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Low-temperature Rapid synthesis of Ultrafine Hafnium Carbide Ceramic Powders

Journal of Wuhan University of technology(materials Science) 2018年第4期33卷 843-848页

作者：吴洁王为民 LIU Chun State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan Universi(y of TechnologyWuhan 430070China

Nano hafnium carbide（HfC） powders were synthesized by sol-gel combining hightemperature rapid heat treatment process using citric acid and hafnium tetrachloride as the raw materials. The effects of ball milling treatment on the phase and morphology of pyrolysis products（HfO_2-C） and final HfC product were investigated and the influences of heat treatment temperature and holding time on the structure and properties of the synthesized hafnium carbide powders were also studied. The experimental results showed that the HfO_2-C powders with good uniformity and small particle size were prepared by controlling the milling time. Pure HfC powders with an average particle size of 500 nm were obtained at 1 700 ℃ with a holding time of 3 min, and the oxygen content was about 0.69 wt%, lower than that of the hafnium carbide powders prepared by SPS（0.97%）.

关键词： hafnium carbides sol-gel ball milling high temperature heat treatment

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One-pot synthesis of Bio-inspired Layered materials of 3D Graphene Network/Calcium Carbonate

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Journal of Wuhan University of technology(materials Science) 2017年第4期32卷 795-799页

作者：张晶 YAO Bin PING Hang YU Hongjian ZHANG Fan ZHANG Jinyong WANG Yucheng WANG Hao WANG Weimin 傅正义 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

A bio-inspired layered material of reduced graphene oxide（RGOs） and calcium carbonate was synthesized via a one-pot strategy in DMF/H2O mixed solvent. The experimental results show that the product is a layered material of wrinkled RGOs networks and micron-sized calcium carbonate particles with uniform granular diameter and homogeneous morphology, which are distributed between the layered gallery of the graphene scaffold. The polymorph and the morphology of the in-situ produced calcium carbonate particles can be manipulated by simply changing the temperature scheme. Besides, the graphene oxide was reduced to a certain extent, and the hierarchical wrinkles were generated in the RGOs layer by the in-situ formation of the calcium carbonate particles. This work provides a facile and controllab.e strategy for synthesizing layered material of RGOs and carbonates, and also presents a platform for making three-dimensional porous wrinkled RGOs networks.

关键词： bio-inspired layered structure one-pot synthesis graphene calcium carbonate

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Carbon-supported and nanosheet-assembled vanadium oxide microspheres for stable lithium-ion battery anodes

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Nano Research 2016年第1期9卷 128-138页

作者： Chaojiang Niu Meng Huang Peiyao Wang Jiashen Meng Xiong Liu Xuanpeng Wang Kangning Zhao Yang Yu Yuzhu Wu Chao Lin Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

Naturally abundant transition metal oxides with high theoretical capacity have attracted more attention than commercial graphite for use as anodes in lithium-ion batteries. Lithium-ion battery electrodes that exhibit excellent electrochemical performance can be efficiently achieved via three-dimensional （3D） architectures decorated with conductive polymers and carbon. As such, we developed 3D carbon-supported amorphous vanadium oxide microspheres and crystalline V203 microspheres via a facile solvothermal method. Both samples were assembled with ultrathin nanosheets, which consisted of uniformly distributed vanadium oxides and carbon. The formation processes were clearly revealed through a series of time-dependent experiments. These microspheres have numerous active reaction sites, high electronic conductivity, and excellent structural stability, which are all far superior to those of other lithium-ion battery anodes. More importantly, 95% of the second-cycle discharge capacity was retained after the amorphous microspheres were subjected to 7,000 cycles at a high rate of 2,000 mA/g. The crystalline microspheres also exhibited a high-rate and long-life performance, as evidenced by a 98% retention of the second-cycle discharge capacity after 9,000 cycles at a rate of 2,000 mA/g. Therefore, this facile solvothermal method as well as unique carbon-supported and nanosheet-assembled microspheres have significant potential for the synthesis of and use in, respectively, lithium-ion batteries.

