JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·
IF 3.5
Le Fu,Wenjun Yu,Bohan Wang,Ying Deng
Extensive efforts have been devoted to investigate the distribution of dopants in ceramics. However, one critical question remained barely explored, which is the redistribution of dopants between amorphous and crystalline phases during fast sintering of ceramics. Here we address this gap by observing the redistribution of five selected dopants (Y, Ce, Yb, Hf, and Ta) in ZrO 2 –SiO 2 nanoceramics during sintering. We designed two groups of experiments: In group one, dual-phase amorphous particles were sintered with multicomponent crystalline ones. The former particles were ZrO 2 –SiO 2 glass, whereas the latter ones consisted of ZrO 2 solid-solution nanocrystallites (SSNCs) embedded in an oxide glass containing Zr, Si, Y, Ce, Hf, Yb, and Ta. In group two, dual-phase crystalline particles were sintered with multicomponent amorphous ones. The former particles were composed of ZrO 2 nanocrystallites (NCs) embedded in an amorphous SiO 2 matrix, whereas the latter ones were oxide glass containing Zr, Si, Y , Ce, Hf, Yb, and Ta. Redistribution of the dopants from the glass to ZrO 2 NCs occurred in the two groups, that is, the five dopants migrated from the glass matrix into the ZrO 2 NCs, forming ZrO 2 SSNCs. The redistribution of the dopants not only increased the configuration entropy of the ZrO 2 NCs but also benefited the network structure integrity of SiO 2 glass. The dopant redistribution process was driven by the minimization of the studied material's free energy. The reported results are important for understanding the redistribution behaviors of dopants and are expected to provide new insights to design new ceramics via the multielement co-doping strategy.
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
Materials
·
2021
·Vol. 14
·期 9
·2123
·
IF 3.623
Ming Liu,Caochuang Wang,Pengcheng Li,Liang Cheng,Yongming Hu,Yao Xiong,Shishang Guo,Haoshuang Gu,Wanping Chen
Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.
研究领域:
材料科学
·
传感器技术
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Yutong Zhang,Zhangyi Huang,Jianqi Qi,Zhe Tang,Lang Wu,Kuibao Zhang,Tiecheng Lu
In this work, 0.5TRPO•0.5Gd 2 Zr 2 O 7 ceramic with an average grain size of only ∼15 nm was prepared by a high pressure (5 GPa/520 °C) sintering method. Phase evolutions and microstructure changes of the as-fabricated super nano and micron-grained ceramics under a high-dose displacement damage induced by 300 keV Kr 2+ ions were investigated. The results show that the super nano-grained ceramic has low degree of amorphization , obvious grain growth (2–3 times in grain size) and big Kr bubbles (10–68 nm) formation after irradiation. The micron-grained ceramic was severely amorphized after irradiation and many microcracks were formed parallel to its surface. The formation mechanism of Kr bubbles in the super nano-grained ceramic is on account of grain boundary diffusion and migration induced by the accumulation of the injecting Kr ions and irradiation defects. Nevertheless, microcracks formed in the micron-grained sample are caused by the accumulation of Kr atoms.
研究领域:
材料科学
·
核物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Xiyue He,Bijun Fang,Shuai Zhang,Xiaolong Lu,Jianning Ding
Nanoscale [(Ba 0.85 Ca 0.15 ) 0.995 Nd 0.005 ](Ti 0.9 Hf 0.1 )O 3 (Nd-BCTH) ceramics were prepared via the hydrothermal method , and the effects of sintering temperature and holding time on the phase structure, micromorphology, electrical and optical properties of the Nd-BCTH ceramics were explored. All the Nd-BCTH ceramics present rather pure perovskite structure with composition approaching rhombohedral phase around the morphotropic phase boundary (MPB) region. The highest relative density is obtained for the sample sintered at 1220 °C for 10 h. The existence of Ba 2+ , Ca 2+ , Ti 4+ , Hf 4+ and Nd 3+ is confirmed and the elements distribute rather uniformly detected by X-ray photoelectron spectrometer (XPS) and energy dispersive X-ray (EDX) analysis. The ceramics present nanoscale grain size, which tends to increase with the increase of sintering temperature and holding time, and significantly affects dielectric constant and Curie temperature . Very thin and narrow ferroelectric hysteresis loops are observed, where a considerable energy storage density (173.88 mJ/cm 3 ) and high energy storage efficiency (80.68%) are obtained at low electric field. The increase of sintering temperature and holding time induces a red shift at 400 nm absorption edge and a blue shift at 300 nm absorption edge in the Nd-BCTH ceramics, and all ceramics have a maximum absorption value at around 260 nm. Under the excitation of 269 nm light, the Nd-BCTH ceramics show the strongest fluorescence peak at 473 nm, corresponding to the 4 G 3/2 → 4 I 9/2 transition, emitting indigo blue fluorescence. When the ambient temperature is above 400 °C, grains conduction dominates the conductive mechanism in the nano-sized Nd-BCTH ceramics. Such conduction can be attributed to oxygen vacancies caused due to the evaporation of alkaline-earth metals during high temperature sintering, and show typically thermally excited relaxation process.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
THIN SOLID FILMS
·
2022
·
IF 2.358
Yahui He,Shihong Zhang,Yi He,Hongjie Li,Yi Fan,Yihan Zhang,Yuxin Xiang,Teng He,Ruxia Song,Bo Liu,Zhifei Zhang
