JOURNAL OF LUMINESCENCE
·
2014
·
IF 2.367
Jiansheng Huo,Jiadan Zhu,Shunhua Wu,Haijie Zhang,Qianming Wang
Red emissive phosphors of YTa 1− x Nb x O 4 :Eu 3+ ( x =0–1) have been successfully synthesized by a molten salt method. Powder characteristics were studied by X-ray diffraction, scanning electron microscopy and photoluminescence spectroscopy. The effects of Nb concentration ( x ), flux nature and firing temperature on photoluminescence behavior of YTa 1− x Nb x O 4 :Eu 3+ were extensively investigated. The results showed that the photoluminescence spectra of the samples exhibited strong red emissions (615 nm) upon the ultraviolet excitation and the emission intensities strongly dependent on the host-lattice composition and particle morphology .
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2024
·Vol. 26
·期 46
·28971-28979
·
IF 2.9
Yuhan Fan,Yongze Cao,Meiling Li,Sai Xu,Yichao Wang,Xizhen Zhang,Jinsu Zhang,Baojiu Chen
A series of Tb3+, Pr3+ and Dy3+ monodoped CaTa4O11(CTO) persistent luminescence (PersL) phosphors have been successfully synthesized using the molten salt method with KCl flux. The PersL color is green and orange for Tb3+ and Pr3+ or Dy3+ doped samples, respectively. The trap depth of Tb3+, Pr3+ and Dy3+ monodoped CTO is 0.33, 0.31 and 0.30 eV, respectively. The PersL time of 3 mol% Tb3+, 1 mol% Pr3+ and 1 mol% Dy3+ monodoped samples is 52.20, 35.00 and 59.46 s, respectively. Tb3+, Pr3+ and Dy3+ monodoped CTO phosphors can be used in luminescence displays and anti-counterfeit labels under commercial 254 nm UV light.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Xuekai Wang,Yongze Cao,Yuanbing Mao,Tianshuo Liu,Xianglan Yan,Lei Li,Jinsu Zhang,Baojiu Chen
Low phonon tantalate-based phosphors with a layer structure are considered to have excellent upconversion luminescence (UCL) intensity, which could be reduced due to the existence of impure phase defects and inappropriate doped rare earth ions. To improve their UCL performance, we have prepared single-phase CaTa4O11:Er3+/Yb3+ samples by a molten salt synthesis (MSS) using KCl as the reaction medium and compared its UCL properties with counterparts made by a conventional solid-state reaction (SSR) in this study. We have demonstrated that the MSS samples have a much higher UCL intensity under 980 nm laser excitation than the SSR ones due to accurate replacement of Ca2+ sites by Er3+/Yb3+ in high-purity single-phase MSS samples. We have further enhanced the green UCL intensity of the MSS samples by 1.57 times via acid picking (AP). Under 980 nm laser excitation at a high powder density of 61.3 W/cm2, the green UCL intensity of the MSS-AP samples can reach 3.72 times that of the SSR-AP samples. For potential luminescence thermometry applications, the maximum absolute sensitivity (SA) of the MSS-AP samples reaches 0.01316 K–1 at 501 K based on the luminescence intensity ratio. This study shows that CaTa4O11:Er3+/Yb3+ phosphors prepared by the MSS method are single-phase samples with excellent pure green UCL as a suitable temperature sensing material.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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
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
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
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Yawei Wang,Shunhang Wei,Xiaoxiang Xu
Solid solutions between SrTaO 2 N and CaTaO 2 N, i.e. Sr 1-x Ca x TaO 2 N (0.0 ≤ x ≤ 1.0) were synthesized and investigated as photocatalysts for water oxidation and reduction. A wealth of important parameters such as Ta-(O, N) bond length, Ta-(O, N)-Ta bond angle, band gap and band edge positions can be successively tuned by varying Sr/Ca molar ratios at A site. These solid solutions work well as photocatalysts to drive water splitting reactions under visible light illumination which clearly outperform their parent compounds SrTaO 2 N and CaTaO 2 N. Apparent quantum efficiency as high as 1.67% at 420 ± 20 nm was achieved on Sr 0.4 Ca 0.6 TaO 2 N (x = 0.6) which stands as the highest one reported for SrTaO 2 N and CaTaO 2 N to date. This simple approach by cation control at A site serves as a useful tool to tailor photocatalytic properties of perovskite oxynitrides, opening new playgrounds for the design and development of these tempting compounds as efficient photocatalysts.
