JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 8
·5046-5066
·
IF 3.9
Bo Wang,Delong Cai,Haoyi Wang,Wenhua Zou,Zhihua Yang,Xiaoming Duan,Peigang He,Daxin Li,Wenjiu Duan,Dechang Jia,Hua-Tay Lin,Chao Zhao,Yu Zhou
Boron carbide (B 4 C) ceramic composites with excellent mechanical properties were fabricated by hot-pressing using B 4 C, silicon carbide (SiC), titanium boride (TiB 2 ), and magnesium aluminum silicate (MAS) as raw materials. The influences of SiC and TiB 2 content on the microstructural evolution and mechanical properties of the composites were systematically investigated. The mechanism by which MAS promotes the sintering process of composites was also investigated. MAS exists in composites in the form of amorphous phase. It can effectively remove the oxide layer from the surface of ceramic particles during the high temperature sintering process. The typical values of relative density, hardness, bending strength, and fracture toughness of B 4 C–SiC–TiB 2 composites are 99.6%, 32.61 GPa, 434 MPa, and 6.20 MPa m 1/2 , respectively. Based on the microstructure observations and finite element modeling, the operative toughening mechanism is mainly attributed to the crack deflection along the grain boundary, which results from the residual stress field generated by the thermal expansion mismatch between B 4 C and TiB 2 phase.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xiao-Hui Yang,Yu Wang,Guo-Hua Zhang,Kuo-Chih Chou
Tungsten and molybdenum borides are widely used in ultra-high temperature ceramics (UHTCs) and electrode material. In this research, ultra-fine and ultra-coarse binary borides (WB, W 2 B 5 , MoB, Mo 2 B 5 ) and MoAlB powders were prepared with W/Mo and B 4 C as raw materials and Ca/Al as the decarbonization agent. The feasibility of using Ca and Al as decarburizing agents was assessed by thermodynamic calculations. Meanwhile, the effects of reaction temperature, decarbonization agent type and its additional amount on the phase, morphology and size distribution of the powder products were thoroughly investigated. The results revealed that single phase products with carbon content of less than 1 wt% could be prepared. Moreover, the morphology and particle size of products were significantly affected by the reaction temperature and type of decarburization agent. When using Ca as the decarburizing agent, ultra-fine WB and MoB powders were effectively prepared, probably owing to the fact that W/Mo are essentially insoluble in Ca melt. However, the great solubility of W/Mo in Al makes it easily to synthesize ultra-coarse borides at high temperatures via the dissolution-precipitation mechanism. Additionally, ultra-fine borides particle can also be prepared by lowering the temperature and amount of Al to weak the dissolution-precipitation mechanism.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2022
·
IF 4.804
Yu Wang,Yue-Dong Wu,Guo-Hua Zhang
Molybdenum or tungsten borides are excellent high-temperature ceramics or electrocatalysis materials. In this paper, Mo or W borides were prepared by boronizing Mo or W powder in Al melt with B 4 C as boron source. By thermodynamic calculation, the feasibility of preparing various borides and the stability of borides in Al melt were evaluated. Through high temperature reaction at 1523 K and the following acidic leaching, single phase MoAlB, W 2 B 5 , WB, and W 2 B 5 powders were successfully synthesized. Owing to the decarburizing function of Al melt, C contents of various boride products were below 1 wt%. In addition, the phase transition processes of various products in the synthesis stage were revealed.
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
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Xu Huang,Xuezhang Xiao,Xuancheng Wang,Zhendong Yao,Jiahuan He,Xiulin Fan,Lixin Chen
Li–Mg–B–H reactive hydride composite (RHC) has attracted extensive attention over the past decades for its extremely high hydrogen storage capacity (11.5 wt%). But the sluggish desorption kinetics for the second step dehydrogenation reaction need to be further improved. Herein, short rod-like TMTiO 3 (TM = Co, Ni) bimetallic oxides , which contain two kinds of transition metal elements, were synthesized and introduced into Li–Mg–B–H RHC for the first time. The NiTiO 3 exhibits excellent catalytic effect on the hydrogen desorption kinetic performance of Li–Mg–B–H RHC, and the incubation period for the second step dehydrogenation reaction is eliminated completely by reducing the apparent activation energy for the generation of MgB 2 from 296 kJ/mol to 269 kJ/mol. The NiTiO 3 doped Li–Mg–B–H RHC can desorb about 9.0 wt% H 2 without obvious attenuation of kinetic performance in five cycles. Mechanism analyses reveal that the in-situ generated nano-sized MgNi 3 B 2 and TiB 2 species (∼5 nm) both meet the critical value ( < 10%) of the edge-to-edge matching model (5.77% for MgNi 3 B 2 and 2.22% for TiB 2 ), which play a significant role in supporting the nucleation of MgB 2 . Meanwhile, the extremely fine MgNi 3 B 2 and TiB 2 heterogeneous nucleation sites can inhibit the excessive growth for a single crystal nucleus of MgB 2 . The heterogeneous nucleation and grain refinement mechanisms caused by the novel bimetallic oxide could provide alternative insights into designing an in-situ generated nano-sized catalytic hydrogen storage system with enhanced kinetics and cyclic stability for hydrogen-fueled applications.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Yu Wang,Guo-Hua Zhang,Xin-Bo He,Bai-Jun Yan
This paper provides a new method for preparing refractory metal diboride by reducing refractory metal oxide with Calcium hexaboride (CaB 6 ), which is prepared using B 4 C and calcium as raw materials. For refractory metal powders (M = Ti, Zr, Hf, V, Nb, Ta, Cr) which are expensive and hard to be produced by a simple route, it is more cost-effective to directly use refractory metal oxide to prepare its boride. After reacting at 1473 K for 4 h, CaB 6 and refractory metal oxide could completely react to form MB 2 , CaO and B 2 O 3 . The single-phase product with the particle size of sub-micron was obtained after acidic leaching, filtration and drying. CaB 6 could be used as a universal reducing agent to prepare metal boride.
