Materialia
·
2018
·
IF 0
Peng Wu,Mingyu Hu,Lin Chen,Wei Chen,Xiaoyu Chong,Hui Gu,Jing Feng
A series of ceramics of (Y 1-x Dy x )TaO 4 monoclinic phases (space group: I2 (5)) are prepared by the solid-state reaction method. The high-resolution transmission electron microscopy (HRTEM) suggest the (Y 1-x Dy x )TaO 4 ceramics possess ferroelastic domain, which is derived from reversible second-order ferroelastic transformation between the high-temperature tetragonal (t) and low-temperature monoclinic (m) phase. Similar to metastable tetragonal YSZ ceramics, the ferroelastic toughening mechanism may exist in m-phase (Y 1-x Dy x )TaO 4 ceramics through the shift or reorientation of ferroelastic domain under the stress field of a crack. The energy dispersive spectroscopy reveals that the elements of Y and Dy are inhomogeneous in the grain of (Y 1-x Dy x )TaO 4 ceramics, which breaks down the relationship of concave parabola between thermal conductivity and composition parameter (x). Moreover, the thermal conductivities (1.7–2.0 W/m/k at 900 ̊C) and thermal expansion coefficients (TECs) (10–11 × 10 −6 K −1 ) of (Y 1-x Dy x )TaO 4 ceramics are comparable to that of YSZ (yttria-stabilized zirconia). In view of the low thermal conductivity, high thermal expansion coefficients, good high-temperature phase stability and ferroelastic transformation, the (Y 1-x Dy x )TaO 4 ceramics show great potentials in the application of high-temperature thermal insulator materials, particularly as thermal barrier coatings .
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
CRYSTENGCOMM
·
2018
·Vol. 20
·期 48
·7773-7781
·
IF 3.304
Rui Yuan,Xi-Xi Xie,Li-Xian Zheng,Li-Li Yu,Jian-Feng Hu,Hai-Ming Qin,Zhi-Jun Zhang,Jing-Tai Zhao
By exploring the optimal reaction temperature and the ratio of Na2SO4 to the precursor, highly symmetrical rhombic dodecahedral yttrium aluminum garnet (Y3Al5O12, YAG) microcrystals with a good dispersity were successfully prepared using improved hydrothermal methods. YAG microcrystals exhibit well-developed crystal faces, high crystallinity and a controllable crystal size, from hundreds of nanometers to approximately 4 μm. The morphology and crystal size of the YAG microcrystals can be controlled by changing the reaction temperature and the ratio of Na2SO4 to the precursor. After analysis using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and energy dispersive spectrometry (EDS), the growth mechanism of the YAG crystals was studied in detail. Cerium doped YAG (YAG:Ce3+) microcrystals exhibit an intense broad band emission at approximately 523 nm. Considering the high crystallinity, controllable size and strong emission of YAG microcrystals, one has reason to assume that they could have wide applications in many areas.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Man Wang,Lichun Cheng,Lei Huang,Fengxin Ye,Qingrong Yao,Zhao Lu,Huaiying Zhou,Haiying Qi
Yttrium perovskite ferrite has a stable and symmetrical crystal structure and a simple preparation route. However, it exhibits poor absorption performance at 17–18 GHz. Several studies in the past have reported on the formation of mixed-valence states induced by the addition of monovalent K ions . In this study, YFeO 3 was synthesized by doping with monovalent K via the sol-gel auto combustion method. This greatly optimized the wave-absorbing properties and effective bandwidth of YFeO 3 . The influence of different K additions on the absorption properties of the materials was also studied. All the hybrid composites showed excellent absorbing properties, with Y 0.8 K 0.2 FeO 3 having an effective bandwidth of 4.88 GHz at a simulated thickness of 2.0 mm, Furthermore, the reflection loss (RL) value of Y 0.7 K 0.3 FeO 3 reached − 30.56 dB at 15.44 GHz (effective bandwidth up to 4.72 GHz) corresponding to the thickness of only 1.6 mm. This demonstrates that this broadband effect is greater than other similar materials. Moreover, the as-prepared samples completely covered the X and Ku band at only 2.2 mm, and the maximum effective bandwidth reached 5.28 GHz at 2.0 mm. The excellent wave absorption and frequency broadening effects were due to the various loss mechanisms and improved impedance matching characteristics caused by doping.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2023