研究领域:
材料科学
·
光催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Li Liu,Ping Ouyang,Yuhan Li,Youyu Duan,Fan Dong,Kangle Lv
Deeply photocatalytic oxidation of nitrogen oxides is still difficult to achieve, mainly limited by few intrinsic active sites and inefficient carrier separation of photocatalysts. Accordingly, we develop a simple room temperature tactic to introduce oxygen vacancies (OVs) into Bi 3 TaO 7 (BTO). Based on solid experimental and DFT theoretical supports, we explore the mechanism of NO removal over OVs decorated BTO (OVs-BTO). OVs can not only alter the distribution of local electrons to result in the formation of a fast charge transfer channel between OVs and the adjacent Ta atoms, which improves the transport rate of photogenerated carriers; but also function as active sites to adsorb small molecules (NO, O 2 and H 2 O), which being activated and positively drive the NO oxidation reaction. In order to investigate a possible reaction path, a combination of in-situ DRIFTS and simulated Gibbs free energy reveals that the intermediate products of OVs-BTO are helpful to promote the deep oxidation of NO to NO 3 - , while pristine BTO is more likely to produce NO 2 intermediate toxic by-products, which greatly hinders the deep photocatalytic oxidation of NO. This work provides insights into the role of OVs in photocatalysts, and also points out a guideline for the mechanism of semiconductor photocatalysts in eliminating gaseous pollutants .
研究领域:
环境科学
·
材料科学
·
理论化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
Jun Wang,Xiaoyu Chong,Liang Lv,Yuncheng Wang,Xiaolan Ji,Haitao Yun,Jing Feng
The primary purpose of this work is to optimize the thermophysical properties of rare-earth tantalate ceramics using the high-entropy effect. Here, the high-entropy rare-earth tantalate ceramic (Y 0.1 Nd 0.1 Sm 0.1 Gd 0.1 Dy 0.1 Ho 0.1 Er 0.1 Tm 0.1 Yb 0.1 Lu 0.1 )TaO 4 ((10RE 0.1 )TaO 4 ) is synthesized successfully. The lattice distortion and oxygen vacancy concentration are characterized firstly in the rare-earth tantalates. Notably, compared with single rare-earth tantalates, the thermal conductivity of (10RE 0.1 )TaO 4 is reduced by 16%–45% at 100 °C and 22%–45% at 800 °C, and it also presents lower phonon thermal conductivity in the entire temperature range from 100 to 1200 °C. The phonon thermal conductivity (1.0–2.2 W m −1 K −1 , 100–1200 °C) of (10RE 0.1 )TaO 4 is lower than that of the currently reported high-entropy four-, five- and six-component rare-earth tantalates. This is the result of scattering by the ferroelastic domain, lattice distortion associated with size and mass disorder, and point defects, which target low-, mid- and high-frequency phonons. Furthermore, (10RE 0.1 )TaO 4 , as an improved candidate for thermal barrier coatings materials (TBCs), has a higher thermal expansion coefficient (10.5×10 −6 K −1 at 1400 °C), lower Young's modulus (123 GPa) and better high-temperature phase stability than that of single rare-earth tantalates.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2024
·
IF 5.2
Jun Wang,Jianyu Li,Chunyu Jiang,Jianbo Song,Xing Yang,Xiaolong Ma,Kailiang Luo,Peng Wu,Xiaoyu Chong,Jing Feng
