Journal of Materiomics
·
2020
·
IF 5.797
Xuefeng Liu,Quan Zhang,Jianmin Liu,Tao Wang,Yanqiao Xu,Jian Liang,Feng Jiang,Guo Feng,Weihui Jiang
The simultaneous control of crystal phase stability and one-dimensional growth has always been the major challenge for the preparation of tetragonal zirconia whiskers. In this study, we report a facile molten salt processing that utilizes CaF 2 as a stabilizer and adsorbent to meet the phase and morphology requirements. The processes of stabilization, phase transition, ion adsorption and formation of special morphology involved in zirconia growth were investigated by XRD, IR, SEM, DTA-TG and TEM. By controlling the amount of CaF 2 (15 wt%) added in the reaction precursor, tetragonal zirconia whiskers with a desired aspect ratio (>16) can be synthesized, which show single crystalline nature and [001] preferred direction. Ca ions doped at low temperature inhibit the occurrence of phase transition, which allows the tetragonal structure to be retained to room temperature. The inducement and pattern of whisker growth are supposed to be F-adsorption and screw dislocation elongation, respectively. The specific selectivity of surface adsorbed ions to certain zirconia crystal planes reduces or even inhibits the epitaxial growth rate in this direction, offering a viable avenue for the morphology modulation of inorganic nanomaterials.
研究领域:
材料科学
·
晶体学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2024
·
IF 5.7
Linglu Kuang,Feng Zhang,Jian Zhang,Xiaodie Zhu,Xu Tian,Jianxiong Shao,Yichun Liu,Xuhui Xu,Zhichao Liu
Optical materials are widely used in the information coding, display, and anti-counterfeiting fields due to their tunable color. However, the regulation of the color change in a material is mainly achieved by co-doping with different ions to achieve multimode luminescence, which greatly increases the difficulty of material synthesis. Herein, CaF2:Eu with different doping amounts of Eu ions as an anti-counterfeiting material is synthesized in one step by a simple high-temperature solid-state method. The concentration of Eu can adjust the reduction ratio of Eu ions and give the material multicolor emission. Moreover, X-ray-induced ion reduction achieves the multicolor emission of Eu2+ and Eu3+ ions in a single matrix of CaF2:Eu. This achieves radio-photo luminescence (RPL). In addition, the mechano-luminescence (ML) of CaF2: 0.5%Eu has also been confirmed. These findings provide unique insights into the design of highly integrated advanced anti-counterfeiting technologies using multi-stimuli-responsive luminescent materials.
研究领域:
光学材料
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材料科学
·
防伪技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Jintao Wang,Du Hong,Xin Zhong,Liping Huang,Yaran Niu,Hong Li,Xuebin Zheng,Jinliang Sun
The abradable sealing coatings (ASCs) matched with ceramic matrix composites (CMCs) can improve engine efficiency and reduce fuel consumption. A study of plasma-sprayed porous Yb 2 Si 2 O 7 -20 vol% CaF 2 with various contents of poly-p-hydroxybenzoate (PHB) as ASCs compatible with CMCs is reported. The microstructure and phase composition, Rockwell hardness, wear behaviors and abradability of the coatings were comparatively studied. The results show that the porosity increased and the hardness decreased as the PHB content was increased, and the coating containing 20 vol% PHB had a minimum hardness of about 65.2 HR45Y and a maximum porosity of about 39.2%. The friction coefficients and IDR values decreased, wear depth and volume wear rates of the coatings effectively improved with the increase of porosity. The wear mechanisms were analyzed based on the observation of the worn surfaces. This work might provide some guidance for the design and application of ASCs for CMCs.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2024
·Vol. 12
·期 31
·2401320
·
IF 8
Wenting Zhao,Leipeng Li,Tao Li,Jianrong Qiu,Yanmin Yang
Persistent luminescence (PersL) has attracted considerable attention in the last two decades for its potential applications in the fields of emergency indicators, energy-saving lighting, biomedical imaging, and dynamic anti-counterfeiting. However, the wavelengths of PersL reported so far usually fall into the visible and near-infrared range. The preparation of advanced optical materials bearing UV PersL remains elusive. Here the PersL characteristic of CaF 2 :Gd 3+ is systematically studied. After exposure to X-ray radiation, CaF 2 :Gd 3+ continues to emit UV-B (UVB) PersL peaking at 313 nm, corresponding to the 6 P 7/2 → 8 S 7/2 transition of Gd 3+ . By virtue of X-ray photoelectron spectroscopy measurements, the valence variation model is excluded to explain the UVB PersL of CaF 2 :Gd 3+ . Finally, it is demonstrated that such UVB PersL of CaF 2 :Gd 3+ can be used for static labeling and dynamic tracing.
