INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2018
·
IF 2.606
Te Qi,Zhihao Zhao,Yongqiang Sun,Hangyuan Zhao,Xiaolei Li,Huiming Ji
Porous Si 3 N 4 ceramics with a unique interlocking microstructure have been fabricated by pressureless liquid-phase sintering with YbF 3 and CaF 2 sintering additives at a relatively low temperature (1550 °C). Phase transition and mass diffusion in the low-temperature sintering process are facilitated by YbF 3 and CaF 2 producing plenty of liquid phase owing to their extremely low melting points. As the content of YbF 3 increases from 8.0 wt% to 9.5 wt% and the CaF 2 decreases from 2.0 wt% to 0.5 wt%, the conversion rate of the phase transition from α-Si 3 N 4 to β-Si 3 N 4 increases from 71.1% to 81.2% and the largest average aspect ratio of the β-Si 3 N 4 grains reaches 10.05. At the same time, the porosity declines from 40.4% to 34.9% and the flexural strength increases from 168.5 MPa to 232.1 MPa.
研究领域:
材料科学
·
陶瓷工程
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DOI
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2014
·Vol. 14
·期 5
·3380-3386
·
IF 1.339
Yu Shiyong,Zhi Yunxia,Su Haiquan
A series of rare-earth ions (Er3+ and Yb3+) Co-doped CaF2 upconversion luminescent nanomaterials have been successfully prepared via a facile hydrothermal method using pluronic p123 (p123), pluronic F127 (F127) and sodium citrate as surfactants at 180
°C with different reaction time. The crystallographic phase, size and morphology can be controlled by simply tuning the reaction parameters such as the types of surfactants and the reaction time. It is found that reaction time and surfactant play a key role in forming the nanocrystals
with different morphologies. X-ray diffraction, field-emission scanning electron microscopy FE-SEM, and photoluminescence spectra were used to characterize the structure, morphology and upconversion luminescence properties of CaF2:Er3+/Yb3+ upconversion nanomaterials,
respectively. The experimental results indicate that three monodispersive and highly uniform CaF2:Er3+/Yb3+ nanocrystals with mean size of 200 nm, 3 um, and 700 nm have cubic and sphere shapes, respectively. While the possible mechanisms of upconversion luminescence
are analyzed by the diagram of proposed energy transfer mechanisms, the schematic energy level diagrams showing typical upconversion processes for Er3+ also reveals that the as-synthesized CaF2:Er3+/Yb3+ nanomaterials may be in the cubic structure
with space group Fm-3m, in which Ln3+ cations occupy crystal lattice positions with lower point symmetry, leading to a high upconversion efficiency under the excitation of a 980 nm diode laser.
研究领域:
材料科学
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纳米技术
·
发光材料
·
稀土掺杂
·
光学材料
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DOI
高影响因子
Micro & Nano Letters
·
2018
·Vol. 13
·期 3
·393-396
·
IF 0.841
Ting Fan,Jiantao Lü,Yongfa Huang,Guoji Li
Monodisperse oleic acid (OA) modified Eu 3+ and Li + codoped CaF 2 nanoparticles are presented in this work. The as-obtained nanoparticles, with a hexagonal shape, can be well-dispersed in organic apolar solvents. The incorporation of Li + ions in CaF 2 :Eu 3+ does not lead to new crystalline phases. The main diffraction peaks are found to shift to small angles when codoped with 7 mol% Li + , while a reverse shift can be noted with the codoping amount increasing to 9 mol% Li + , indicating that the codoped Li + enables the crystal field environment of Eu 3+ to be changed. The excitation and luminescence intensities of all peaks indexed to Eu 3+ have enhanced apparently when codoped with 7 mol% Li + ions. The lifetime of the 5 D 0 state of Eu 3+ ions is also increased by introducing 7 mol% of Li + ions.