Thermal barrier coatings (TBCs) materials with lowered thermal and oxygen ion conductivity can provide thermal and oxidative protection for high temperature hot-end components in aeronautical engines and gas turbines . The rare-earth tantalate RETaO 4 (RE = Dy, Gd and Sm) ceramics with monoclinic (m) phase were successfully synthesized via spark plasma sintering . Oxygen vacancies responsible for the thermal and oxygen ion conductivities of RETaO 4 were demonstrated by atomic-resolution energy dispersive X-ray and X-ray photoelectron spectroscopy . Among the three samples, DyTaO 4 has excellent oxygen/thermal barrier performance. Compared to the current service thermal barrier coating material ZrO 2 -8 wt% Y 2 O 3 (8 YSZ), DyTaO 4 has an ultra-low oxygen ion conductivity benefiting from low oxygen vacancy concentration and strong stretching force constants. The intrinsic thermal conductivity of DyTaO 4 is 68.2% less than that of 8 YSZ . Additionally, the thermal expansion rate curves indicate that the phase transformation does not happen from room temperature to 1200 °C. The above results demonstrate that high-growth rate thermally grown oxide can be retarded by creating dense DyTaO 4 coating with lowered thermal and oxygen ion conductivity.
研究领域:
材料科学
·
航空工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yaochen Si,Lingfeng Li,Ruida Wang,Songting Zhang,Yingnan Cao,Hongyu Li,Shixian Zhao,Hongxia Li,Jing Feng
With the development of high power and high thrust-weight ratio aeronautics and astronautics, aircraft engines and gas turbine technology, the development of thermal barrier coating (TBCs) material is an enormous challenge, which requires both high temperature stability and resistance to molten calcium-magnesium-aluminosilicate (CMAS) corrosion. In this study, five high-entropy rare-earth tantalate (5RE 0.2 )TaO 4 (Re=Y, Gd, Dy, Ce, Sm, La, Yb) ceramics were prepared by high temperature solid state reaction. The phase composition, microstructure, thermophysical and mechanical properties and CMAS corrosion resistance of the obtained high-entropy (5RE 0.2 )TaO 4 ceramics were systematically investigated. The as-prepared five high-entropy rare-earth tantalate (5RE 0.2 )TaO 4 ceramics had monoclinic structure and uniform composition. The five (5RE 0.2 )TaO 4 ceramics all had lower Young’s modulus (135.06∼158.63 GPa), Vickers hardness (3.7∼6.2 GPa), fracture toughness (2.30-2.80 MPa·m 1/2 ) and brittleness index (1.45-2.53 μm –1/2 ) than that of YSZ. The thermal expansion rate and thermal expansion coefficients of the five (5RE 0.2 )TaO 4 ceramics were close to each other but showed higher value than that of single RETaO 4 (RE= Gd, Dy, Sm or Y) and lower value than that of YSZ. The thermal diffusivities and thermal conductivity of the five (5RE 0.2 )TaO 4 ceramics were lower than that of YSZ, YTaO 4 and GdTaO 4 at all temperature. During molten CMAS corrosion, CMAS melt diffused into the (5RE 0.2 )TaO 4 ceramics and then corroded (5RE 0.2 )TaO 4 grains, thereby forming a corrosion area composed of reaction layer and penetration layer. The CaO in penetrated CMAS melt could react with Ta element in (5RE 0.2 )TaO 4 ceramics to generate Ca 2 Ta 2 O 7 in the reaction layer and reduce the content of CaO in the penetrated CMAS melt, which increased the viscosity of the CMAS melt and inhibited the further penetration of CMAS into the ceramics. Based on the obtained results, the CMAS corrosion of (5RE 0.2 )TaO 4 ceramics was primarily controlled by the Ca 2 Ta 2 O 7 formation and the CMAS penetration.
研究领域:
材料科学
·
航空工程
✓ 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）