JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2023
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IF 2.6
Qiongqiong Luo,Shaoheng Wang,Dehua Cai,Ning Zhang,Dewen Zeng
A ZnSO4 electrolyte solution with impurity salts such as MnSO4 and MgSO4 is often used in zinc hydrometallurgical processes over a wide temperature range. CaSO4·2H2O(s) scaling and fluorine corrosion are two encountered problems in the process. Understanding the CaF2(s) solubility behavior in MSO4 (M = Zn, Mn, Mg) aqueous solutions at various temperatures helps remove Ca2+ and F– ions from the solution. However, CaF2(s) solubility data, especially at temperatures >298 K, have not been published yet. In this work, CaF2(s) solubilities in the CaF2–CaSO4–MSO4–H2O (M = Zn, Mn, Mg) quaternary systems and its subsystems of the CaF2–MSO4–H2O (M = Zn, Mn, Mg) at 348.15 K and the CaF2–CaSO4–MSO4–H2O (M = Zn, Mg) quaternary systems and the CaF2–MgSO4–H2O ternary system at 298.15 K are systematically measured. The results show that the CaF2(s) solubility in the MSO4 (M = Zn, Mn, Mg) aqueous solution of a certain concentration at 348.15 K is considerably higher than that at 298.15 K. At 298.15 and 348.15 K, the salting-in effect of MSO4 (M = Zn, Mn, Mg) on CaF2(s) solubility is enhanced with the order ZnSO4 < MnSO4 < MgSO4. At both temperatures, CaF2(s) solubilities in CaSO4·2H2O(s)- or CaSO4(s)-saturated MSO4 (M = Zn, Mn, Mg) aqueous solutions are generally lower than those in pure MSO4 (M = Zn, Mn, Mg) aqueous solutions. Particularly, the salting-in effect of MgSO4 on CaF2 is so strong that CaF2(s) dissolves completely and is converted to CaSO4·2H2O(s) and MgF2(s) in a concentrated MgSO4 aqueous solution. Hence, this study indicates that high temperatures and high salt concentrations increase the CaF2(s) solubility, making the removal of Ca2+ and F– ions from the system challenging. Further, the existence of impurity salts MnSO4 and MgSO4 makes it more difficult.
研究领域:
化学
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材料科学
·
冶金学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2011
·
IF 4.524
Pei Pei Yuan,Bin Hong Liu,Bang Jie Zhang,Zhou Peng Li
In this work, we report a new reversible hydrogen storage composite based on 6LiBH4+CaF2. It has a theoretical hydrogen capacity of 9.6 wt % (0.09 g·ml−1) and a slightly reduced thermodynamic stability compared with pure LiBH4. The dehydrogenation of 6LiBH4 + CaF2 yielded CaB6 and a solid solution of LiH and LiF that can be rehydrogenated to form LiBH4 and CaF2. The composite revealed good reversibility of hydrogen storage regardless of the hydrogen back pressure applied during the dehydrogenation. Catalysts like TiF3, CeF3, and NbCl5 were found to enhance its dehydriding kinetics. XRD and FT-IR analyses revealed that hydrogen uptake of the composite proceeded through a reaction path involving CaH2 as the main intermediate.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Xianggang Liu,Hui Chen,Yuxin Zhao,Jingjie Zhang,Xianglong Meng,Guangchun Xiao,Zhaoqiang Chen,Mingdong Yi,Wenyu Liu,Chonghai Xu
Al 2 O 3 /CaF 2 self-lubricating ceramic materials were prepared using a low-toxicity methylacrylamide gelcasting system. The rheological properties of the Al 2 O 3 slurry were analyzed to study the effects of dispersant content, solid loading, and pH on its flowability. Optimal results were achieved with a dispersant content of 0.5 wt%, a solid loading of 54 vol%, and a pH of 9. The relative density of the resulting green body was 56 %, with a strength of 18.2 MPa. After sintering for 2 h in a vacuum furnace at 1650 °C, the material exhibited a hardness exceeding 750 HV and a bending strength above 300 MPa when the CaF 2 content was less than 10 vol%. Additionally, the tribological properties of Al 2 O 3 /CaF 2 under various conditions were investigated, revealing optimal performance at a CaF 2 content of 10 vol%. The average friction coefficient and wear rate were 0.245 and 2.96 × 10 −5 mm 3 /N⋅m, respectively, representing reductions of 48 % and 54 % compared to pure Al 2 O 3 materials. These findings demonstrate that gelcasting is an effective method for preparing self-lubricating ceramic materials, offering a new approach for fabricating complex-shaped self-lubricating ceramic components.