研究领域:
材料科学
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光学材料
·
生物医学成像
·
防伪技术
✓ 已验证
DOI
高影响因子
ACS Applied Optical Materials
·
2024
·
IF 0
Xunsheng Zhou,Binqing Zhao,Lu Yao,Wanting Gui,Longfei Chen,Chao Li,Shi Zhang,Cai Lin Wang
Eutectic scintillators with 6Li-containing thermal neutron absorbers are capable of efficient thermal neutron detection due to lamellar or rod-like optical waveguide structures formed by directional solidification. However, developing stable and bright eutectic scintillators with excellent neutron imaging capability remains a challenge. Here, the performance parameters for the scintillator have been substantially improved by the Al3+ codoping strategy in the LiF-CaF2:Eu2+ system. Due to the Al3+ codoping, the photoluminescence quantum yield (PLQY) is enhanced from 55% to 80%, the light yield is increased from 11,000 to 16,000 photons/thermal neutron, and the scintillation decay time is shortened by about 30 ns. It was shown that Al3+ codoping can effectively reduce the low-frequency shallow-energy level traps. Furthermore, large-sized (50 × 50 × 1.5 mm) translucent LiF-CaF2:Eu2+, Al3+ eutectic ceramics have been fabricated for an Anger-logic position-sensitive detector to realize two-dimensional (2D) thermal neutron detection. A codoped LiF-CaF2 eutectic scintillator provides a ∼1 mm spatial resolution and thermal neutron detection efficiency 16% higher than that of a commercial GS20 scintillator. This research paves the way for the application of large-area eutectic scintillators for efficient thermal neutron detection.
研究领域:
材料科学
·
核物理
·
光学
✓ 已验证
DOI
DENTAL MATERIALS
·
2022
·
IF 5.687
Jing Cao,Dan-Lei Yang,Dan Wang,Jie-Xin Wang
Objective The objective of this study is to develop novel CaF 2 /SiO 2 nanoclusters (NCs) fillers, which can endow the dental resin composites (DRCs) with excellent mechanical properties , stable and sustained fluoride ion release, and good antibacterial activity . Methods The CaF 2 /SiO 2 NCs were efficiently fabricated by assembling CaF 2 /SiO 2 nanoparticles (NPs) as building blocks with a spray-drying technology. CaF 2 /SiO 2 NCs with different SiO 2 coating amounts (20 wt%, 50 wt% and 80 wt%) were incorporated into the DRCs at the filler content of 55 wt% for the measurement of mechanical properties including flexural strength , flexural modulus, compressive strength , and hardness. The effect of the filling amount of CaF 2 /50SiO 2 NCs (50 represents 50 wt% SiO 2 coating amount) in the DRCs was investigated, while CaF 2 /50SiO 2 NPs were adopted as comparison group. The fluoride ion release and antibacterial activity of the DRCs with the optimal mechanical performances were evaluated. Furthermore, the statistical analyses were performed for mechanical properties. Results Spherical CaF 2 /50SiO 2 NCs with an average size of 2.4 µm were obtained at the feed rate of 7.4 mL/min and the CaF 2 /50SiO 2 NPs solid content of 2 wt% in the suspension. The optimum comprehensive performances of the DRCs can be achieved by filling 55 wt% CaF 2 /50SiO 2 NCs. Compared with CaF 2 /50SiO 2 NPs, the filling amount of CaF 2 /50SiO 2 NCs was increased by 5 wt% (50–55 wt%), and under the same filling amount of 50 wt%, the flexural strength, flexural modulus, compressive strength, and hardness of the DRCs containing CaF 2 /50SiO 2 NCs were improved by 9.8%, 17.7%, 7.5% and 69.8%, respectively. Furthermore, the DRCs filled with 50 wt% CaF 2 /50SiO 2 NCs exhibited more cumulative F-release by 126% and more stable F-release rate than the counterpart filled with 50 wt% CaF 2 /50SiO 2 NPs after immersed for 1800 h. And 55 wt% CaF 2 /50SiO 2 NCs filled DRCs could inhibit the growth of S. mutans, reaching an antibacterial ratio of 93%. Significance The spray-dried CaF 2 /50SiO 2 NCs are promising fillers for the development of high-performance multifunctional DRCs.