研究领域:
材料科学
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光学
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DOI
高影响因子
Coatings
·
2026
·Vol. 16
·期 6
·650
·
IF 3.4
Tingchen Yan,Yaming Jia,Ning Liu,Hongshui Wang,Chunyong Liang
This study aimed to address the clinical challenge of secondary caries prevention in dental restorations. Leveraging the sustained fluoride-releasing capacity of calcium fluoride (CaF2) and the broad-spectrum antibacterial activity of zinc oxide (ZnO), we designed and synthesized a novel core–shell CaF2@ZnO nanoparticle filler to synergistically enhance the functional performance of dental resin composites. The filler was successfully prepared via a co-precipitation-hydrothermal method, and its well-defined core–shell architecture was systematically confirmed using XRD, SEM, and TEM. When incorporated into the resin matrix at 10 wt.% loading, the composite containing CaF2@30ZnO demonstrated optimal overall performance. Notably, this formulation enabled sustained fluoride ion release, potent antibacterial efficacy, and excellent in vitro cytocompatibility. Collectively, these findings demonstrate that the CaF2@ZnO nanofiller confers multifunctional benefits—including improved mechanical integrity, long-term fluoride release stability, and targeted antibacterial action—thereby holding significant promise for clinical application in mitigating secondary caries around resin-based restorations.
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DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2017
·
IF 3.012
Wen Li,Aijia Wei,Lihui Zhang,Xiaohui Li,Xue Bai,Zhenfa Liu
The surface of pure Li 4 Ti 5 O 12 was modified with CaF 2 via a chemical co-precipitation method followed by calcination at 400 °C for 5 h in order to study the reaction mechanism of the fluoride modification process. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were used to confirm the structure and morphology of the material. After the modification, the structure of Li 4 Ti 5 O 12 was unchanged, as F − ions reacted with Ca 2 + ions to form CaF 2 instead of reacting with Li 4 Ti 5 O 12 . A consecutive CaF 2 coating layer was not formed on the surface of Li 4 Ti 5 O 12 ; instead, many microscale CaF 2 crystals stacked on the Li 4 Ti 5 O 12 particles. The stacked CaF 2 crystals could not only reduce electrode polarization, but also partially suppress reductive decomposition, resulting in the formation of a thinner SEI film, thereby reducing resistance of the SEI film ( R sei ) and the charge-transfer resistance ( R ct ), both of which were beneficial to the electrochemical performance of Li 4 Ti 5 O 12 . The 2 wt% CaF 2 -modified Li 4 Ti 5 O 12 exhibited a superior rate capacity, with discharge capacities between 0 and 3 V of 227.8, 215.8, 207.6, 190.6, 180.2, and 157.6 mAh g − 1 at rates of 0.2, 0.5, 1, 3, 5, and 10 C (1 C = 250 mAh g − 1 ), respectively. Moreover, the 2 wt% CaF 2 -modified Li 4 Ti 5 O 12 showed a discharge capacity retention of 96.7% after 125 cycles at a rate of 3 C, higher than that of pure Li 4 Ti 5 O 12 (94.4%), which was due to the fact that CaF 2 modification enhanced the capability of the material to resist HF attack during the discharge/charge processes.
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 5
·2676-2681
·
IF 3.108
Tuerxun Aidilibike,Junjie Guo,Lili Wang,Xiaohui Liu,Yangyang Li,Weiping Qin
Under 978 nm near infrared (NIR) excitation, ultraviolet (UV) upconversion (UC) emissions from Pb2+ ions in CaF2:Pb2+,Yb3+ were first observed at room temperature. The UC emission centered at ∼383 nm was ascribed to the 3P0 → 1A1g (1S0) transition of Pb2+ ions. From transient measurements, the UC process was found to be dominated by the energy transfer process: three excited Yb3+ ions simultaneously transfer their energy to one Pb2+ ion. With the increase in Pb2+ concentration, the cooperative luminescence from 3-Yb3+ clusters decreased gradually until it was extinguished. The cooperative sensitization to one Pb2+ ion comes from three excited Yb3+ ions, which is a four-ion process and exhibits a third power dependence on the NIR pumping power.
