METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2024
·Vol. 55
·期 3
·1385-1394
·
IF 2.4
Zhang Liqi,Zhang Xu,Huang Bowen,Yang Yusheng,Zhao Zengwu
Silicon has been applied in many fields, such as high-purity semiconductors, high-temperature resistant materials, optical fiber connection materials, organosilicon compounds, and alloys. In this work, silicon was extracted from the Bayan Obo tailing by high-temperature electrolysis. The reduction process of Si(IV) and the effect of CaF 2 content on the reduction process were studied in the SiO 2 –CaO–CaF 2 melt. The Si(IV) ions in the SiO 2 –CaO system with 10 wt pct CaF 2 were reduced by a one-step four-electrons transfer process. In the SiO 2 –CaO melt with 15, 20, and 30 wt pct CaF 2 , the reduction process of Si(IV) was a two-step two-electrons transfer process: Si(IV) + 2e → Si(II) and Si(II) + 2e → Si(0). The reduction process of Si(IV) to Si(II) was reversible and was controlled by diffusion. The diffusion coefficient was 1.52 × 10 −8 cm 2 s −1 . Si and WSi 2 were prepared under a current density of − 0.55 A cm −2 at 1738 K. It was found that the WSi 2 alloys were formed because of the alloying of Si(IV) and W. Graphical
研究领域:
冶金学
·
材料科学
·
电化学
·
无机化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Zhixin Wang,Yaowu Wei,Huayun Sun,Junfeng Chen,Bingqiang Han
ZrC was synthesized using sol-gel-like methods and carbothermic reduction techniques, employing Zr(OPr n ) 4 and carbon black as raw materials and CaF 2 as catalyst. High-crystallinity ZrC were obtained after a 20-minute hold at 1550°C. The effects of CaF 2 content and heat treatment temperature on structural transformation of the precursor, phase evolution, microstructural evolution and elemental composition analysis, as well as to analyze the catalytic mechanism of CaF 2 were investigated. The results indicated that this method enables effective and uniform mixing of ZrO 2 and carbon black. Adding CaF 2 promoted the deoxygenation of ZrO 2 and ZrC x O 1-x to ZrC, reducing the initial formation temperature of ZrC to 1300°C. The carbothermal reaction was nearly complete at 1500°C, yielding a composition of ZrC 0.951 O 0.049 at 1600°C. Thermodynamic calculations showed that CaF 2 react with ZrO 2 to form an intermediate phase of ZrF 4 , altering the reaction mechanism and reducing the theoretical initial synthesis temperature of ZrC to 1000°C.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Dongsheng Jiang,Yuzhe Li,Chao Zhang,Ruifang Wang,Jinpeng Zhu,Wen Chen,Yusi Che,Jilin He
Bayan Obo tailings are rich in niobium and other valuable elements; however, the phase evolution of niobium-bearing slag within these tailings remains poorly understood. This knowledge gap significantly impedes comprehensive utilization of these strategic resources. In this study, a CaO-SiO 2 -Nb 2 O 5 -5%Na 2 O-5%Al 2 O 3 -3%CaF 2 slag system was investigated to examine the phase equilibrium types, compositional characteristics, and distributional evolution under varying w (CaO)/ w (SiO 2 ) ratios and w (Nb 2 O 5 ) contents, using high-temperature equilibrium experiments. Following a 24-hour high-temperature equilibrium treatment at 1473 K under an argon atmosphere, a range of compounds including 13CaO·8SiO 2 ·Nb 2 O 5 ·CaF 2 , 2CaO·4SiO 2 ·Na 2 O·Al 2 O 3 , CaO·Nb 2 O 5 ·NaF, 2CaO·Nb 2 O 5 , and CaO·SiO 2 were identified. An increase in Nb 2 O 5 content coupled with a reduction in the w (CaO)/ w (SiO 2 ) ratio favored the formation of CaO·Nb 2 O 5 ·NaF (pyrochlore phase) and 2CaO·Nb 2 O 5 . These two phases exhibited high Nb concentrations, with the CaO·Nb 2 O 5 ·NaF (pyrochlore) phase containing up to approximately 70% Nb. The optimal smelting conditions for niobium enrichment in the pyrochlore phase were identified within the range of w (CaO)/ w (SiO 2 ) = 0.74∼0.80 and w (Nb 2 O 5 ) = 13.61%∼16.11%.