Zirconium carbide (ZrC) nano-ceramic particles were embedded in the nickel-phosphorus (Ni-P) nanocomposite coating on the surface of N80 steel through electroless deposition strategy. The addition of ZrC can significantly affect the surface morphology, microstructure, wear resistance and corrosion resistance of the coating. Compared with pure Ni-P coating, the average friction coefficient of Ni-P/ZrC (1 g·L −1 ) composite coating decreased from 0.510 to 0.224, and the specific wear rate is reduced from 1.31 × 10 −5 mm 3 ·m −1 ·N −1 to 2.81 × 10 − 6 mm 3 ·m −1 ·N −1 . In terms of improving the corrosion resistance of the coating, Ni-P/ZrC (1 g·L −1 ) composite coating shows a lower corrosion tendency and a higher electrochemical impedance, and its corrosion rate (4.54 × 10 −3 mm·a −1 ) is one order of magnitude lower than Ni-P coating (5.08 × 10 −2 mm·a −1 ). In addition, the long-term corrosion experiments of the samples show that the composite coating has a longer protective effect on the substrate. Through the analysis of the corrosion morphology, it is found that the improvement of the corrosion resistance of the coating is due to the addition of ZrC, which reduces the surface defects of the coating. At the same time, the labyrinth effect formed between ZrC and the coating can also slow down the corrosion rate.
研究领域:
材料科学
·
表面工程
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2018
·
IF 4.229
Sheng Zhu,Pengcheng Li,Guitai Wu,Zhenyu Li,Pei Wu,Yongming Hu,Haoshuang Gu,Wanping Chen
Two kinds of Pt SnO 2 composite nanoceramics have been prepared using SnO 2 nanoparticles and SnO 2 agglomerate powder separately. One is of a relatively uniform and porous microstructure with a specific surface area of 8.1 m 2 /g, and the other is of a rather non-uniform microstructure with large SnO 2 agglomerates and crack-like pores and a specific surface area of 6.4 m 2 /g. While the samples of uniform microstructure typically show a sensitivity of 150 to 1% H 2 – 20% O 2 – N 2 in air of 50% relative humidity (RH) at room temperature , those of non-uniform microstructure surprisingly show much higher sensitivities of 850 and 450 in air of 50% and 70% RH, respectively, to the same concentration of hydrogen. The influence of humidity on the samples has been further studied and a much higher humidity tolerance has been revealed for those samples of non-uniform microstructure. All these results demonstrate a clear and unexpected advantage of a non-uniform microstructure over a uniform one in humidity tolerance for room-temperature hydrogen-sensitive Pt SnO 2 composite nanoceramics.
研究领域:
材料科学
·
传感器技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Jiaochun Zheng,Mao Deng,Yang Shi,Zhangyi Huang,Haomin Wang
The cold sintering process, a novel technique for low-temperature ceramic processing , effectively removes interparticle pores via dissolution and re-precipitation. However, it often triggers grain growth, especially in nanocrystalline ceramics. To address this issue, the present study proposed an innovative two-step cold sintering process with an initial step at 1.5 GPa/RT (room temperature) for 10 min, followed by a subsequent step at 300 MPa/250 °C for 45 min. This method yields ZnO nanocrystalline ceramics with 97.5 % relative density and a 39 nm average grain size (from 30 nm powder). The initial high-pressure step significantly enhances the pressure gradient and particle solubility, leading to very high supersaturation and the occurrence of homogenous nucleation during pressure release. Subsequently, the formation of the crystal nuclei in the interparticle voids can dramatically improve the density of the compact by the additional pore filling and avoid recrystallization-induced grain growth during the second-step cold sintering process.
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
SCRIPTA MATERIALIA
·
2021
·
IF 5.611
Hongye Wang,Minghe Cao,Tenglong Mao,Jiqing Fu,Wengao Pan,Hua Hao,Zhonghua Yao,Hanxing Liu
Nanoceramics have a wide application in dielectric field due to their excellent dielectric properties .However, it is extremely difficult to fabricate densified BaTiO 3 with nanometer scale crystalline. In this study, nanoscaleBaTiO 3 ceramics are successfully fabricated by deposition of a FeO layer onto BaTiO 3 nanoparticle , and the structure and dielectric behavior of the BaTiO 3 @FeO nanoceramics are systematically investigated. The multilayer structure including 1) an inner tetragonal core, 2) a gradient lattice strain layer and 3) a surface insulating layer makes the dielectric constant peak tend to be rounded and broadened. Consequently, an excellent temperature/frequency stability met the X7R requirements and accompanied by the low dielectric loss are achieved in the BaTiO 3 @FeO nanoceramics.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 8
·5461-5471
·
IF 4.186
Hongli Hu,Hangyu Zhong,Bo-xing Zhang
As applications of porous ceramic materials have gradually expanded, the novel technologies for the fabrication of porous ceramic materials with a delicate and controllable structure are still attractive. In this work, three types of porous monolithic ceramic materials, including Al 2 O 3 –SiO 2 , TiO 2 , and SiC, have been fabricated by thermally impacted and non-solvent-induced phase separations in blends of cellulose acetate and ceramic nanoparticles. These materials possessed three-dimensional interconnected porous structures with low densities, high porosities, and hierarchical pores ranging from 5 nm to 6 μm. The relationships between microstructures and phase separations were systematically investigated. Furthermore, electromagnetic shielding effectiveness of 20 dB from 5 to 18 GHz in porous SiC materials has been achieved, revealing that those materials have potential applications in the electromagnetic shielding. This work provides a powerful and general approach to fabricate porous monolithic ceramic materials with a wide range of various ceramic nanoparticles.
