SURFACE & COATINGS TECHNOLOGY
·
2021
·
IF 4.158
Wenqi Yang,Fuxing Ye
The development of YSZ TBCs has been limited by the CMAS corrosion and thermophysical characteristics. The Ytterbium Tantalate (YbTaO 4 ) ceramic was selected in this study to evaluate its potential to replace traditional YSZ. The thermal and mechanical properties of YbTaO 4 show great advantages over YSZ, especially the hardness (191.3 ± 7.6 Hv 0.3 ). The CMAS hot corrosion results indicate that the maximum thickness of the reaction layer at 1350 °C after 24 h is ~16.8 μm, which is much thinner than that of YSZ. Moreover, the porosity of the reaction layer does not increase significantly compared with the YSZ TBCs. The main product after the reaction is the Ca 2 Ta 2 O 7 phase, and there is no anorthite phase after the reaction, mainly because the formation of the Ca 2 Ta 2 O 7 phase consumes a lot of Ca atoms. In addition, the equilibrium contact angle of YbTaO 4 is higher than that of YSZ, which indicates that the YbTaO 4 possesses worse wettability . In actual conditions, low wettability is conducive to the YbTaO 4 TBCs get rid of the liquid CMAS, which can effectively reduce the corrosion effect of CMAS. Furthermore, the corrosion depth and area of YbTaO 4 causing by residual CMAS are also smaller due to the poor wettability. Based on the above results, YbTaO 4 exhibits excellent potential to replace YSZ in preparing TBCs for the next generation aero engines.
研究领域:
材料科学
·
航空工程
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2024
·
IF 5.5
Yapeng Kong,Longdi Ma,Heng Zhang,Xiwen Chen,Xuemin Liang,Liqiang Wang,Yangyang Fan,Yuran Chen
Aluminum-tantalum powders are emerging as new raw materials for additive manufacturing (AM) technologies, but their preparation in bulk quantities and in powder form via conventional metallurgical methods is challenging. In this study, we report a one-step synthesis of spherical Al 3 Ta powder by direct electrolyzing solid Ta 2 O 5 cathode ( vs . a graphite anode) in molten Na 3 AlF 6 -K 3 AlF 6 -AlF 3 -LiF-Al 2 O 3 . Cyclic voltammetry and constant potential electrolysis techniques were employed to characterize the electrochemical reaction process, along with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) for the structural and morphological analyses. The process involves an initial Ta 2 O 5 electro-deoxygenation process, the subsequent electrodeposition of Al 3+ on the formed Ta particles and an in-situ alloying process. The innovative use of Ta 2 O 5 cathodes with a novel hierarchical porous structure allows for a controlled transformation of cathode particle morphology and facilitates the rapid generation of nanoscale tantalum particles. Al 3+ from the electrolyte is then electrodeposited onto these particles, initiating an in-situ alloying reaction. This is an exothermic process that facilitates the diffusion of aluminum atoms into tantalum, and reduces the interfacial energy promoting the formation of spherical Al 3 Ta particles. Such powders are in demand for AM techniques. The findings may now guide the way to establishing the electrochemical route for the short-process preparation of other high-temperature alloy powders.
研究领域:
材料科学
·
电化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2014
·
IF 2.93
Li Zhang,Yan Song,Jianyong Feng,Tao Fang,Yujiao Zhong,Zhaosheng Li,Zhigang Zou
Lanthanum tantalum oxynitride (LaTaON 2 ) powders were prepared by one-step flux method. LaTaON 2 photoanodes, which are fabricated by using LaTaON 2 powders, are found to exhibit photoelectrochemical activity for overall water splitting . The photocurrent for LaTaON 2 photoelectrodes was ca. 120 μA cm −2 at 1.5 V vs. reversible hydrogen electrode (RHE) in 1 M NaOH aqueous solutions (pH = 13.6) under AM 1.5 G simulated sunlight irradiation (100 mW cm −2 ). The photocurrent of LaTaON 2 photoelectrode from back-side illumination is much larger than that from front-side illumination, suggesting that the photoelectrochemical property is mainly limited by poor continuous electron transport in the bulk. Further efforts to ameliorate the electron transport in the bulk of LaTaON 2 photoelectrodes are expected to significantly improve their photoelectrochemical performance.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2020
·
IF 2.615
Ai-min LIU,Meng-xia GUO,Zi-yang LÜ,Bao-guo ZHANG,Feng-guo LIU,Wen-ju TAO,You-jian YANG,Xian-wei HU,Zhao-wen WANG,Yu-bao LIU,Zhong-ning SHI
To investigate the electrochemical reduction mechanism of Ta(V) in ethylene carbonate and aluminum chloride (EC−AlCl 3 ) solvate ionic liquid, cyclic voltammetry experiments were conducted on a tungsten working electrode. Four reduction peaks were observed in the cyclic voltammogram of the EC−AlCl 3 −TaCl 5 ionic liquid. The reduction peaks at −0.55, −0.72, and −1.12 V (vs Al) were related to the reduction of Ta(V) to tantalum metal by three stages including the formation of Ta(IV) and Ta(III) complex ions. The reduction of Ta(III) to tantalum metal was an irreversible diffusion-controlled reaction with a diffusion coefficient of 3.7×10 −7 cm 2 /s at 323 K, and the diffusion activation energy was 77 kJ/mol. Moreover, the cathode products at 323 K were characterized by scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy. The results showed that tantalum metal and tantalum oxides were obtained by potentiostatic electrodeposition at −0.8 V for 2 h.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2020