研究领域:
冶金学
·
材料科学
·
矿物加工
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2026
·
IF 9.2
Yaning Liu,Da Yang,Rui Xu,Yijue Wang,Liuyi Hu,Tianqi Yang,Min Fan,Meiqing Feng,Jianping Xu,Zhen Xiao,Ruyi Fang,Jun Zhang,Xinhui Xia,Hui Huang,Xiayin Yao,Wenkui Zhang,Yang Xia
The advancement of all-solid-state lithium metal batteries (ASSLMBs) with high energy density is significantly constrained by the inherent drawbacks of solid polymer electrolytes (SPEs), such as low room-temperature ionic conductivity, inadequate mechanical strength to prevent lithium dendrite growth, and unstable interfaces between electrodes and electrolytes.To overcome these limitations, this study introduces a synergistic modification strategy for poly(ethylene oxide) (PEO)-based SPEs by incorporating calcium fluoride (CaF2), aiming to concurrently improve bulk electrolyte properties and interfacial stability. The introduction of CaF2 effectively inhibited the crystallization of PEO by steric hindrance and Lewis acid, which made the ionic conductivity of the electrolyte reach 8.49 × 10-5 S cm-1 at 40°C (70% higher than that of the original electrolyte) and the lithium-ion migration number increased to 0.34.The composite electrolyte also demonstrates improved mechanical robustness (yield strength of 1.61 MPa) and electrochemical stability window (with decomposition voltage elevated to 5.01 V), enabling a critical current density of 0.8 mA cm-2 . Theoretical and experimental investigations reveal that CaF2 promotes the formation of a hybrid solid electrolyte interphase (SEI) enriched with LiF and Ca-Li alloys, which guides uniform lithium deposition. As a result, Li symmetric cells achieve stable cycling over 1600 hours, and LiFePO4||Li full cells retain 98.1% of their initial capacity after 300 cycles at 0.5 C. This work offers a scalable pathway for designing dendrite-suppressing SPEs through dual optimization of bulk and interfacial characteristics.
✓ 已验证
产品关联
DOI
高影响因子
NANO
·
2022
·
IF 1.438
Sisi Shi,Hongchao Geng,Leilei Sun,Yao Huang,Qingyun Cai
A turn-on fluorometric probe is designed for the determination of ascorbic acid (AA) based on the inner filter effect (IFE) between CaF 2 : Yb 3 + , Er 3 + upconversion nanoparticles (CaF 2 : Yb 3 + , Er 3 + NPs) and the oxidized 3, 3 ′ , 5, 5 ′ -tetramethylbenzidine (oxTMB). The colorless TMB can be oxidized by H 2 O 2 / Cu 2 + to blue oxTMB. Under 980 nm photoexcitation, CaF 2 : Yb 3 + , Er 3 + NPs can emit red light, which can be absorbed by the blue oxTMB, leading to the fluorescence quenching at 657 nm. As AA can reduce the blue oxTMB to colorless TMB, the fluorescence at 657 nm can be recovered with the addition of AA, which can accomplish the detection towards AA. The linear detection range of AA is from 1 to 30 μ M, and the limit of detection (LOD) of AA is 0.1 μ M.
研究领域:
分析化学
·
生物医学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2024
·
IF 3.3
Jing Pan,Yongde Yan,Yuan Deng,Xuepeng Wang,Li Ding,Xin Kong,Yun Xue,Fuqiu Ma,Kai Zhu,Wei Liu
Electrolyte is considered to be one of the key factors affecting electrolysis in the rare earth and their alloys industry. Generally, the fluoride system is chosen as the electrolyte for industrial production. However, the molten salt electrolysis method for fluoride-oxide systems is not well understood and has not been systematically studied at this stage. In order to supplement this part, lanthanum (La) ions have been chosen as the research object in this paper to systematically investigate the preparation of La–Ni alloy from LaF3–LiF-CaF2–La2O3 molten salt. A series of electrochemical methods were used to investigate the mechanism and kinetic properties of La(III) reduction on W and Ni electrodes. The electrochemical reduction properties and kinetic parameters of La were obtained. La–Ni alloy was prepared by potentiostatic electrolysis, and it was verified by detailed analysis through characterization methods. On this basis, LaNi5 intermetallic compound was successfully prepared on Ni electrode. This study provides valuable theoretical guidance for the development of La alloy preparation with fluoride salt systems in industry.
