, RL < −5 dB) of 4.2 GHz at 1.4–1.6 mm under 800 °C are obtained, which is mainly attributed to the temperature-dependent interfacial polarization compared to the temperature-insensitive conductivity. The excellent mechanical properties (flexural strength = 212.48 MPa), thin absorbing layer (d < 2 mm), enhanced thermal stability and high-temperature MA properties indicate that the TiB 2 –MgO composites can be considered as new candidates for high-temperature structure microwave absorbing materials.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Desalination and Water Treatment
·
2024
·
IF 1
Wei-fang Chen,Weipeng Lu,Sijia Zhang,Xiaobing Xie,Fei-fei He,Zai Chen
Starting with sucrose and ferrous chloride, nanoparticles of iron encapsulated in carbon structure were synthesized using a carbothermal method. The effects of carbothermal temperature, treatment time, Fe:sucrose mass ratio on the properties of the nanoscale zero-valent iron supported activated carbon were investigated. Temperatures ranged from 500°C to 1,100°C and treatment time used was 0.5, 1 and 3 h. Mass ratios of Fe and sucrose were 1:2, 1:4 and 1:8, respectively. Materials thus obtained were mostly powdered. X-ray diffraction patterns indicate that zero-valent iron was successfully produced from reduction of iron oxides. Iron was incorporated into the carbon structure. Hexachlorobenzene was employed as the target substance to test the material’s application. The optimum synthesis condition which resulted in a more than 95% HCB removal was carbothermal temperature of 700°C, treatment time of 1 h and mass ratio of Fe:sucrose of 1:4.
研究领域:
环境化学
·
材料科学
·
环境污染治理
·
纳米材料
·
环境工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）