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
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 105
·期 3
·1954-1966
·
IF 3.784
Yu Wang,Kuo-Chih Chou,Guo-Hua Zhang
Due to strong anti-poisoning ability, good emission stability, high emission current density, lanthanum hexaboride (LaB 6 ) and cerium hexaboride (CeB 6 ) have been maturely applied in electron emission emitter. In this paper, a new manufacturing method for LaB 6 (or CeB 6 ) powder was proposed by using La 2 O 3 (or CeO 2 ), B 4 C, and Al as raw materials. After high-temperature reaction in the range of 1673–1773 K and the following alkaline leaching at 90°C, LaB 6 or CeB 6 powder with particle size of about 10 μm was obtained. Furthermore, by Al metal flux method, the obtained powder was used to manufacture single crystal block with size of several millimeters.
研究领域:
材料科学
·
电子发射材料
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2023
·
IF 7.2
Xinyu Zhu,Yang Li,Xuan Tian,Runde Wang,Shanshan Wang,Huining Wang,Jiemei Yu,Taizhong Huang
Transition metal borides have great potential to be low-cost, high-performance catalysts for novel energies despite the synthesis is rather difficult. In this paper, the reduced graphene oxide (rGO) supported iron boride (Fe 2 B/rGO) based catalysts are synthesized by a facile reduction method. The successful synthesis of Fe 2 B is confirmed by X-ray diffraction, scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photo-electron spectroscopy (XPS) and other tests. HRTEM tests showed that the constructed Fe 2 B was embedded in the rGO, where B played the role of coordination atoms which could regulate the electronic structure of the catalysts and improve the catalytic performance towards oxygen reduction reaction (ORR). The electrochemistry tests showed that the peak current intensity of the Fe 2 B/rGO catalyzed ORR could be reached up to 7.6 mA/cm 2 , which surpassed that of the Pt/C (20 wt%) catalyst. The current intensity can be kept at 82.47% after continuous running 20,000 s, which is higher than the Pt/C catalyst (79.4%). The onset potential reaches up to 0.95 V, which is only 0.06 V lower than that of Pt/C (20 wt%) catalyst. Both RDE and RRDE tests confirmed that the Fe 2 B/rGO catalyzed ORR major happed through 4-electron pathway. The redistributed electron between iron and boron atoms promoted the happening of ORR on Fe 2 B/rGO catalysts. The results of this work provide a novel way to develop high performance transition metal boride based catalysts for ORR.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 22
·7962
·
IF 4.927
Shuhan Chen,Wei Wen,Xue Zhao,Zelang Zhang,Weishuang Li,Yaoyao Zhang,Bojie Li,Lei Zhu
Here, we describe the preparation of copper nanoparticles that are stabilized on a chitosan composite film (CP@Cu). This material could catalyze the 1,6-hydroboration reactions ofp-quinone methides with B2pin2as a boron source under mild conditions. This reaction exhibited very good functional group compatibility, and the organoboron compounds that were formed could easily be converted into corresponding hydroxyl products with good to excellent yields. This newly developed methodology provides an efficient and sequential pathway for the synthesis ofgem-disubstituted methanols.Keywords:copper nanoparticles;chitosan composite film;hydroboration reactions;p-quinone methides;organoboron compounds
研究领域:
化学
·
材料科学
·
有机合成
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 10
·5698-5711
·
IF 3.9
Yao Li,Yu Wang,Guo-Hua Zhang
As the main candidates in the field of ultra-high temperature ceramics, high entropy carbides/borides (HECs/HEBs) have good oxidation resistance properties, high hardness, as well as excellent thermal and electrical conductivities, which are the focused points of research nowadays. In the current study, (Hf,Ta,Zr,Nb,Mo,Ti)C powders were successfully synthesized by a three-step process, including the mixing process of raw oxides and carbon black with spaying Fe(NO 3 ) 3 solution, carbothermal reduction and subsequent calcium posttreatment. For the preparation of (Hf,Ta,Zr,Nb,Mo,Ti)B 2 powders, during the calcium posttreatment process, equal stoichiometric ratio of B 4 C was added for the purpose of boriding reaction. The relevant X-ray diffraction and SEM characterizations indicate the successful preparations of face-centered cubic HECs and hexagonal HEBs. However, slight Mo local segregation was found in the