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
CERAMICS INTERNATIONAL
·
2016
·Vol. 42
·期 8
·9571-9576
·
IF 2.758
Yiguang Jiang,Jintai Fan,Benxue Jiang,Xiaojian Mao,Chunlin Zhou,Long Zhang
Transparent Er 3+ -doped CaF 2 –silica glass ceramics were prepared by the direct physical introduction of Er 3+ doped CaF 2 nanocrystals into acid-catalyzed sol–gel silica glass . The physical methods of ball milling , ultrasonic baths, and stirring were investigated to disperse Er 3+ doped CaF 2 nanocrystals in the silica sols. The CaF 2 –silica sol mixture went through gelation and heat-treatment to form Er 3+ -doped CaF 2 –silica glass ceramics. The morphology of Er 3+ doped CaF 2 in silica glass did not change after heat-treatment at 600 °C for 10 h. The experimental results showed that Er 3+ doped CaF 2 in the glass ceramic prepared with the assistance of ball milling possesses the best dispersity and homogeneity. The highest in-line transmittance of the glass ceramic reached up to 85% in visible region. Glass ceramic exhibits efficient up-conversion emissions corresponding to the Er 3+ : 4 F 9/2 → 4 I 15/2 transition and long lifetime of 4 F 9/2 level (1.73 ms) under 980 nm excitation.
研究领域:
材料科学
·
光学材料
·
纳米技术
·
光子学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2019
·Vol. 9
·期 23
·13201-13206
·
IF 3.049
Xu Yang,Maohui Yuan,Rui Wang,Xiaofan Zhao,Zining Yang,Kai Han,Hongyan Wang,Xiaojun Xu
Harnessing the color tuning capability of upconversion nanoparticles (UCNPs) is of great significance in the field of advanced bioimaging and color display. Here, we report the tunable size and upconversion luminescence (UCL) multicolor in CaF2:Yb3+/Ho3+/Ce3+ UCNPs, which were synthesized by a facile hydrothermal method. It was found that the size of these UCNPs could be controlled (from 600 to 30 nm) by varying the concentration of Ce3+ ions. Under the excitation of a 980 nm continuous-wave (CW) laser, the UCL color of these UCNPs can be tuned from green to red as the doped Ce3+ ions gradually increase from 0 to 10 mol% and the red-to-green (R/G) ratio is enhanced remarkably. It is suggested that the cross-relaxation (CR) processes between Ho3+ and Ce3+ ions contribute to the tunable multicolor and enhancement of the R/G ratio. The mechanism of these processes is well supported by the time-resolved decay and near infrared (NIR) emission measurements.
研究领域:
材料科学
·
生物成像
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TRIBOLOGY INTERNATIONAL
·
2026
·
IF 7.6
Yushuai Bai,Hui Chen,Jingjie Zhang,Guangchun Xiao,Zhaoqiang Chen,Mingdong Yi,Xianglong Meng,Chonghai Xu
Surface-localized-self-lubricating ZTA/CaF 2 ceramics were developed. • Textured reservoirs enabled the controlled release of CaF₂ during sliding. • A continuous fluorine-rich tribofilm was generated at the contact interface. • The optimum CaF₂ content was determined to be 10 vol%. • Friction and counterpart wear were reduced by 56.86% and 76.68%. To improve the dry tribological performance of ZTA ceramics, surface-localized self-lubricating ZTA/CaF 2 composite ceramics were fabricated by combining gel casting with an in-situ filling and co-sintering strategy. A systematic study was conducted on how slurry solid loading and CaF 2 loading influence the microstructure, mechanical properties, and tribological behavior of the resulting composites. The 54 vol% slurry exhibited favorable rheological properties and good sinterability, as indicated by the experimental results. The obtained sintered body achieved a relative density, Vickers hardness, flexural strength, and fracture toughness of 99.7%, 17.6 GPa, 583.6 MPa, and 6.48 MPa·m¹/², respectively. Compared with monolithic ZTA ceramics, the textured ceramic containing 10 vol% CaF 2 exhibited the best tribological performance among the investigated compositions, with reductions of 56.86% and 76.68% in the friction coefficient and wear rate of the Si 3 N 4 counterpart, respectively. Combined SEM, EDS, and XPS characterization indicated that the improved tribological behavior was mainly associated with the establishment of a continuous F-rich tribolayer under sliding contact. This tribofilm effectively minimized direct surface interaction between the sliding bodies and relieved localized stress buildup at the contact zone. These findings suggest that constructing textured lubricant-storage structures to achieve a synergistic balance between dynamic lubricant release and ceramic skeleton load-bearing capability provides a viable approach to improving the interface integrity and dry sliding performance of ZTA ceramics. Download: Download high-res image (239KB) Download: Download full-size image
