Arabian Journal of Chemistry
·
2022
·Vol. 15
·期 9
·104071
·
IF 6.212
Ruoshui Liu,Di'an Wu,Xiang Yu,Ningfang Zhou,Dan Liu,Lichen Wang,Zhiyi Xu,Huayang Gong,Tongyun Zhao,Jirong Sun,Fengxia Hu,Baogen Shen
Sintered polycrystalline strontium hexaferrite, which is one of the most widely used permanent magnetic materials, has been applied in many areas such as electrical and mechanical transductor devices. Improving the coercivity ( H cJ ) of M-type strontium hexaferrite with a nominal composition SrFe 12 O 19 (SrM) plays an essential role to adapt to many modern applications, but is limited by the process and purity of raw materials. In this work, we prepared SrM powders with different iron resources, sintering temperatures, and Fe/Sr atom ratios. It was found that using Fe 3 O 4 nanoparticles with a Fe/Sr atom ratio of 12 at 1100 °C performed the self-composites with 70% nano-size and 30% micro-size, which had the best performance. The coercivity reaches 348.9 kA/m, which is improved compared to pure SrM obtained by other iron resources in the solid-state method. This process shows a unique formation mechanism and the resulting self-composite microstructure eventually causes enhancement in the properties, which provides a new way for high-performance hexaferrites.
研究领域:
材料科学
·
磁学与磁性材料
·
陶瓷
·
纳米材料
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·Vol. 50
·期 23
·51687-51692
·
IF 5.1
Fengsheng Zeng,Jiuyuan Han,Guoyun Shao,Rengang Shi,Raz Muhammad,Yuanyuan Zhang,Fayaz Hussain,Hadi Barzegar Bafrooei,Ehsan Taheri-Nassaj,Kaixin Song
In this paper, different divalent ions (X = Ni, Cu, Mg, Co, Zn) are doped to replace Mg 2+ at the tetrahedral sites in mixed spinel Mg 0.95 X 0.05 Al 2 O 4 . These substitutions induce variations in the degree of inversion/preferential occupation at the A/B lattice site in MgAl 2 O 4 ceramics because the octahedral stabilization energies change as a function of dopant . According to crystal field theory , the number of d -orbital electrons has a significant impact on the stability of octahedral sites. Therefore, OSPE values vary between 0 Dq and 0.845 Dq for different elements. The higher the OSPE value, the greater the degree of inversion, and the higher the quality factor ( Q × f ). The dielectric constant ( ε r ) and temperature coefficient of resonant frequency ( τ f ) of Mg 0.95 X 0.05 Al 2 O 4 ceramics changes as a function of the ionic polarizability and B -site bond valence. Mg 0.95 Ni 0.05 Al 2 O 4 with a higher OSPE (8.45 Dq ) and degree of inversion of A/B sites (λ = 0.221), has the better set of microwave dielectric properties ( ε r = 8.39, Q × f = 78,338 GHz, τ f = −66.8 ppm/°C). The adjustment of stability energy of octahedral sites is favorable to improve the microwave dielectric properties of MgAl 2 O 4 spinel.
研究领域:
材料科学
·
陶瓷
·
介电材料
·
固态化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Hongwei Yang,Meijun Guo,Fang Xu,Yulong Liao,Yong Ren,Guixiang Liu,Honglan Lai,Bochengwen Sun,Bo Dai
In this study, nanoparticles of LiZn ferrite (nano-LiZn, 0.0–10.0 wt. %) fabricated via the sol-gel method and V 2 O 5 particles were added into a Li 0.43 Zn 0.27 Ti 0.13 Fe 2.17 O 4 (LiZnTi) ferrite to realize low temperature sintering . The effects of the nano-LiZn ferrite addition on the crystalline phase formation, microstructure, and magnetic properties of LiZnTi ferrite were systematically investigated. X-ray diffraction results reveal that the LiZnTi ferrite doped with nano-LiZn and V 2 O 5 additives present a pure spinel structure, which can be explained by liquid phase of V 2 O 5 and spinel structure of nano-LiZn, as revealed by high-resolution transmission electron microscopy and selected area electron diffraction data. Scanning electron microscopy images show that the addition of nano-LiZn leads to a change in the microstructure, with the grains becoming uniform and dense. Additionally, the variation in the saturation magnetization ( M s ) depends on the LiZn content. In particular, M s increases with increasing LiZn content from 2.0 to 10.0 wt. %. Finally, the LiZnTi ferrite doped 4.0 wt. % nano-LiZn and 0.60 wt. % V 2 O 5 possesses a narrow ferromagnetic resonance linewidth of 197 Oe, a reduced coercivity of 192.6 A/m, and an improved bulk density of 4.73 g/cm 3 .
