Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 25
·9236-9246
·
IF 5.7
Bo You,Bin Lu,Dazhen Wu,Ruijie Pei
MgO was found to be a good sintering aid for densification of several types of ceramics; however, the previous reports seldom provided persuasive evidence to support their proposed functional mechanism. In the present work, we successfully fabricated polycrystalline transparent In2O3 semiconductor ceramics using MgO as an additive and offered vital insight into the additive roles in sintering behavior and optical properties, which are conducive to mastering the microstructure evolution principle and interaction function mechanism. The oxygen defect and solute drag mechanisms have combined effects on the sintering of MgO-doped In2O3 ceramics. Additionally, MgO also helps to improve the thermal stability. At the optimized MgO content of 0.5 at%, the In2O3 ceramic sintered at 1600 °C under an oxygen atmosphere achieves an in-line transmittance of 63.0% at 633 nm (∼83% of the theoretical transmittance of a perfect In2O3 single crystal) with a fine average grain size of ∼9.7 μm. Upon deep UV excitation, the transparent In2O3 semiconductors exhibit broad spectral bands covering from the near-UV to the entire visible region, where the dominant ∼493 nm cyan light derives from the deep-level defect emission. The MgO dopants enhance the photoluminescence intensity and prolong the deep-level fluorescence lifetime. The cathodoluminescence spectra show broad orange emission, with the emission centers located at 626 and 613 nm for the intra-grain and grain-boundary regions, respectively. The integral intensity of cathodoluminescence increases as the acceleration voltage increases, while the intensity in the grain interior is much higher than that on the grain boundary at each voltage.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Shuo Yan,Yuhong Chen,Ziqiang Yin,Binwei Huang,Quanxing Ren,Tihao Cao,Xuxin Ping,Ruibin Liu,Zhengren Huang,Qing Huang,Yinsheng Li
SiC ceramics were fabricated by spark plasma sintering of β-SiC powder with various rare-earth (RE = La, Gd, Yb, Sc) oxides and magnesia additives. The phase compositions, microstructures, lattice oxygen contents, and thermal conductivities were systematically investigated. A decrease in the cationic radius of rare-earth element resulted in an increased cationic field strength. This enhanced attraction to oxygen anion led to higher viscosity and improved high-temperature stability of the intergranular RE-Mg-Si-O liquid phase. After sintering at 1850°C, influenced by liquid-phase viscosity, the degree of β→α phase transformation in SiC and the grain size decreased with decreasing cationic radius of rare-earth element. After sintering at 2050°C, the liquid-phase viscosity significantly decreased, but volatilization became pronounced. The extent of β→α phase transformation and the grain size were affected by both liquid-phase viscosity and volatility. Larger grain size and higher affinity of rare-earth cations for oxygen anions contributed to reduce lattice oxygen content. The thermal conductivities of the SiC ceramics ranged from 192 to 229 W/mK. Notably, the SiC ceramic with Yb 2 O 3 -MgO additives exhibited the largest grain size, the lowest lattice oxygen content, and the elimination of β/α heterophase boundaries, thereby achieving the highest thermal conductivity of 229 W/mK.