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Hongchao Geng,Rongfu Peng,Junning Wang,Yuting Dong,Yuzhang Yan,Jiahui Dong,Linlang Xu,Haiyan Kang,Xu Yan,Xia Zhang,Chaopeng Wang,Yanli Mao
The development of high-performance near-infrared (NIR) photocatalysts with long-term stability broaden the range of light absorption and improve the utilization rate of solar energy have not been explored sufficiently. Herein, a novel hybrid material of upconversion nanoparticle (NPs) CaF 2 : Yb, Er, Tm decorated with TiO 2 and Au NPs has been synthesized by a simple and robust solvothermal route for NIR light active photocatalysis. It has been found that effective energy transfer occurred from CaF 2 : Yb, Er, Tm to TiO 2 and Au NPs by a nonradiative luminescence resonance energy transfer process. The enhanced activity is attributed to the nanostructured architecture that favors the efficient charge transfer and the localized surface plasmon resonance effects of Au NPs. Thus, the heterojunction showed the synergetic effects of both upconversion and localized surface plasmon resonance features, which could broaden the absorption spectrum to the NIR. Our work demonstrates that CaF 2 :Yb,Er,Tm@TiO 2 -Au could be potential candidates for NIR active photocatalysts for environmental applications.
研究领域:
材料科学
·
光催化
·
纳米技术
·
环境科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2026
·
IF 8.3
Jing Pan,Yongde Yan,Yanghai Zheng,Shengrong Guo,Xuepeng Wang,Sihao Wang,Zhiguang Du,Kaijie Wang,Yun Xue,Kai Zhu
A method for the preparation of LaNi 5 alloy by molten salt co-reduction is reported. The electrochemical co-reduction process of La(III) and Ni(II) as well as the reaction process of intermetallic compounds formation were investigated. It was confirmed that the diffusion coefficient of La(III) in LiF–CaF 2 molten salt is 4.684–8.098 × 10 −5 cm 2 s −1 at temperatures of 1113–1183 K. And the reaction activation energy was obtained to be 78.86 kJ mol −1 . And, the exchange current densities of La(III)/La(0) were determined by the Tafel (0.149–0.251 A cm −2 ) and linear polarization (0.143–0.204 A cm −2 ) methods. Furthermore, five different La–Ni intermetallic compounds were detected by studying the co-reduction reaction of La(III) and Ni(II) ions. Meanwhile, the formation potentials of La–Ni intermetallic compounds were defined by various electrochemical tests. In addition, the LaNi 5 alloy was obtained via potentiostatic electrolysis according to the electrochemical results. This study provides new insights into the electrochemistry of the LiF–CaF 2 –LaF 3 –NiF 2 molten salt and enhances the understanding of the molten salt electrolytic preparation of La–Ni alloys from co-reduction.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2024
·Vol. 59
·期 36
·16909-16917
·
IF 3.5
Xie Jingru,Fu Zhifen,Cheng Qing,Chen Chen,She Yubin,Li Xiangyi
Low temperature co-fired ceramics (LTCC) technology is extensively utilized to meet the requirements of device integration and miniaturization. Low-fired Li 3 Mg 2 NbO 6 ceramics doped with x wt% Li 2 O–MgO–B 2 O 3 –CaF 2 –SiO 2 glass (LMBCS, x = 0.5, 1.0, 1.5, 2.0) were prepared by the solid-state reaction method for applications in microwave communication materials. All samples exhibited a single-phase Li 3 Mg 2 NbO 6 structure. The addition of LMBCS glass effectively reduced the sintering temperature of Li 3 Mg 2 NbO 6 ceramics from 1250 °C to 875 °C. And adding LMBCS glass improved the Q × f value of Li 3 Mg 2 NbO 6 ceramics. The Li 3 Mg 2 NbO 6 -1.0wt% LMBCS ceramics exhibited outstanding microwave dielectric properties: ε r = 16.8, Q × f = 89,495 GHz, τ f = − 27.4 ppm/°C at 875 °C, which indicates that this ceramic is potential candidate materials for LTCC.
研究领域:
材料科学
·
电子陶瓷
·
功能材料
·
无机非金属材料
·
微波通信材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）