研究领域:
材料科学
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磁性材料
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陶瓷
·
电磁学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Chao Xu,Xuetong Zhao,Lulu Ren,Jianjie Sun,Lijun Yang,Jing Guo,Ruijin Liao
Highly dense CaCu 3 Ti 4 O 12 (CCTO) ceramics co-doped by ZnO and Al 2 O 3 were synthesized by spark plasma sintering (SPS) at 750 °C for 10 min, and then annealed at 1000 °C for 3 h. The homogeneous microstructures were achieved, and the grain size was suppressed to around 2 μm. Dramatically enhanced electrical properties of CCTO ceramics were obtained when 1 mol% ZnO and Al 2 O 3 were co-doped. The breakdown field was improved to 12.13 kV/cm and the nonlinear coefficient was increased to 6.59, accompanying with a low dielectric loss of 0.02 at around 1 kHz, which were ascribed to the elevation of Schottky barrier height from 0.54 eV to 0.80 eV. Comparing with the pure CCTO sample, the activation energy of grain boundary obtained from the impedance spectra increases from 0.64 eV to 0.92 eV. Additionally, the grain and grain boundary resistance were also discussed based on the Cole-Cole plot, from which the grain boundary resistance was found to be increased significantly from 3.8 × 10 5 Ω to 4.0 × 10 6 Ω after co-doping.
研究领域:
材料科学
·
陶瓷
·
电气工程
·
固体物理
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2020
·
IF 2.779
Jianping Huang,Xiukuang Zhang,Tiehui Fang,Binbin Liu,Tiezheng Lv,Zuli Mao
Lanthanum-cerium oxides have promising potential for high temperature thermal protection . In this paper, lanthanum-cerium oxides with different La contents were synthesized by hydrothermal method and subsequent thermal treatment. The effect of La content on the microstructure and infrared emissivity were thoroughly studied. The infrared emissivity in 2.5–10 μm wavelength band of the samples increases with the doping of La content. Compared with pure CeO 2 , the emissivity of La 2 Ce 2 O 7 increased 32.4% at 600 °C and 16.9% at 800 °C, respectively. The emissivity enhancement is attributed to the free carrier absorption and lattice absorption in wavelength band 2.5–10 μm. The enhanced emissivity is of great significance for the radiation thermal control in high temperature.
研究领域:
材料科学
·
陶瓷
·
热工工程
·
红外技术
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2016
·
IF 2.183
Song Hu,Xianpeng Qin,Xiaoxia Liu,Guohong Zhou,Chunhua Lu,Shiwei Wang,Zhongzi Xu
Highly transparent Er 3 Al 5 O 12 (ErAG) ceramic was fabricated by a solid-state reactive sintering method under vacuum. The optical property , microstructure and up-conversion luminescence of the ErAG ceramic were investigated. For the 3 mm thick sample, the in-line transmittance at the wavelength of 3000 nm and 425 nm were about 84% and 81%, respectively, which was very close to the theoretical transmittance of the Er 3 Al 5 O 12 single crystal . Micrograph of the ErAG transparent ceramic exhibited a pore-free structure and the density of the ceramic was measured to be 6.38 g/cm 3 . Average grain size of the ceramic was about 9 μm. When pumped by a 980 nm laser diodes (LD), strong green and red emission in the ErAG ceramic was observed from the photoluminescence (PL) spectrum. The luminescent properties of the ceramic under the excitation of LD with various pumping power were investigated.