·Vol. 13
·期 2
·252
·
IF 3.4
Yunzhang Li,Meng Zhou,Yi Zhang,Hanjing Zhu,Xianhua Zheng,Shengli Liang,Shunlong Tang,Baohong Tian,Yong Liu,Xu Li,Alex A. Volinsky,Chenglin Zheng
With the massive penetration of electronics into human life, higher demands are placed on electrical contacts. Among them, the lifetime of electrical contacts and safety are the most concerning. In this research, Al2O3-Cu/25Mo5Ta and 0.5Y2O3/Al2O3-Cu/25Mo5Ta composites were prepared by using ball milling and powder metallurgy methods. The two composites were subjected to 10,000 contact opening and closing electrical contact experiments and the arc duration and arc energy were analyzed. The results show that the addition of Y2O3has a slight effect on the mechanical properties of the Al2O3-Cu/25Mo5Ta composites but has a significant effect on the electrical contact performance. Y2O3can reduce the mass loss of the electrical contacts during the electrical contact process, which prolongs their service life. The addition of Y2O3decreased the average arc duration and arc energy of the electrical contact material by 21.53% and 18.02%, respectively, under the experimental conditions of DC 30 V, 10 A. TEM results showed that nanoscale YTaO4with excellent thermal stability was generated during the sintering process, which has a positive effect on the electrical contact performance of the composites.Keywords:copper matrix composites;electrical contact;arc erosion behavior;yttrium tantalate
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Kaichen Qian,Jiantai Fan,Zongyun Shen,Lulu Zhang,Xianglong Fan,Tao Feng,Weiwen Zhou,Minghui Feng,Benxue Jiang,Long Zhang
A citrate-nitrate combustion method was applied to synthesize fine composite Gd 2-x Y x O 3 -MgO (x = 0, 0.02, 0.2, 0.3, 0.4, 0.6) nanopowders . Y 2 O 3 substitution inhibited Gd 2 O 3 phase transition from cubic structure to monoclinic structure during sintering, thereby stabilizing its cubic structure to room temperature. This approach led to nanocomposite ceramics with a grain size of about 190 nm and increased the transmittance to 85% over the 3–5 μm wavelength range when x = 0.3. However, the addition of Y 2 O 3 weakened the mechanic properties of the nanocomposite ceramics.
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
ADVANCED FUNCTIONAL MATERIALS
·
2023
·Vol. 34
·期 3
·2306176
·
IF 19
Qingren Zhang,Tongtong Liu,Hengyu Guo,Yanan Chen,Yajing Di,Zhengping Zhang,Feng Wang
Pyrochlore ruthenates are highlighted as candidates to replace iridium oxide as oxygen evolution reaction (OER) electrocatalyst, but their designable geometric configurations and composition modulations are hampered by the high-temperature (≈1100 °C) and long-time calcination (more than 12 h), which further decreases the technical and economic feasibility. In this work, an energy- and time-saving approach is proposed to prepare pyrochlore yttrium ruthenate at a much lower calcination temperature (600 °C) and shorter calcination time (6 h) just by inducing A-site substitutions of lead ions (YPRO). The local microstrain derived from Pb provides the surficial compression and extra driving force to overcome the strain energy of phase-transition resistances and the obtained low-temperature YPRO exhibits enriched pores, deficient geometries, shortened Ru─O bond, and enlarged Ru─O─Ru bond angle, which further modify the electronic structure, involving of the rearranged band alignment and the eliminated bandgap. The regulated morphologic, geometric, and electronic structures in YPRO synergically boost the electrocatalytic OER performance (4.8-fold and 30.0-fold enhancements compared with pyrochlore yttrium ruthenate and commercial iridium dioxide (IrO 2 ), respectively) in universal pH conditions. This substitution-induced strain engineering on phase transition should also be effective for other high-temperature materials and trigger their diverse intriguing properties.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Lihua Guo,Guoqiang Wang,Feng Zhang,Linyuan Lu,Bin Luo,Hongtao Huang,Jun Lin