关键词： vanadium oxide microspheres amorphous lithium-ion battery anodes

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Novel MOF shell-derived surface modification of Li-rich layered oxide cathode for enhanced lithium storage

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Science Bulletin 2018年第1期63卷 46-53页

作者： Zhitong Xiao Jiashen Meng Qi Li Xuanpeng Wang Meng Huang Ziang Liu Chunhua Han Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Materials Science and Engineering Wuhan University of Technology Department of Chemistry University of California

Li-rich layered oxide materials have attracted increasing attention because of their high specific capacity(>250 mAh g^(-1)). However, these materials typically suffer from poor cycling stability and low rate performance. Herein, we propose a facile and novel metal-organic-framework(MOF) shell-derived surface modification strategy to construct NiCo nanodots decorated(~5 nm in diameter) carbon-confined Li_(1.2)Mn_(0.54) Ni_(0.13)Co_(0.13)O_2 nanoparticles(LLO@C&NiCo). The MOF shell is firstly formed on the surface of as-prepared Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_2 nanoparticles via low-pressure vapor superassembly and then is in situ converted to the NiCo nanodots decorated carbon shell after subsequent controlled *** obtained LLO@C&NiCo cathode exhibits enhanced cycling and rate capability with a capacity retention of 95% after 100 cycles at 0.4 C and a high capacity of 159 mAh g^(-1) at 5 C, respectively, compared with those of LLO(75% and 105 mAh g^(-1)). The electrochemical impedance spectroscopy and selected area electron diffraction analyses after cycling demonstrate that the thin C&NiCo shell can endow LLO with high electronic conductivity and structural stability, indicating the undesired formation of the spinel phase initiated from the particle surface is efficiently suppressed. Therefore, this presented strategy may open a new avenue on the design of high-performance electrode materials for energy storage.

关键词： Surface modification MOF shell Li-rich layered oxide Lithium-ion battery

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Research on Ultrafine WC-10Co Cemented Carbide with High Propertie

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Journal of Wuhan University of technology(materials Science) 2006年第4期21卷 154-157页

作者：史晓亮 State Key Laboratory of Advanced Technology for Materials Synthesis & Processing Wuhan University of Technology Wuhan 430070 China

WC- 10Co nanocomposite powder produced by spray pyrolysis-continuoas reduction and carbonization technology was used, and the vacuum sinteriag plus sinterhip process was cdopted to prepare ultrafine WCCo cemented carbide. The microstructure, grain size, porosity, density, Rockwell A hardness （ HRA ）, transverse rupture strength （ TRS ） , saturated magnetization and coercivity force were studied. The experimental results show that average grain size of the sample prepared by vacuum sintering plas sinterhip technology was about 420 nm, transverse rupture strength was more than 3460 MPa, and Rockwell A hardness of sintered specimen was more than 92.5. Ultrafine WC- 10Co cemented carbide with high strength and high hardness is obtained.

关键词： WC- Co nanocomposite powder cemented carbide vacuum sinteriag sinterhip

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Thermoelectric properties of phase separated Ti substituted Zr0.75Hf0.25NiSn0.985Sb0.015 half-Heuslers

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Progress in Natural Science:materials International 2020年第1期30卷 74-79页

作者： Rizwan Akram Yonggao Yan Mozaffar Hussain Xiaoyu She Xinfeng Tang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Department of Physics Air University

Sb is a very effective dopant for ZrNiSn based half-Heusler *** effect of Ti substitution on Zr0.75Hf0.25NiSn0.985Sb0.015half-Heusler（HH） semiconductor alloys has been investigated to explore the structural modifications and composition ***0.25Zr0.75-xNiSn0.985Sb0.015（x=0,0.15,0.30,0.45） alloys were synthesized by induction melting.A set of samples was also annealed for comparative *** samples were then sintered using plasma activated sintering（PAS） *** results confirmed the existence of ZrNiSn type HH *** electron（BSE） images showed phase separations in the *** substitution improved the carrier concentration and electrical conductivity of the ***,thermal conductivity was also significantly reduced due to the enhanced phonon ***,a ZT value of 1.11 at 873 K was obtained for 30% Ti substituted（annealed） sample.

