Crystals
·
2024
·Vol. 14
·期 5
·452
·
IF 2.4
Sen Yang,Ruiqing Ba,Jingnan Hong,Jing Li,Jingdong Guo,Xinghui He,Hongwei Zhang,Naihe Yi,Weibing Ma
Pure lanthanum hexaboride (LaB6) ceramics were prepared using powders of different grain sizes. The ceramics could reach a relative density of 98.2% at high temperatures and pressures, but had a low flexural strength (136.9 MPa). LaB6ceramics were synthesized using ZrO2-Al2O3-TiO2(ZAT) as sintering additives. The ceramics demonstrate high density and excellent mechanical properties. The hot pressure sintering (HPS) method was utilized in the synthesis of the ceramics. Investigations were conducted on the effects of ZAT content, as well as the effects of the sintering temperature and pressure on the sintering behavior, microstructure, and mechanical and electrical properties of LaB6ceramics. LaB6ceramics fabricated with a ZAT addition of 6 wt.%, at a sintering temperature of 1700 °C, and under a pressure of 50 MPa, exhibited superior sintering and electrical properties, including a relative density of 97%, a conductivity of 7.2 MS/m, a flexural strength of 281.5 MPa, and a Vickers hardness of 21.2 GPa. The LaB6ceramics synthesized in this research exhibit promising potential as electron-emitting cathodes for field emission applications.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
SURFACE & COATINGS TECHNOLOGY
·
2025
·
IF 6.1
Yizhe Lv,Yaoning Sun,Chunming Deng,Xiujuan Fan,Shuangjian Li,Chao Wang,Yaqi Yang,Yuhang Zhang,Chunyan He
Reliable and long-lasting self-lubricating, wear-resistant, and corrosion-resistant ceramic-based coatings are vital for combating coupling damage in marine environments. However, the lack of understanding of marine protective coatings' damage mechanisms has hindered the development of design theories. Therefore, the development of integrated coating preparation techniques and corrosion-wear evolution research are urgently needed. This study introduces carnauba wax into thermally sprayed ceramic coatings via vacuum-hot impregnation, creating a composite coating that exhibits corrosion resistance, wear resistance, and lubrication. Analyzing the electrochemical and tribological performance tests of the composite coatings under various corrosion cycles aims to investigate the protective effect of the coatings and the corrosion/friction evolution patterns. The results indicate that carnauba wax seals micro-nano defects of the coating. Simultaneously, carnauba wax within the coating defects imparts hydrophobic properties (>112°), decreasing seawater interaction with the coating surface. Over a 70-day corrosion testing period, the polarization resistance ( R p ) of the coating reached 2.42 × 10 7 Ω·cm 2 , indicating excellent corrosion resistance. A well-covered lubricating film composed of Al 2 O 3 , ZrO 2 , and carnauba wax was formed in the wear area, with carnauba wax providing a low friction coefficient (<0.2), while nano Al 2 O 3 and ZrO 2 enhance the load-bearing capacity of the lubricating film. Throughout the full corrosion cycle, the coating demonstrates stable and excellent lubricating wear resistance; the wear rate is only 8.58 × 10 −7 mm 3 ∙N −1 ∙m −1 . This research offers new protective strategies for components in marine environments while exploring long-term corrosion-wear evolution of coatings.
研究领域:
材料科学
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表面工程
·
腐蚀与防护
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产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2026
·
IF 5.2
Kuanping Gong,Yongquan Jiang,YongMan Choi
We describe the synthesis and characterization of CaSe 1-x S x :Eu (0 ≤ x ≤ 1) phosphors, uniformly coated with alternating metal oxide layers via a customized fluidized-bed chemical vapor deposition (FB-CVD) technique. Through precise sintering control, the phosphor composition is engineered for tunable red emission under 450 nm blue excitation. First-principles calculations show that Eu 2+ substitution introduces localized Eu 4f states just below the conduction band minimum, enabling efficient blue excitation and red emission, while sulfur substitution enhances lattice stability by increasing intrinsic chalcogenide migration barriers. This energy-level configuration explains efficient Eu 2+ luminescent center activation, yielding intense red emission. Moreover, Se substitution with S increases the anionic migration barrier progressively, consistent with experimental observations of CaSe 1-x S x degradation in humid environments due to Se's inherent instability. However, this moisture susceptibility is markedly reduced via uniform, conformal FB-CVD barrier coatings on individual phosphor particles. Stabilized CaSe 1-x S x phosphors serve as promising components in high-performance warm white light-emitting diodes (W-LEDs), enabling blue-to-red light conversion. As a result, fabricated W-LEDs retain >95% of initial luminance after 1000 h of operation, with negligible chromaticity coordinate shifts.