The fissile fuel loss in tungsten (W) based ceramic-metal (Cermet) element used in nuclear thermal propulsion is of great importance. In this study, the W-Y 2 O 3 composite matrix was manufactured tentatively by Spark Plasma Sintering (SPS) to relieve the fuel loss. Performance evaluation of hydrogen (H 2 ) permeation and diffusion behaviors in the matrix was carried out by a gas permeation device. The results indicate that the diffusion coefficient of H 2 in the pure W matrix is nearly 10 times larger than that in the W-Y 2 O 3 matrix at a test temperature of 823 K. Based on the results, a careful investigation of the fuel loss mechanism of the Y 2 O 3 dispersed W matrix was performed. SEM and TEM showed that the fine Y 2 O 3 particles are distributed along grain boundaries of the W ternary-phase and present a distinct transition region of about 10 nm between the Y 2 O 3 and W phases. In particular, the crystallographic orientation relationship suggests that a semi-coherent structure is formed at the W/Y 2 O 3 phase interface : (0 1 −1) W || (1 0 −1) Y 2 O 3 and [0 1 1] W || [1 1 1] Y 2 O 3 . This semi-coherent structure is favorable for binding the two phases together tightly, thus hindering the inward diffusion of H 2 greatly. Moreover, the improved density and refined size of the W grains are achieved. Therefore, there is no doubt that the dispersion of Y 2 O 3 is beneficial for lowering the H 2 diffusion rate in the W matrix and thus reducing the fuel loss effectively. This work furthers our understanding of the key role of Y 2 O 3 in the W matrix used in nuclear thermal propulsion.
研究领域:
材料科学
·
核能工程
✓ 已验证
产品关联
DOI
高影响因子
Energy & Environmental Science
·
2024
·
IF 32.4
Yunlong Deng,Jian Gao,Ming Wang,Jinxiang Deng,Yicheng Zhou,Wei Sun
Effective lithium (Li) metal alloying in adjusting its crystallization process offers a reliable approach to refine the grain size and alter the grain boundary composition, consequently enhancing its stripping/plating behavior. Key requisites for the alloying composition include a high melting point, which aids in heterogeneous nucleation of lithium metal, and a robust adsorption of lithium ions. Using the Bramfitt equation as a basis, this study demonstrates that Al2Yb facilitates heterogeneous nucleation with Li, leading to grain refinement and an increase in active sites. Al2Yb's superior adsorption energy compared to Li is noteworthy, enabling the dense deposition of lithium ions on the electrode surface, forming a flat surface that effectively suppresses side reactions. Consequently, the Li–3Al–1Yb electrode exhibits exceptional material structural stability, electrochemical cycling stability, and rate performance in various cell configurations, including Li–Li symmetrical coin cells, Li‖NCM811 cells, and pouch cells. This investigation not only offers insights into addressing challenges related to dendrite growth in metal lithium but also contributes to the improvement of both electrochemical and mechanical properties.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Symmetry-Basel
·
2025
·Vol. 17
·期 2
·224
·
IF 2.2
Yaohui Xu,Yong Li,Liangjuan Gao,Zhao Ding
CeO2has a potential application in the purification of organic dye wastewater because of the abundant oxygen vacancy (VO) defects in its crystals. In this study, a cubic CeO2microsphere with layered interleaved symmetrical 3D flower-like morphology was synthesized, and its adsorption capacity for acid orange 7 (AO7) was further enhanced by Y doping. The impact of varying amounts of Y ions on the phase composition, lattice parameters, and morphology of the product was investigated, revealing that 4 mol.% was determined as the doping level limit of Y ions in CeO2crystals. XPS, Raman, and H2−TPR techniques were employed to compare surface species changes before and after 4 mol.% Y doping in the CeO2crystals, including O−Ce(III), O−Ce(IV), O−Y(III), and VOcorrelation, yielding a rough quantitative assessment of these species. The 4 mol.% Y-doped CeO2(2.0 g/L) demonstrated the highest removal rate for 20 mg/L of AO7 dye within just 20 min to reach adsorption–desorption equilibrium, half the time required by undoped CeO2, achieving an impressive adsorption rate of 94.6%, compared to only 69.5% for undoped CeO2at 20 min. The adsorption capacity of undoped CeO2was enhanced by 19.05% through the doping of 4 mol.% Y, achieving a value of 16.56 mg/L. The feasibility of enhancing the adsorption capacity of CeO2by Y doping provides a reference for the application of CeO2and other metal oxides.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Pei Ren,Xingan Wang,Mu Zhang,Xudong Sun