关键词： Half-Heuslers Doping Sintering Thermoelectric Mobility

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Conformation of Organic Chain in Phase Transition of Hybrid(Cl2H25NH3)2MnCl4

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武汉理工大学学报（材料科学版）（英文版） 2008年第4期23卷 490-494页

作者： GUO Liling SUN Yubing MEI Ao DAI Yadong LIU Hanxing State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

The structural change in phase transition of hybrid(C12H25NH3)2MnCl4 was *** temperature and the structures of the phase transition is investigated by thermal gravimetry(TG)and differential scanning calorimetry(DSC),infrared spectrum(IR)and X-ray diffraction(XRD).The results suggest that the phase transition is reversible and the structural change arises from the conformation change of the organic *** interlayer distance increases when the hybrid transforms from low temperature phase to high temperature *** is explained by the diffusion of gauche-bond along the organic chains and they move away from each other when the phase transition *** the experimental data with theoretical calculation,we propose that organic chain of the hybrid in high temperature phase is the conformation of gauche-bond alternating with trans bond(noted as GTG'TGTG'TGTG'T).

关键词： organic-inorganic hybrid phase transition interlayer distance conformation

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Eco-friendly high-performance silicide thermoelectric materials

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National Science Review 2017年第4期4卷 611-626页

作者： Wei Liu Kang Yin Qingjie Zhang Ctirad Uher Xinfeng Tang State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Department of Physics University of Michigan

Silicide-based thermoelectrics are examples of cost-efficient and environmentally friendly new energy materials, which can be used for power-generation applications in the range of 500–800 K. We review the research focusing on the exploration of n-type Mg2IV-based solid solutions(IV = Si, Ge and Sn) and summarize the most prominent discoveries achieved so far in their studies. Owing to their superior performance compared to other silicides, including p-type Mg2IV, higher manganese silicides(HMS) are commonly considered as a suitable p-type material to be used in thermoelectric modules in conjunction with n-type Mg2IV-based solid solutions for mid-temperature power-generation applications. We describe the strategies used to improve the thermal and electronic transport properties of n-type Mg2IV-based solid solutions and mention some key features of HMS. We also point out the importance of mechanical properties and thermal stability of this family of materials and offer perspectives on the future research work to further improve their performance.

关键词： silicides band convergence carrier doping composition manipulation mechanical properties thermal stability

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The Densification of Cu/Ti System by Spark Plasma Sintering

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Journal of Wuhan University of technology(materials Science) 2005年第2期20卷 83-85页

作者：张金咏 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

In order to unclose the dynamics of SPS densification, a special sintering sample (Cu/Ti wires compact) was designed. Characters of the shrinkage rates during sintering process and microstructures of products fabricated by the spark plasma sintering(SPS) and hot-press sintering were investigated. The experimental results reveal that a higher temperature field is formed at the connected area and conductive net of the compact. These high-temperature parts deformed more easily than other parts, which is believed to be the main cause of SPS fast densification, according to a hard-core and soft-hell material model.

关键词： spark plasma sintering (SPS) densification modeling

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Effect of Y(Yttrium) Filling Fraction on Thermoelectric Properties of p-type Y_yFe_xCo_(4-x)Sb_(12)

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Journal of Wuhan University of technology(materials Science) 2006年第4期21卷 64-67页

作者：唐新峰 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070China

Yttrium-filled sku, tterudites Yy Fex Co4-x Sb12 （ Y =0- 0. 40 ） were synthesized. The effect of Y filling fraction on thermoelectric properties of Yy Fex Co4-x Sb12 was investigated. All samples showed p-type conduct. The electrical conductivity decreased with increasing filling fraction y. The Seebeck coefficient inreased with increasing temperature. The lattice thermal conductivity decreased with increasing filling fraction y and showed the minimum value at a certain filling fraction y = 0.3. The effect of different filling atoms M（ M： Ba, Ce, Y） on the lattice thermal conductivity of MyFexCo4-xSb12 was discussed. The maximum ZT value of O. 7 was obtained for Y0.06 Fe0.7 Co3.3 Sb12 at 750 K.

关键词： filled sku, tterudite compound filled fraction thermoelectric properties

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