研究领域:
材料科学
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陶瓷工程
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Xianqiang Chen,Binfeng Zhao,Naichao Chen,Jin Cheng,Mingzhao Dang,Feng Wang,Xinwei Xu,Hong Wang
Low-temperature-fired microwave ceramics are key to realizing the integration and miniaturization of microwave devices. In this study, a facile wet chemical method was applied to synthesize homogenous nano-sized CaF 2 powders for simultaneously achieving low-temperature sintering and superior microwave dielectric properties . Pure CaF 2 ceramics sintered at 950 °C for 6 h with good microwave dielectric properties (ε r = 6.22, Q×f = 36,655 GHz, and τ f = −102 ppm/°C) was achieved. The microwave dielectric properties of the CaF 2 ceramics were further improved by introducing LiF as a sintering aid. The sintering temperature of CaF 2 -based ceramics was effectively lowered from 950 °C to 750 °C with 10 wt% LiF doping, and excellent microwave dielectric properties (ε r = 6.37, Q×f = 65,455 GHz, and τ f = −71 ppm/°C) were obtained.
研究领域:
材料科学
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电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yiming Yu,Yaowu Wei,Conghua Peng,Yuan Chen,Junfeng Chen,Bingqiang Han
Y 2 O 3 materials have become a popular candidate for preparing refractory crucibles for ultra-pure high-temperature alloy melting in recent years. However, its difficulty in sintering and poor thermal shock resistance limited its industrial application. The effect of CaF 2 on the densification microstructure, mechanical properties , and thermal shock resistance of Y 2 O 3 materials was investigated in this paper. The main purpose of this study was to optimize the amount of CaF 2 added in the preparation of Y 2 O 3 materials to improve its thermal shock resistance and get better mechanical properties. The mechanism of the densification process of CaF 2 -doped Y 2 O 3 materials was analyzed by phase analysis and microstructure. The results showed that successive doping of large Ca 2+ ions caused more lattice distortion in the Y 2 O 3 materials, and the diffusion rate of Y 3+ was increased, thus enhanced grain boundary diffusion and promoted sintering densification in the Y 2 O 3 materials. Meanwhile, the addition of CaF 2 also significantly reduced the apparent porosity and enhanced the mechanical properties of the materials. The improvement of these properties was attributed to the increased relative density of CaF 2 -doped Y 2 O 3 materials and the high sintering activity of CaF 2 . In addition, crack deflections effectively improved the thermal shock resistance of the materials. The residual flexural strength ratio of Y 2 O 3 materials doped with 1 wt % CaF 2 was increased by 21.2% after thermal shock test compared with undoped specimens.
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
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Funian Han,Liang Yu,Guanghua Wen,Jun Guo,Chunhua Ran,Shaopeng Gu
In this study, the effect of Na 2 O on the sintering and melting behavior of representative CaO-SiO 2 -CaF 2 slag were synthetically investigated by TG-DSC, DIL, XRD, SEM, XPS, and BET. As expected, most shrinkage of CaO-SiO 2 -CaF 2 slags with and without Na 2 O during the sintering process originated from solid-phase sintering, and the formation temperature of cuspidine as the sintering phase was reduced by Na 2 O to 550 °C. While Na 2 O also transformed Ca 4 Si 2 O 7 F 2 to Ca 2 NaSiO 4 F at 650 °C–880 °C and caused unexpected volume expansion, owing to increased cell volume and corresponding pore expansion. Moreover, Na 2 O reduced the melting point of CaO-SiO 2 -CaF 2 slag and promoted the volatilization of fluoride by changing the final phase before melting.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Bing Liu,Ke Sha,Meng Fei Zhou,Kai Xin Song,Cheng Chao Hu,Cheng Lu
A cold sintering process is adopted to pre-densify CaF 2 ceramics from 85.7% at 300 MPa to 91.7% at 750 MPa. Subsequent post-annealings at 1000–1150 °C lead to further improvements in densification, where great enhancements of grain size and crystallinity are also observed from the scanning and transmission electron micrographs. Significant advances in Qf values are achieved in the post-annealed CaF 2 ceramics. The optimum Qf value (80,522 GHz) is achieved after cold sintering at 750 MPa and post-annealing at 1000 °C, which is three times higher than the conventional sintered one at 1000 °C (26,448 GHz). Moreover, the obtained low- ε r (5.9–6.5) of CaF 2 ceramics suggests broad application prospects in the high-band microwave communications. A microstrip patch antenna is fabricated using the CaF 2 ceramics as the substrate, which operates at 7.89 GHz in the C-band, with an S 11 of −13.4 dB, simulated high gain and efficiency of 6.41 dBi and −0.56 dB, respectively.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
MATERIALS LETTERS
·
2023
·
IF 3
Changhai Zhang,Guoqiang Yi,Zaichun Sun,Bingchu Mei