Yttrium oxide is an ideal choice for titanium aluminum alloy melting and casting, its wider use is hindered by sintering challenges and low thermal shock resistance . To address this, we propose a gel casting method for calcium oxide-doped yttrium oxide production. We pretreated yttrium oxide with phosphoric acid to prevented hydrolysis and adjusted the isoelectric point of yttrium oxide to match calcium carbonate's. Anions from calcium carbonate increased slurry solid content (up to 58 vol%) while maintaining low viscosity (57.78 mPa·s at 40 s −1 shear rate). After sintering at 1650 °C for 2 h, the material showed a flexural strength of 78 MPa, with a 90% retention rate after thermal shock test. The introduction of calcium oxide induced lattice distortion, improving mechanical properties by aiding sintering and grain boundary diffusion. XPS and STEM analysis confirmed random replacement of Y 3+ by Ca 2+ at the C 2 position with 1 wt% doping.
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
FUEL
·
2024
·
IF 6.7
Wenxia Wang,Yuliang Zhu,Yingchao Hu
High-temperature CO 2 capture based on Li 4 SiO 4 sorbents has been well recognized as an effective approach to mitigate the global warming issues. However, the relatively low sorption performance is one of the biggest challenges for the practical application. In the current investigation, Na- and Y-based dopants have been employed to enhance cyclic CO 2 sorption performance of Li 4 SiO 4 sorbents. Various physicochemical properties and cyclic CO 2 sorption performance of the prepared sorbents have been systematically studied. The results indicated that Na 2 CO 3 and Y 2 O 3 codoped Li 4 SiO 4 sorbent (Li 4 SiO 4 -10Na-15Y) exhibited excellent cyclic CO 2 capture performance with stable capacity of >0.27 g CO 2 /g sorbent (corresponding to the carbonation conversion of ∼96 %) during 15 sorption/desorption cycles. Even under lower CO 2 concentration and longer cycles, satisfying conversions of 85 % could be kept in the cyclic tests for the codoped Li 4 SiO 4 sorbent. In addition, the materials also showed high heat storage density of 557.8 kJ/kg and the performance was stabilized in the multicycle energy storage/release tests. The characterization results showed that the introduction of Y-based dopants induced triple positive effects for Li 4 SiO 4 including porosity creation, sintering-resistant ability, and producing Li 4 SiO 4 lattice defects. As a result, the enhanced specific surface area and reduced diffusion resistance were achieved and, thus, the CO 2 sorption performance including sorption capacity (heat storage density) and cyclic stability was obviously improved.
研究领域:
材料科学
·
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2018
·
IF 2.873
Jinbo Zhao,Lili Wu,Chuanjiang Zhang,Tingxi Li,Qinglong Jiang,Feng Wang,Ping Zhao,Jong Eun Ryu,Zhanhu Guo
Petal-like Yb 3+ -Tm 3+ codoped Y 7 O 6 F 9 microparticles were achieved via ionic liquid-assisted (IL) hydrothermal process. The emission efficiency of Y 7 O 6 F 9 :Yb 3+ /Tm 3+ powders is much stronger than that of Y 2 O 3 :Yb 3+ /Tm 3+ sample. Under excitation at 980 nm with an unfocused laser beam under weak pump density of ∼0.1 W/cm 2 (pump power 10 mW), the UC emission of the sample can been seen clearly. Four emission bands at 477, 540, 647 and 692 nm are observed and correspond to the 1 G 4 state to 3 H 6 state, 1 D 2 state to 3 H 5 state, 1 G 4 sate to 3 F 4 state, and 3 F 3 state to 3 H 6 state transition of Tm 3+ ions. The enhanced UC emission is related to high crystallinity and lower effective phonon energy of oxyfluorides. The ionic liquid (IL) of [BMIM][BF 4 ] is used both as the reaction medium and the source of F − .
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）