研究领域:
材料科学
·
热传导工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yongzhi Luo,Bin Wang,Xi Zhang,Bin Kang,Jianguo Deng,Shengquan Yu
Nd:Y 2 O 3 transparent ceramics were fabricated by vacuum pre-sintering and post-hot isostatic pressing with ZrO 2 and MgO as sintering additives. It was found that binary additives not only promoted the densification of Y 2 O 3 ceramics, but also decreased the pre-sintering temperature by at least 150 °C compared with the single addition of ZrO 2 . The best quality sample with 1 at.% ZrO 2 and 0.06 at.% MgO was pre-sintered at 1550 °C and post-HIPed at 1500 °C. The average grain size was approximately 0.96 μm, and the in-line transmittance reached 75.9 % at 400 nm and 81.4 % at 1000 nm. The ceramic also exhibits good optical homogeneity, which is evaluated by the interference stripes with the PV and RMS values of 385.8 nm and 21.3 nm, respectively. Continuous wave laser operation of the sample was demonstrated, and a maximum output power of 1.73 W at 1080.4 nm was achieved with a slope efficiency of 11.3 %.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Hongyu Liang,Shijing Zou,Manqiang Liu,Tianqiang Yin,Xiaojie Xia,Xijun Hua,Yonghong Fu,Yongfeng Bu
The low concentration of water-based lubricants and the high chemical inertness of the additives involved are often regarded as basic norms in the design of liquid lubricants. Herein, a novel liquid superlubricant of an aqueous solution containing a relatively high concentration of salt, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), is reported for the first time, and the superlubricity stability and load-bearing capacity of the optimized system (MgO0.10/LiTFSI10) are effectively strengthened by the addition of only trace (0.10 wt %) water–chemically active MgO additives. It demonstrates higher applicable loads, lower COF (∼0.004), and stability relative to the base solution. Only a trace amount of MgO additive is needed for the superlubricity, which makes up for the cost and environmental deficiencies of LiTFSI10. The weak interaction region between free water and the outer-layer water of Li+ hydration shells becomes a possible ultralow shear resistance sliding interface; the Mg(OH)2 layer, generated by the reaction of MgO with water, further creates additional weakly interacting interfaces, leading to the formation of an asymmetric contact between the clusters/particles within the hydrodynamic film by moderating the competition between interfacial water and free water, thus achieving high load-bearing macroscopic superlubricity. This study deepens the contribution of electrolyte concentration to ionic hydration and superlubricity due to the low shear slip layer formed by interfacial water competition with water-activated solid additives, providing new insights into the next generation of high load-bearing water-based liquid superlubricity systems.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Canglong Wang,Zhaocang Meng,Jianke Tian,Yiwen Liu,Yafeng Shu,Haibo Wu,Lei Yang
Given the wide prospects for SiC ceramic with high thermal conductivity, high-throughput screening of SiC containing BeO-Y 2 O 3 -Al 2 O 3 -MgO additives has been implemented by the experimental and multiscale simulation investigation. About 16 groups of SiC prepared by SPS are composed of 4H-SiC, 6H-SiC, 3C-SiC, BeO and yttrium aluminum garnet phases, and exhibit equiaxed and columnar microstructures. It was verified by the density functional theory simulation that these dopants (Be, O, Mg, Al and Y) can migrate spontaneously towards the Σ13 (150) [001] GB. The ceramics with thermal conductivity higher than 120 W/(m·K) were screened out. Especially, the annealed SiC with 5%BeO-10 % additive exhibits the maximum thermal conductivity of 206.5 W/(m·K). The Vickers hardness about 16.89 GPa can be predicted by the macro finite element model simulation, which is accorded with the experimental result. This work provides an economically feasible project for the large-scale production of SiC ceramics with high thermal conductivity.
研究领域:
材料科学
·
计算材料学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Ge Yang,Xi Yan,Yan Chen,Xiao-Jing Guo,Wan-Zhong Lang,Ya-Jun Guo
In recent years, Ga-based catalysts attract much attention in propane dehydrogenation (PDH) reaction due to environmental friendliness and low cost. Nevertheless, it is still challenging to obtain high selectivity of propylene under harsh reaction conditions. In this work, the supported catalysts (Ga- x Mg/ZSM-5) were prepared with the sequential impregnation method and applied in the PDH reaction. The results show that MgO as an additive reduces the acidity of the catalysts, promotes the dispersion of Ga 2 O 3 and improves the selectivity of propylene. As a result, the average particle size of the Ga/ZSM-5 catalyst is larger (4.5 nm), and the initial propylene selectivity is only 71.0 %. In contrast, the optimal Ga-0.7Mg/ZSM-5 catalyst shows the smallest particle size (2.4 nm) and the highest propylene selectivity of 90.8 %. In comparison with the previous GaO x catalysts in literatures, the Ga-0.7Mg/ZSM-5 catalyst exhibits a superior production rate of propylene ( r C 3 H 6 ) based on either catalyst weight or Ga 2 O 3 weight.
研究领域:
催化化学
·
材料科学
✓ 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）