研究领域:
材料科学
·
光学材料
·
陶瓷
·
发光学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 28
·期 2
·1620-1623
·
IF 1.798
Zhang Shuai,Li Lingxia,Lv Xiaosong
The Mg 3 (PO 4 ) 2 ceramics were prepared by using the conventional solid-state reaction method. And the samples sintered at 1025 °C showed high relative density with 96.51 %. The crystal structure and dielectric properties of Mg 3 (PO 4 ) 2 ceramics were investigated. Optimized dielectric properties tested at 1 MHz were obtained in Mg 3 (PO 4 ) 2 ceramic sintered at 1025 °C for 2 h (ε r ~ 5.9, tanδ ~ 0.0015 and τ ε ~ 40 ppm/°C). Meanwhile, Mg 3 (PO 4 ) 2 ceramic showed the chemical compatibility with Ag electrodes, which can be a promising candidate for multilayer components applications in high frequency.
研究领域:
材料科学
·
陶瓷
·
介电材料
·
电子材料
✓ 已验证
DOI
高影响因子
POWDER TECHNOLOGY
·
2017
·
IF 2.942
Xiaoqing Kan,Jun Ding,Hongxi Zhu,Chengji Deng,Chao Yu
We investigate a new method for the synthesis of nanoscale titanium nitride via a molten-salt-mediated reduction route; the reaction was carried out at a temperature of 600–1100 °C for 1–7 h in a nitrogen atmosphere using TiO 2 and Mg powders as starting materials. The effects of the TiO 2 /Mg mole ratio, reaction temperature, reaction time and salts on the formation of TiN were studied. The phase composition, morphological structure, and particle size of the TiN powder were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy , and a Brunauer–Emmett–Teller specific-surface-area analysis. The results showed that the as-synthesized TiN crystals were approximately 5–30 nm in size and the specific surface areas of the TiN particles were 76.47–93.09 m 2 /g, higher than the 9.83 m 2 /g of the raw TiO 2 . A possible reaction mechanism for the formation of TiN powder in molten salt is proposed.
研究领域:
材料科学
·
纳米技术
·
无机化学
·
陶瓷
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·Vol. 47
·期 18
·26310-26318
·
IF 4.527
Hao Liu,Chuang Jie,Zhongzhuang Zhang,Zhoufu Wang,Yan Ma,Xitang Wang,Honghong Wang,Ke Wu,Guoqiang Zheng
A study of magnesia refractories containing glucose, citric acid, and metallic Al and their influences on structure, mechanical strength , and thermal shock resistance , is presented. Combined with thermodynamic calculation, microstructure, and properties analysis, the results show that formation of gluconates and citrates from the introduced glucose and citric acid enhanced the bonding of raw materials and the curing strength of samples. The pyrolysis of gluconates and citrates, and the oxidation and nitridation of metallic Al had significant effects on the microstructural evolution of magnesia refractories after high temperature treatments, mainly AlN and MgAl 2 O 4 whiskers in pores and particle gaps. The formation and development of whiskers give rise to samples improved toughness and thermal shock resistance. Increasing the metallic Al content from 0 wt% to 2 wt% enhanced the fracture surface energy of samples heat treated at 1400 °C from 82.22 kJ/m 2 to 119.75 kJ/m 2 . Meanwhile, after three thermal-shock cycles, the residual strength ratios of heat treated samples were elevated from 52.8% to 67.9%. On the basis of influences of phase transformation on the structure and properties of samples at different temperatures, considering the structural compactness and ability to withstand external stress for magnesia refractories used in metallurgical field, it is suggested that when glucose and citric acid are used as binders, the addition of metallic Al should be less than 3 wt%.