研究领域:
材料科学
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牙科学
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生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
·
2025
·
IF 8.9
Zhihui Zhang,Jianxin Deng,Shenghan Cao,Ran Wang,Jiaxing Wu,Yang Lu,Yichen Bao
The (CF x ) n /CaF 2 -ZrO 2 interlaced coating was prepared using electro-jet mask printing technology. The effects of CaF 2 content (0, 25, 50 wt%) on its microstructure, adhesion strength, and wear properties against 304 stainless steel balls at high temperatures (25, 200, 400 °C) were investigated. The results indicated that the interlaced structure of the coating helped prevent the loss of lubricant particles and reduced the actual contact area between the counterparts. The addition of CaF 2 reduced the surface roughness and porosity of the (CF x ) n coating and suppressed thermal weight loss and fatigue peeling of the coating. At 25 °C, the (CF x ) n -ZrO 2 interlaced coating showed the lowest friction coefficient of ∼ 0.13, although the brittle CaF 2 particles hindered lubrication. At 200 °C, the presence of CaF 2 reduced the wear rate of the friction pair. At 400 °C, the interlaced coating with 25 wt% CaF 2 showed the lowest friction coefficient of ∼ 0.29, and both the coating and counterpart had low wear rates. This improvement was primarily attributed to the brittle-to-ductile transition of CaF 2 at high temperatures and the formation of new lubricants. Adhesive wear, oxidative wear, and delamination were the predominant wear mechanisms.
研究领域:
材料科学
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2021
·Vol. 52
·期 5
·3490-3496
·
IF 2.47
Yan Hengwei,Huang Liqiang,Ma Wenhui,Liu Zhanwei,Qin Bo
The NaF-KF-AlF 3 -based electrolyte is a promising low-temperature electrolyte for aluminum reduction. The solubility and dissolution rate of alumina in NaF-KF-AlF 3 -LiF-CaF 2 melt with a cryolite ratio (CR) ranging from 1.5 to 1.8 were investigated by the rotating corundum disk method at 1073 K to 1153 K. The effect of the composition and temperature of the melt on the solubility and dissolution rate of alumina were discussed. The results show that the solubility and dissolution rate of alumina in the melt decrease with the increase of LiF and CaF 2 content, and the effect of LiF on the alumina solubility is greater than that of CaF 2 . The decrease of the CR and temperature lead to a marked reduction of the alumina solubility and alumina dissolution rate. The dissolution rate of alumina depends on the dissolution rate in the first 5 minutes. The alumina dissolution is a zero-order reaction in the first 5 minutes, and a first-order reaction in the next 30 minutes.