Cr 3+ has attracted much attention as activator because of the merits such as, broadband near-infrared emission and tunable emission wavelength. However, the mixed valence of Cr 3+ in some matrix materials greatly affected its luminescence. In this work, we synthesized Cr 3+ doped CaF 2 (CaF 2 :Cr 3+ ) precursor powders with a single valence of Cr 3+ ion by coprecipitation and successfully prepared CaF 2 :Cr 3+ transparent ceramics by vacuum hot-press sintering. The obtained ceramics showed high transmittance with 83% at 1200 nm and effective broadband near-infrared emission covering 680–980 nm with a full width at half-maximum (FWHM) of 130 nm. Moreover, the photoluminescence properties of ceramics were tuned by the concentration of Cr 3+ ions.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
FERROELECTRICS
·
2024
·
IF 0.6
Li Suwen,Gao Jinyu,Shen Hongzhi,Guan Cong,Yue Jinying
CaF2: Eu3+ nanoparticles with different doping concentrations were prepared by a hydrothermal method. The surface of the prepared nanoparticles was modified by 1,2,4,5-benzenetetracarboxylic acid. The structure, morphology, photoluminescence properties, and fluorescence dynamics are studied systemically. The functionalized nanoparticles have a broad excitation band in UV-vis area and high asymmetry radio. The luminescence of Eu3+ ions in CaF2 nanoparticles is improved by 1,2,4,5-benzenetetracarboxylic acid bonded onto the surface of nanoparticles via the energy transfer process. The excited state lifetimes of functionalized nanoparticles are longer than those of un-functionalized nanoparticles. These kinds of materials have the potential to be applied in luminescent solar concentrators.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2018
·
IF 2.32
Rui Wang,Maohui Yuan,Chaofan Zhang,Hongyan Wang,Xiaojun Xu
Transition metal ions (e.g. Mn 2+ ) and lanthanide co-doped upconversion (UC) materials have attracted wide attention in recent years due to their promising application in multicolor display. Here, we report the hydrothermal synthesis and characterization of Mn 2+ doped monodisperse CaF 2 :Yb 3+ /Ho 3+ microspheres . The results of X-ray diffraction (XRD) revealed that Mn 2+ doping does not change the cubic phase of CaF 2 material but will lead to diffraction peaks shifting slightly towards higher angle due to the substitution of larger Ca 2+ by the relatively smaller Mn 2+ . Under the excitation of 980 nm continuous wave (CW) laser, these microspheres exhibit green-yellow-red tuning colors and remarkable enhancement of both red to green ratio (R/G) and red to blue ratio (R/B) when increasing Mn 2+ concentration from 0 to 30 mol%. The energy migration process between Ho 3+ and Mn 2+ was proposed and supported by time-decay and power dependence measurements of Ho 3+ UC emission. These upconversion materials may have potential applications in optical devices , color display, nanoscale lasers and biomedical imaging.
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
·
2018
·
IF 3.779
Weiwei Li,Haijun Huang,Bingchu Mei,Jinghong Song,Xiaodong Xu
This study aims to investigate the role of Y 3+ ion on microstructure, optical transmittance, and thermal properties of CaF 2 transparent ceramics. Series of nanosized CaF 2 powders doped with different concentration of Y 3+ ion were synthesized by direct precipitation method. XRD , FSEM and TEM results demonstrated that the CaF 2 nanoparticles could be tuned in size through doping of Y 3+ ion. Corresponding CaF 2 transparent ceramics were fabricated by hot-pressed (HP) method. Compared with the undoped CaF 2 sample, the transmittance of the CaF 2 ceramics improved dramatically after doping with Y 3+ ions and reached above 80% at the wavelength of 1200 nm. The effects of Y 3+ ion on the microstructure and thermal properties of CaF 2 transparent ceramics were also investigated. Overall consideration of the transmittance and thermal properties of the samples, the optimal concentration of Y 3+ ion was about 1 at.%.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
BIOMATERIALS
·
2011
·
IF 7.883
Yunlu Dai,Cuimiao Zhang,Ziyong Cheng,Ping’an Ma,Chunxia Li,Xiaojiao Kang,Dongmei Yang,Jun Lin
In this study, we design a controlled release system based on CaF 2 :Ce 3+ /Tb 3+ -poly(acrylic acid) (PAA) composite microspheres , which were fabricated by filling the pH-responsive PAA inside CaF 2 :Ce 3+ /Tb 3+ hollow spheres via photopolymerization route. The CaF 2 :Ce 3+ /Tb 3+ hollow spheres prepared by hydrothermal route possess mesoporous structure and show strong green fluorescence from Tb 3+ under UV excitation. Doxorubicin hydrochloride (DOX), a widely used anti-cancer drug, was used as a model drug to evaluate the loading and controlled release behaviors of the composite microspheres due to the good biocompatibility of the samples using MTT assay . The composite carriers provide a strongly pH-dependent drug release behavior owing to the intrinsic property of PAA and its interactions with DOX. The endocytosis process of drug-loaded microspheres was observed using confocal laser scanning microscopy (CLSM) and the in vitro cytotoxic effect against SKOV3 ovarian cancer cells of the DOX-loaded carriers was investigated. In addition, the extent of drug release could be monitored by the altering of photoluminescence (PL) intensity of CaF 2 :Ce 3+ /Tb 3+ . Considering the good biocompatibility, high drug loading content and pH-dependent drug release of the materials, these hybrid luminescent microspheres have potential applications in drug controlled release and disease therapy.
研究领域:
生物材料学
·
药理学
·
肿瘤学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）