研究领域:
材料科学
·
陶瓷
·
耐火材料
·
热力学
·
微观结构分析
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·Vol. 45
·期 1
·116855
·
IF 5.8
Jintao Zhang,Shuai Xu,Chunmei Wen,Jiale Huang,Jiaqi Li,Zhongzheng Wu,Renda Wang,Fangfang Ge,Gaowei Zhang,Zhongqiang Fang,Jun Li,Tongmin Zhang,Xuan Meng,Bingsheng Li
High-entropy carbide ceramics (Ti 0.25 Zr 0.25 Nb 0.25 Ta 0.25 )C with a single-phase rock-salt structure were prepared by hot-pressed sintering. These ceramics were irradiated with 500 keV He 2+ ions to fluences of 5 × 10 16 ions·cm −2 and 1 × 10 17 ions·cm −2 at room temperature to 700 °C. The investigation into irradiation-induced lattice swelling was conducted using grazing incident X-ray diffraction, while microstructure evolution was characterized through transmission electron microscopy . Lattice expansion induced by the He ion irradiation was identified, which highly depends on the irradiation temperature and fluence. Notably, the lattice expansion diminishes with rising irradiation temperature primarily as a result of the dynamic annealing effect . Nano-sized He bubbles , with an average diameter of less than 1 nm were uniformly dispersed within the grain interior. Notably, He bubble nucleation does not exhibit a preference for grain boundaries at 700 °C irradiation. Following He ion irradiation at 350 °C and 700 °C, dislocation loops of 1/3<111> and 1/2<110> with sizes in the ranges of several nanometers were observed. The present study provides insights into high-entropy carbide ceramics with potential applications in the field of nuclear energy.
研究领域:
材料科学
·
核材料
·
辐照损伤
·
陶瓷
·
微观结构表征
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2012
·Vol. 39
·期 3
·2267-2274
·
IF 1.751
Rujie He,Ping Hu,Xinghong Zhang,Wenbo Han,Chuncheng Wei,Yang Hou
PEI was used as dispersant for ZrB 2 and SiC powders in water. The dispersion behavior of ZrB 2 and SiC in water was studied by zeta potential measurements , particle size distribution measurements and interparticle interaction calculations. Well-dispersed ZrB 2 and SiC aqueous suspensions were obtained using 0.6 wt% PEI at pH 6. The rheological behavior of ZrB 2 –SiC aqueous suspensions was also investigated. Finally, a high solid loading (52 vol%), low viscosity (980 mPa s at 100 s −1 ) ZrB 2 –SiC aqueous suspension was successfully prepared.
研究领域:
材料科学
·
陶瓷
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
MATERIALS & DESIGN
·
2016
·
IF 3.997
Shugang Chen,Yanzi Gou,Hao Wang,Ke Jian,Jun Wang
In order to prepare ZrC-ZrB 2 nanocomposite ceramics with high temperature stability from single-source precursors, the reactions of ZrCl 4 , allyl amine, allyl-MgCl and borane were employed to synthesize suitable precursors. The meliorated ZrNCB precursor had favorable solubility and higher ceramic yield (68.8 wt%), which was then transformed to ZrC-ZrB 2 ceramics at different temperatures. The main phase of the ceramics was amorphous at 1000 °C. As the temperature increased, the amorphous phases started to crystallize, resulting in the appearance of ZrC and ZrB 2 peaks. The content of ZrC and ZrB 2 phases was relatively high in the nanocomposite ceramics at 1600 °C (over 80 wt%). The ZrC-ZrB 2 nanocomposite ceramics showed good high temperature stability up to 2000 °C. Oxidation test indicated that an oxide layer was formed on the ceramic surface at 1700 °C under air to prevent further oxidation of the ceramics. With excellent high temperature and oxidation resistances , the ZrC-ZrB 2 nanocomposite ceramics have potential application for advanced rocket engines and nuclear industry.
研究领域:
材料科学
·
陶瓷
·
高温材料
·
纳米复合材料
·
航空航天工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）