研究领域:
材料科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Advanced Science
·
2019
·Vol. 6
·期 17
·1901096
·
IF 15.804
Shaofei Wen,Yunpeng Wang,Bijiao Lan,Weida Zhang,Zhuo Shi,Shichao Lv,Yujun Zhao,Jianrong Qiu,Shifeng Zhou
Transparent nanoceramics embedded with highly dense crystalline domains are promising for applications in missile guidance, infrared night vision, and laser and nuclear radiation detection. Unfortunately, current nanoceramics are strictly constrained by the stringent construction procedures such as super-high pressure and containerless processing. Here, a pressureless crystallization engineering strategy in glass for elaboration of transparent nanoceramics and fibers is proposed and experimentally demonstrated. By intentional creation of a sharp contrast between nucleation and growth rates, the crystal growth rate during glass crystallization can be significantly suppressed. Importantly, this unique phase-transition habit enables the achievement of transparent nanoceramics and even smooth fibers with extremely tiny crystalline size (≈20 nm) and high crystallinity (≈97%) under atmospheric pressure. This allows the generation of an attractive nonlinear optical response such as dynamic optical filtering and luminescence in the mid-infrared waveband of 4300–4950 nm. These findings highlight that the strategy to switch the phase-transition habit of glass into the unconventional crystallization regime may provide new opportunities for the creation of next-generation nanoceramics and fibers.
研究领域:
材料科学
·
无机非金属材料
·
光学功能材料
·
纳米陶瓷
·
玻璃物理
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Qing Yuan,Liping Yan,Yi He,Shijun Xu,Yi Sun,Han Liu,Xiangshan Hou,Huilian Zhou,Xianmin Gong
In this paper, Ni-B alloy coatings were prepared by electroless deposition, similarly, Ni-B/TiC composite coatings with TiC nanoceramic particles as the reinforcing phase were also prepared. On this basis, the composite coating was superhydrophobically modified using hexadecylmethoxysilane (HDTMS) to obtain HDTMS-modified superhydrophobic Ni-B/TiC composite coating (HDTMS* Ni-B/TiC). The hardness of the superhydrophobic coating is up to 954.9 HV, and the wettability test shows that the superhydrophobic composite coating has a water contact angle of 151.2°, and the rolling angle less than 10°. Furthermore, which maintains good non-wettability to several common household stains, in addition to good self-cleaning performance to common household dust. Electrochemical tests show that the corrosion inhibition rate of HDTMS*Ni-B/TiC superhydrophobic composite coatings reach 99.67 % and an impedance value of 3.107 × 10 5 Ω·cm −2 in 3.5 wt% NaCl solution at room temperature. Overall, the prepared superhydrophobic composite coatings have good hydrophobicity, corrosion resistance, and high hardness, which are of extensive research value.
研究领域:
材料科学
·
表面工程
·
腐蚀与防护
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2021
·
IF 5.234
Yang Wang,Qiang Liu,Biao Zhang,Haoqian Zhang,Yicheng Jin,Zhaoxin Zhong,Jian Ye,Yuhan Ren,Feng Ye,Wen Wang
In this study, the researchers constructed nacre-inspired 2024Al/B 4 C composites with a lamellar-interpenetrated structure using pressured infiltration of alloy melt into freeze-cast B 4 C scaffolds, and investigated their dynamic and ballistic properties. The defects such as pores or cracks were hardly observed, and a few intermetallic compounds (IMCs) were contained within the alloy matrix. Because of strain-rate hardening and alloy matrix melting, the dynamic compressive strength and strain were greater than quasi-static ones. The dynamic response could be interpreted by a mixture rule according to B 4 C volume fraction, and by main fracture phenomena such as cracking of B 4 C and IMCs, alloy matrix deformation, and interfacial debonding. After the ballistic test, the nacre-like composites achieved enhanced impact resistance compared to conventional Al/B 4 C materials, while maintaining integrity rather than breaking destructively as monolithic Al/B 4 C composites did, which derived from multiple energy absorption mechanisms including crack deflection, ductile-ligament bridging, and pull-out behavior. This work opens a promising new avenue for the development of advanced armor systems.
研究领域:
材料科学
·
力学
✓ 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）