研究领域:
光学材料
·
光子学
·
发光光谱学
·
稀土掺杂
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DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Xuepeng Wang,Yongde Yan,Yanghai Zheng,Jing Pan,Qingguo Zhang,Yun Xue,Milin Zhang,Kai Zhu
The efficient recovery of the radioactive elements uranium (U) and plutonium (Pu) from radioactive calcium fluoride slag is of great significance for the sustainable utilization of nuclear resources and environmental protection. Molten salt electrolysis technology based on pyrometallurgy, characterized by a streamlined process and the absence of secondary waste generation, is widely regarded as the most promising approach for the treatment of such radioactive residues. However, the physicochemical properties of molten salts and the underlying electrode reaction mechanisms under high-temperature conditions remain insufficiently understood and lack systematic investigation. In this study, by comparing the electrochemical parameters and physical-chemical properties of different molten salt systems, it was found that the CaCl 2 -CaF 2 molten salt system is a suitable choice for treating radioactive calcium fluoride waste. Due to the high radioactivity of plutonium (Pu), cerium (Ce) was employed as a chemical analogue of plutonium to investigate the electrochemical extraction of actinides in CaCl 2 -CaF 2 molten salt systems. The electrochemical behavior of Ce(III) on a W electrode and related kinetic parameters were investigated. Electrochemical analysis reveals that Ce(III) undergoes a quasi-reversible and diffusion-controlled reduciton on inert W electrode. The process shows distinct adsorption and desorption, likely attributable to the coexistence of Cl − and F − ions. To better extract Ce, nickel (Ni) ions were introduced into the molten salt. The co-deposition behavior of Ce(III) and Ni(II) on the W electrode was investigated by electrochemical methods. The thermodynamic parameters of Ce-Ni intermetallic compounds at the experimental temperature were calculated. The results show that CeNi 5 has a distinct thermodynamic advantage in formation. X-Ray Diffraction (XRD)， Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS) characterization analyses confirmed the successful extraction of Ce in the form of the CeNi 5 intermetallic compound.
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DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2016
·
IF 2.435
Weihao Ye,Xiaotang Liu,Qiying Huang,Zhiping Zhou,Guangqi Hu
Europium doped Calcium fluoride (CaF 2 :Eu 2+ ) nanoparticles have been synthesized by co-precipitation method using different surfactants, in which anhydrous ethanol was used as solvent and the nanoparticles was sintered in air. The self-reduction was observed in the as-prepared CaF 2 :Eu 2+ nanoparticles and can be explained by charge compensation model based on the substitution. Scanning electron microscope (SEM) and X-ray power diffraction (XRD) showed that the nanoparticles were about 50 nm⿿1 μm and in a single phase. A broad emission centered at 425 nm due to Eu 2+ 4f 7 ⿿4f 6 5d 1 transition has been observed with excitation bands between 337 and 385 nm by the fluorescence spectrometer. The corresponding excitation spectra showed a wide excitation range in the violet region due to 4f 7 ( 8 S 7/2 ) ⿿ 4f 6 5d 1 (t 2g ) The luminescent properties of the phosphor was thoroughly examined. Furthermore, the effect of using different surfactants on the sizes of CaF 2 :Eu 2+ nanoparticles, related mechanisms was also investigated.
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DOI
高影响因子
IRONMAKING & STEELMAKING
·
2021
·
IF 1.679
Liang Yu,Wenbo Jiang,Shaopeng Gu,Ping Tang,Zhe Wang,Guanghua Wen
The reaction behaviour and mechanism of carbon and mould fluxes during the heating process were deeply considered through TG-FTIR, XRD, DSC, and SEM techniques. The results showed that: there were four main stages of weight loss for slags during heating process. One hundred to 300 °C and 300–500°C were the volatilization of free water and bound water, respectively. Five hundred to 800°C was the decomposition process of carbonate. However, at 800–1400°C, CaO–SiO2–CaF2 slag was the reaction of slag component themselves. CaO–SiO2–CaF2–C series slags were the reaction behaviour between carbon and slags (C and Ca2SiO4, Ca4Si2O7F2). The DSC and SEM analysis illustrated that the solid phase reaction temperature range of CaO–SiO2–CaF2–C being 1320–1370°C was larger than that of CaO–SiO2–CaF2 being 1070–1250°C. Additionally, CaO–SiO2–CaF2 slag was completely molten at 1400°C, while CaO–SiO2–CaF2–C did not, suggesting that the sintering and melting process were suppressed by carbon.