·Vol. 40
·期 7
·1940-1948
·
IF 2.161
Li Jia-Xin,Chen Yu-Hong,Bai Zhang-Jun,Zhao Bao-Jun,Jiang Liang,Wu Lan-Er
Ta–W alloys have unique properties but their applications at high temperatures are restricted due to their poor oxidation resistances. The addition of Al and Ti decreases the oxidation rate of the alloy, as Al-contained protective oxide layer could be formed. In this study, ternary and quaternary Ta–W alloys containing Al and Ti were prepared by hot press sintering. The microstructures and oxidation behaviors of the alloys were studied at 1173 K. The results show that the oxidation kinetics of all alloys follows a parabolic law at short oxidation periods. After cyclic oxidation, the kinetics of quaternary alloys still obeys the parabolic law but that of ternary alloy has been changed into linear law kinetics after 8-h oxidation. For ternary alloy, an outer layer with dense and continuous alumina was formed during the initial stage, and phase transformation caused the oxides to peel off. By comparison, the quaternary alloys depicted continuously solid solution of the oxides layer. Overall, Al and Ti played key roles in oxidation degree and affected the oxidation kinetics of ternary and quaternary alloys.
研究领域:
材料科学
·
金属学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 28
·期 4
·3768-3773
·
IF 1.798
Shen Zhengbo,Wang Xiaohui,Li Longtu
Ta-doped 0.90BaTiO 3 –0.10(Bi 0.5 Na 0.5 )TiO 3 ceramics were successfully prepared by conventional solid-state reaction method and studied to satisfy super-broad temperature stability. The effects of Ta 2 O 5 doping on the dielectric properties and microstructures were thoroughly investigated. Ta plays an important role in the formation of core–shell structure because of chemical inhomogeneity, which gives rise to the weak temperature dependence of dielectric properties. The samples with the additon of 1.5 mol% Ta 2 O 5 satisfy the X9R specification, exhibiting an optimum dielectric behavior of ε
r
~ 2100, tanδ ~ 1.6% at room temperature, which is a promising candidate material for X9R MLCC applications.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2017
·Vol. 43
·期 9
·5011-5024
·
IF 1.369
Zhang Nannan,Li Liping,Li Guangshe
Abstract A facile synthetic route for the preparation of highly active tantalum oxide photocatalysts was developed without using any surfactants. The prepared products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectra, thermogravimetric analysis, and Raman, and their activity was evaluated by photocatalytic H 2 evolution under UV–Vis light irradiation (320 < λ < 780 nm). To elucidate the photocatalytic activity, the nitrogen adsorption–desorption isotherms experiment, ultraviolet–visible diffuse reflectance spectra, photoluminescence and steady-state surface photo-voltage measurements were performed. The recyclable photocatalytic properties were also conducted to demonstrate its high stability. Notably, the obtained samples prepared by direct evaporation are amorphous and own a large specific surface area, and furthermore exhibit a far greater photocatalytic performance than commercial Ta 2 O 5 . On the basis of the above experiment results, the enhanced photocatalytic activity of a -Ta
x
O
y
could be ascribed to the efficient separation and migration of photo-generated carriers as well as the higher energy of the conduction band minimum. Therefore, the direct evaporation synthesis opens a door to the facile preparation of highly active amorphous photocatalysts. Graphical Abstract
研究领域:
材料科学
·
能源化学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2017
·
IF 4.233
Xiao Shao,Xiaohong Yin,Junzheng Wang
Cubic perovskite-type and octahedral pyrochlore-type powders of potassium tantalate (KTaO 3 ) were selectively synthesized by a single-step hydrothermal method under different concentrations of potassium hydroxide (KOH). The obtained photocatalysts were characterized by X–ray diffraction (XRD), energy dispersive X-ray spectra (EDS), scanning electron microscopy (SEM), high–resolution transmission electron microscopy (HRTEM), and UV–vis absorption spectra (UV–vis). The photocatalytic activities of the KTaO 3 samples for reduction of carbon dioxide to methanol under UV light irradiation were investigated. The results showed that the KOH concentration played a significant role in determining the phases of the resultant products. Compared with the cubic crystalline structure, the octahedral crystalline structure exhibited the higher photocatalytic activity. In addition, the photocatalytic activities of KTaO 3 were obviously increased when a small amount of nickel oxide (NiO) was loaded as a co-catalyst. The highest rate of methanol formation was 1815 μmol/g/h when 2 wt% of NiO was loaded.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