prepared (Hf,Ta,Zr,Nb,Mo,Ti)B 2 powders. The iron generated from Fe(NO 3 ) 3 promotes the solid solution process between monocarbides during the carbothermal reduction process via the dissolution-diffusion-precipitation mechanism. In the calcium posttreatment process, the liquid calcium ensures the boriding reaction take place at a low temperature. In addition, the residual carbon could be combined with calcium to generate CaC 2 which is easy to be removed by acid leaching, and meanwhile, the added Fe could also be finally eliminated to produce pure HEC/HEB powders. The current method does not require the long-time high energy ball milling of raw materials, but only simple and mild mixing is enough. Therefore, such a facile route has a great potential application prospect for industrially preparing high entropy phase powders in a large scale.
研究领域:
材料科学
·
陶瓷
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 9
·1417
·
IF 3.164
Wei Wang,Zufeng Xiao,Chaofan Huang,Kewang Zheng,Yin Luo,Yumin Dong,Zitong Shen,Wei Li,Caiqin Qin
Chitosan microspheres modified by 2-pyridinecarboxaldehyde were prepared and used in the construction of a heterogeneous catalyst loaded with nano-Cu prepared by a reduction reaction. The chemical structure of the catalyst was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). Under mild conditions, such as no ligand at room temperature, the catalyst was successfully applied to catalyze the borylation of α,β-unsaturated receptors in a water-methanol medium, yielding 17%–100% of the corresponding β-hydroxy product. Even after repeated use five times, the catalyst still exhibited excellent catalytic activity.Keywords:chitosan microspheres;copper;organoboron compounds
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Yu Wang,Zhi-Bo Li,Kai-Fei Wang,Guo-Hua Zhang
Tungsten borides are special compounds with potential applications in superhard materials, anti-friction materials, and catalytic materials. In this study, a new synthetic method for tungsten boride is proposed using tungsten (W) and boron carbide (B 4 C) as raw materials. First, the boronization reaction between W and B 4 C was carried out at a high temperature; then, the boronization products were reacted with calcium to generate CaC 2 for decarburization. After acidic leaching of the CaC 2 and Ca, pure tungsten boride could be prepared. By investigating the reaction between different ratios of W and B 4 C, it was found that only pure W 2 B and WB were synthesized in the current method, and W 2 B 5 could react rapidly with Ca to form WB and CaB 6 . However, in the absence of a decarburization treatment after the boronization process, carbon-containing WB (C content = 1.2 wt%) and W 2 B 5 (C content = 3.4 wt%) could also be prepared. In addition, it was concluded that the prepared tungsten boride roughly maintained the morphology and particle size of raw W, and ultra-fine tungsten boride could be synthesized with ultra-fine W powder at a low boronization reaction temperature.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 15
·期 9
·3031
·
IF 3.748
Shijing Zhao,Wenju Zhou,Xiaojun Xiang,Xuyan Cao,Ning Chen,Weifeng Chen,Xiaohui Yu,Bingmin Yan,Huiyang Gou
The precise determination of atomic position of materials is critical for understanding the relationship between structure and properties, especially for compounds with light elements of boron and single or multiple transition metals. In this work, the single crystal X-ray diffraction is employed to analyze the atomic positions of Co2MoB4and Fe2MoB4with a Ta3B4-type structure, and it is found that the lengths of B-B bonds connecting the two zig-zag boron chains are 1.86 Å and 1.87 Å, but previously unreported 1.4 Å. Co and Fe atoms occupy the same crystallographic position in lattice for the doped samples and the valence is close to the metal itself, and Co/Fe K-edge X-ray Absorption Fine Structure(XAFS) spectra of borides with different ratios of Co to Fe are collected to detect the local environment and chemical valence of Co and Fe. Vickers hardness and nano indentation measurements are performed, together with the Density Functional Theory (DFT) calculations. Finally, Co2MoB4possess better thermal stability than Fe2MoB4evaluated by Thermogravimetric Differential Thermal Analysis (TG-DTA) results.Keywords:transition metal boride;hardness;XAFS;thermal stability
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）