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高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2016
·Vol. 16
·期 4
·3679-3683
·
IF 1.338
Li Suwen,Huang Qingqing,Jiang Yi,Hu Min
A series of Ce3+-Yb3+ co-doped CaF2 nanoparticles were prepared by a hydrothermal synthesis method. The structure, morphology, photoluminescence properties, and fluorescence dynamics were studied systemically. Under the excitation of the 5d level of
Ce3+, an efficient energy transfer from Ce3+ to Yb3+ occurred, and the efficient near-infrared emission at 900–1050 nm matching to the energy of Si band gap of Si-based solar cells was observed. The lifetime of Ce3+ decreased, and the inner
quantum efficiency increased with increasing Yb3+ concentration. The quantum efficiency dependent on Yb3+ concentration was calculated, and the maximum efficiency approached 186%. As a down-conversion luminescent convertor, this kind of material can be used in front of
Si-based solar cells to reduce thermalization loss and enhance conversion efficiency of solar cells.
研究领域:
材料科学
·
光物理学
✓ 已验证
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2025
·
IF 4.2
Jinjie Zheng,Honglie Shen,Yufang Li,Huanlun Tong,Jingzhe Zhang,Zhihong Xie
In this study, a novel fabrication method for a bilayer film consisting of the Bi 2 Mo 3 O 12 :Eu 3+ and CaF 2 was developed. Bi 2 Mo 3 O 12 :Eu 3+ film was prepared using the chemical solution method, eliminating the need for separate phosphor preparation. The excitation spectra of Bi 2 Mo 3 O 12 :Eu 3+ displayed a broad band within the range of 300 and 420 nm. Under ultraviolet (UV) excitation, the material emitted strong red luminescence, with a dominant peak around 615 nm, which coincides with the absorption range of silicon solar cells. Additionally, a CaF 2 anti-reflection layer was introduced to enhance optical transmittance. The average transmittance of the Bi 2 Mo 3 O 12 :Eu 3+ @CaF 2 bilayer film reached 92.3%, representing a 0.7% increase compared to the bare glass substrate (91.6%). As a proof-of-concept, applying Bi 2 Mo 3 O 12 :Eu 3+ @CaF 2 to this bilayer film on photovoltaic modules resulted in an absolute enhancement of 0.19% in power conversion efficiency.
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产品关联
DOI
高影响因子
ACS Nano
·
2026
·
IF 17.3
Shuohan Liu,Shaojie Zhang,Feng Chi,Wensheng Tian,Lingti Kong,Pan Liu,Hui Pan,Hengdao Quan,Shenmin Zhu
Inspired by the perfect integration of structure and function in mammalian bone, a general strategy for achieving high performance solid-sol electrolyte in lithium metal batteries is developed by utilizing naturally abundant calcium fluoride (CaF2) as the inorganic matrix. With a small amount of organic solvent (only 12.8 wt %), a continuous ion transport network is established through multilevel nonbonding interactions between inorganic CaF2 and organic solvent. While CaF2 matrix offers excellent stability and robust mechanical support, the organic electrolyte network ensures high ionic conductivity and intimate interfacial contact. Furthermore, an integrated solid–electrolyte interphase enriched with LiF and Li–Ca alloy is generated via in situ reaction between the CaF2 matrix and Li, leading to remarkably enhanced interfacial reaction kinetics and greatly suppressed Li dendrite growth. Consequently, the solid-sol electrolyte exhibits a wide electrochemical window of 5.26 V and a high Li+ transference number of 0.77 at room temperature. When matching LiFePO4 cathodes, the batteries enable stable cycling over 200 cycles even at elevated temperatures up to 100 °C. Also, the created solid-sol electrolyte based on inorganic CaF2 displays an interesting flame-retardant property. Notably, this strategy demonstrates extensibility to diverse liquid electrolytes, allowing straightforward tuning of solid-sol electrolyte properties for targeted performance optimization.
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PubMed
高影响因子
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