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
Inorganic Chemistry Frontiers
·
2022
·Vol. 10
·期 4
·1225-1237
·
IF 7.779
Rui Hu,Yan Zhao,Ying Zhang,Xusheng Wang,Guorong Li,Mingxue Deng
The demand for multidimensional stimulus sensing devices that can be used for the real-time monitoring of the equipment status in complex working environments has led to investigations on multifunctional optoelectronic materials. Nevertheless, the exploitation of all-in-one materials with multimode and multicolor luminescence capacities is still immature. Given the abundant transitions in lanthanide ions and the stress-responsive ability of piezoelectric crystals, multi-activator-doped piezoelectric materials are promising candidates for multifunctional detection based on luminescence characteristics. Herein, we report a novel multidimensional stimulus-sensitive material constructed via combining dual luminescence centers (Bi3+/Er3+) with piezoelectric LiTaO3, thus realizing opto-mechano-thermo-responsive luminescence in a single material. Particularly the photoluminescence is allochroic (cyangreen-yellow) under diverse excitation sources (ultraviolet-blue-near infrared radiation). Its mechanoluminescence performance shows a linear relation with the applied load, allowing its application in stress sensing. In addition, the thermally coupled levels of Er3+ dopants endow the LiTaO3 material with temperature sensing capacity relying on the fluorescence intensity ratio. These findings provide a new method for designing optical function materials and integrated optoelectronic devices toward radiative, stress, and temperature sensing applications.
研究领域:
材料科学
·
光学
·
传感器技术
✓ 已验证
DOI
高影响因子
Materials Chemistry Frontiers
·
2021
·Vol. 5
·期 18
·6891-6903
·
IF 6.482
Rui Hu,Ying Zhang,Yan Zhao,Xusheng Wang,Guorong Li,Mingxue Deng
Mechanoluminescence (ML) materials possess the mechano-optical conversion property that can produce luminescence emission upon a mechanical stimulus. This stress-luminescence responsiveness endows ML materials with application potential for optical information display. For the existing ML materials, the consecutive and overlapped trap-depth distribution in ML materials can sustain persistent afterglow noise and hinder the recognition of ML signals continually. In this study, we designed a synergistic strategy that combines defect engineering with microstructure tuning to achieve the high-contrast ML emission of Bi3+ in lithium tantalite. Non-luminous Ga3+ ions are employed as co-dopants to tune the defect trap distribution and microstructure in Bi3+-doped LiTaO3 crystals. The as-prepared Bi3+/Ga3+ codoped LiTaO3 material showed intense high-contrast ML emission with no afterglow interference under an external mechanical stimulus. Its high-contrast ML intensity increased linearly with increasing applied force (>1200 N), showing no threshold force. The composite film combined with LiTaO3:Bi/Ga particles can respond sensitively and notably to multifarious mechanical stimuli by radiating indigo blue ML light, including stretching, bending and friction. These discoveries provide a new research perspective to investigate stimuli-responsive luminophors toward various application requirements especially with optical information storage and display.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
REACTIVE & FUNCTIONAL POLYMERS
·
2024
·
IF 4.5
Xue Liu,Jianguo Deng,Guohong Pu,Zhihua Deng,Lanxiang Ji,Xiaofeng Bai,Quanping Zhang,Yuanlin Zhou
Traditional radiation protection wearable products will inevitably produce a certain degree of mechanical damage during use, leading to breakage or even failure of our wearable products. In this work, we introduce a novel stretchable, self-healing wearable composite, constructed from a double network matrix of Hydrogen-terminated phenyl polysiloxane (HTPP) and Polyborosiloxane (PBS). These composites obtain robustness and elasticity by using phenyl in HTPP as a rigid component and covalent network. In addition, HTPP acts as a scaffold to keep the shape of PBS stable and provide elasticity. Meanwhile, the supramolecular network presented in PBS contributes to high viscoelasticity and improves the self-healing ability to promote rapid autonomous healing. Moreover, tantalum( V ) oxide (Ta 2 O 5 ) as a functional filler enhances the radiation shielding and thermal management performance of the double cross-linked elastomer . This unique combination of thermal management, autonomous self-healing, and mechanical strength , as well as radiation protection, may endow this new composite with a wide range of applications.
研究领域:
材料科学
·
生物医学工程
✓ 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）