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 ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Yuebo Li,Haina Qi,Yunrui Xie,Liu Yang,Wensheng Yu,Qianli Ma,Xiangting Dong,Dan Li,Guixia Liu,Jinxian Wang
CaF 2 :Eu 2+/3+ one-dimensional nanostructures including nanofibers , hollow nanofibers and nanobelts are respectively constructed via a newly-proposed technique of high-efficient combination of electrospinning with bi-crucible fluorinating technique. The diameters of CaF 2 :Eu 2+/3+ nanofibers and hollow nanofibers are respectively 328 ± 2 nm and 290 ± 5 nm, and the width and thickness of nanobelts are 1.07 ± 0.013 μm and 150 nm, respectively. Under the excitation of 276-nm or 320-nm ultraviolet light, CaF 2 :Eu 2+/3+ nanostructures exhibit characteristic emission peaks at 385 nm (purple) and 615 nm (red) assigned to 4f 6 5 d 1 (t 2g )→ 8 S 7/2 energy levels transition of Eu 2+ ions and 5 D 0 → 7 F 2 energy levels transitions of Eu 3+ ions, respectively. XPS data further confirm the coexistence and proportion of Eu 2+ and Eu 3+ in the samples. CaF 2 :9%Eu 2+/3+ nanofibers possess the highest luminescent intensity. White-emitting and color-tunable photoluminescence performance of CaF 2 :Eu 2+/3+ nanostructures are realized by regulating the proportion of Eu 2+ to Eu 3+ ions, and luminescence mechanism is also proposed. Further, it is satisfactorily found that the proportion of Eu 2+ to Eu 3+ ions can be modulated by adjusting the Eu-doped concentration and calcination temperature. The detailed formation mechanisms of CaF 2 :Eu 2+/3+ one-dimensional nanostructures are advanced, and the neoteric fabrication technique is successfully established. This design conception and construction strategy can provide some guidance for fabricating other one-dimensional nanostructures.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2024
·Vol. 55
·期 5
·3995-4000
·
IF 2.4
Chen Angran,Zhang Yanyun,Coetsee Theresa,Kaldre Imants,Wang Cong
EH36-shipbuilding steel has been welded by CaF 2 -ZrO 2 fluxes with designed ZrO 2 additions. Possible chemical and electrochemical reactions have been postulated to analyze alloying element transfer behaviors. The decomposition of ZrO 2 during SAW has been validated by applying the gas–slag–metal equilibrium model and the O supply capacity of ZrO 2 has been quantified. For the entire compositional range, O content has been controlled within a well-maintained range from 220 to 400 ppm, and the transferred quantity of Zr content reaches to the maximum value of 120 ppm. It is further demonstrated that ZrO 2 addition incurs appreciable Si loss within the weld metal.
研究领域:
材料科学
·
焊接工程
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2019
·Vol. 30
·期 15
·155601
·
IF 3.399
Guangqi Hu,Yuqiong Sun,Shuangshuang Wu,Wei Li,Chaofan Hu,Jianle Zhuang,Xuejie Zhang,Bingfu Lei,Yingliang Liu
The shell/core structure of CDs@CaF2 nanocomposites (CCNCs) were prepared by assembling fluorescent carbon dots (CDs) inside the inorganic CaF2 substrates using co-precipitation interaction. CDs endow CaF2 with properties of good UV-absorbing behavior and efficient blue light emission instead of rare-earth such as Eu that is expensive and susceptible to polluting the environment during the mining process. Due to the nanometer size and surface effect of nano CaF2, and the approximate refractive index between CaF2 and polyethylene (PE), CCNC/PE film exhibits better elongation at the break than pure PE film while maintaining high transparency and visible light transmittance. Simultaneously, the CCNC/PE film was experimentally demonstrated to have outstanding performance of anti-UV and blue light conversion, which shows that CCNCs can be a novel and promising multifunctional additive applied in polymers especially for greenhouse film.
研究领域:
材料科学
·
纳米技术
·
聚合物科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Zihe Li,Jian Sun,Xu Zhang,Jingde Zhang,Guifang Han
Mullite-bonded SiC porous ceramics are of potential in hot gas infiltration while the insufficient mechanical performance limits its application. In-situ mullite whisker reinforcement is a potential solution but the formation temperature mismatch between mullite whisker and bonding layer is a challenge. In that case, mullite whiskers massively form ahead of the bonding layer excessively consuming alumina leading to poor bonding layers between SiC particles and thus, the mechanical performance. Herein, the mismatch was solved by using CaF 2 as a temperature-controlled reaction switch. As a result, both the bonding layer and whisker synchronously formed. The material showed significant reinforcement effects, and exhibited a flexural strength of 124.8 MPa and a fracture toughness of 1.53 MPa·m 1/2 with an open porosity of 36.6 vol%, realizing a breakthrough in the mechanical performance. Interestingly, an increase in oxygen vacancy concentration with the sintering temperature was first reported, which may benefit the whisker growth.
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
危险品化学品经营许可证（带存储）