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DOI
高影响因子
JOURNAL OF THERMAL SPRAY TECHNOLOGY
·
2021
·Vol. 31
·期 1
·269-281
·
IF 2.757
Van Nguyen Tuan,Nguyen Tuan Anh,Pham Ha Thi,Pham Ly Thi,Nguyen Phuong Thi,Dao Thuy Bich,Van Trinh Trung,Vu Duong,Le Quy Thu
A typical structure of thermal spray coatings consisted of molten particles, semi-molten particles, oxides, pores, and cracks. These factors caused the porosity of sprayed coatings, leading to a significant influence on the coating properties, especially their wear-corrosion resistance. In this study, a post-spray sealing treatment of Cr 3 C 2 -NiCr/Al 2 O 3 -TiO 2 plasma-sprayed coatings was carried out, and then, their corrosion properties were evaluated, before and after the treatment. For the sealing process, aluminum phosphate (APP) containing Al 2 O 3 nanoparticles (~10 nm) was used. The permeability of APP into the sprayed coating was analyzed by SEM-EDS. The treatment efficiency for porosity and corrosion resistance of sprayed coatings was evaluated by electrochemical measurements, such as the potentiodynamic polarization and electrochemical impedance spectroscopy. The wear-corrosion resistance of the coating was examined in 3.5 wt.% NaCl circulation solution containing 0.25% SiO 2 particles. The sealing efficiency was evaluated by the percentage of the treated open pores in the coating. The obtained results showed that APP penetrated deeply through the coating and the incorporation of Al 2 O 3 nanoparticles into APP sealant improved the sealing efficiency by 20% of open pores in comparison with the sealant without nano-Al 2 O 3 . The effect of the post-treatment on corrosion protection of the sprayed coating has been discussed.
研究领域:
材料科学
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表面工程
·
腐蚀与防护
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产品关联
DOI
PubMed
高影响因子
DYES AND PIGMENTS
·
2016
·
IF 4.055
M.M. Mikhailov,V.V. Neshchimenko,Chundong Li
This study carried out on the diffuse reflective spectra of zinc oxide modified by Al 2 O 3 , ZrO 2 , SiO 2 , CeO 2 , TiO 2 and Y 2 O 3 nanoparticles . It was established that during the modification are formed the solid solutions between zinc oxide and nanopowder as Al 2 ZnO 4 , ZrZnO 3 , Zn 2 SiO 4 , Ce x Zn (1−х) О y , Zn 2 TiO 4 , Y x Zn (1−x) O y . The diffuse reflection spectra of the modified powders are changed in the UV and visible range with a maximum at 395 nm. This band is determined by the intrinsic point defects in the crystal lattice of ZnO as interstitial zinc ions and zinc vacancy. In the IR region also recorded changes due to the absorption of OH-groups adsorbed on the surface modified zinc oxide.
研究领域:
材料科学
·
光学
·
纳米技术
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 11
·6953-6964
·
IF 4.186
Yuchao Qiu,Junjie Shi,Bin Yu,Changle Hou,Jingjing Dong,Song Li,Yumo Zhai,Jianzhong Li,Changsheng Liu
The recycling of titanium from titania-bearing slag is an important part of the circular economy; however, the yield of titania is restricted due to the lack of fundamental thermodynamic data. In the present work, the equilibrium phase relations of MgO–Al 2 O 3 –TiO 2 system in air at 1600°C have been determined using a high-temperature equilibration-quenching technique followed by X-ray photoelectron spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectrometry, and X-ray diffraction. Ti 4+ was confirmed as the stable valence of titanium, and the rutile and spinel solid solution phases were detected to be coexisting with pseudobrookite solid solution phase, respectively. The formation principles of pseudobrookite and spinel solid solutions were confirmed in view of the corresponding crystal structure and the composition substitution relationship of the oxides at 1600°C. However, great discrepancies were found from the comparison of the present experimental results with the thermodynamic calculations and the literature results, and the present equilibrium phase relations are therefore significant for updating the present titania related thermodynamic database for a superior prediction of the thermodynamic behaviors of relevant process.
研究领域:
材料科学
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冶金工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）