Strted in 1985 Monthly
ISSN 1005-0302
CN 21-1315/TG
Impact factor:2.764

The journal has been awarded the excellent periodical in China, and its articles are covered by SCI, EI, CA, SA, JST, RJ, CSA, MA, EMA, AIA etc., PASCAL web. ISI web of Science,SCOPUS.

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Controlling molecular weight of naphthalenediimide-based polymer acceptor P(NDI2OD-T2) for high performance all-polymer solar cells
Lei Yu, Sun Jianxia, Yuan Jianyu, Gu Jinan, Ding Guanqun, Ma Wanli
J. Mater. Sci. Technol.    2017, 33 (5): 411-417.   DOI: 10.1016/j.jmst.2016.06.028
Abstract   HTML PDF (2058KB)  

A widely-used naphthalenediimide (NDI) based electron acceptor P(NDI2OD-T2) with different number-average molecular weight (Mn) of 38 (N2200L), 56 (N2200M), 102 (N2200H) kDa were successfully prepared. The effect of molecular-weight on the performance of all-polymer solar cells based on Poly(5-(5-(4,8-bis(5-decylthiophen-2-yl)-6-methylbenzo[1,2-b:4,5-b’]dithophen-2-yl)thiophen-2-yl)-6,7-difluoro-8-(5-methylthiophen-2-yl)-2,3-bis(3-(octyloxy)phenyl)quinoxaline) (P2F-DE):N2200 was systematically investigated. The results reveal that N2200 with increased Mn show enhanced intermolecular interactions, resulting in improved light absorption and electron mobility. However, the strong aggregation trend of N2200H can cause unfavorable morphology for exciton dissociation and carrier transport. The blend film using N2200 with moderate Mn actually develops more ideal phase segregation for efficient charge separation and transport, leading to balanced electron/hole mobility and less carrier recombination. Consequently, all-polymer solar cells employing P2F-DE as the electron donor and N2200M as the electron acceptor show the highest efficiency of 4.81%, outperforming those using N2200L (3.07%) and N2200H (3.92%). Thus, the Mn of the polymer acceptor plays an important role in all-polymer solar cells, which allows it to be an effective parameter for the adjustment of the device morphology and efficiency.

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Nitrogen- and Oxygen-Containing Porous Ultrafine Carbon Nanofiber: A Highly Flexible Electrode Material for Supercapacitor
Wei Kai, Kim Kyu-Oh, Song Kyung-Hun, Kang Chang-Yong, Soon Lee Jung, Gopiraman Mayakrishnan, Kim Ick-Soo
J. Mater. Sci. Technol.    2017, 33 (5): 424-431.   DOI: 10.1016/j.jmst.2016.03.014
Abstract   HTML PDF (2847KB)  

Herein, we report a simple and effective preparation of ultrafine CNFs (u-CNFs) with high surface area via electrospinning of two immiscible polymers [polyacrylonitrile (PAN) and poly(methyl methacrylate) (PMMA)] followed by calcination at high temperature in an inert atmosphere. Various electrospinning conditions were optimized in detail. Four different kinds of PAN/PMMA ratios (10/0, 7:3, 5:5 and 3:7) were chosen and found that the PAN/PMMA ratio of 3:7 (PAN/PMMA-3:7) is the optimum one. BET analysis showed the specific surface area of the u-CNFs-3:7 was 467.57 m2/g with an excellent pore volume (1.15 cm3 g-1) and an average pore size (9.48 nm): it is about 25 times higher than the conventional CNFs (c-CNFs). TEM and FE-SEM images confirmed the ultrafine structure of the CNFs with a thinner fiber diameter of ~50 nm. The graphitic nature and atomic arrangement of the u-CNFs were investigated by Raman and XPS analyses. For the supercapacitor application, unlike the common electrode preparation methods, the u-CNFs-3:7 was used without any activation, chemical or mechanical modifications. The u-CNFs-3:7 showed a better specific capacitance of 86 F/g in 1 mol/L H2SO4 when compared to pure CNFs. The excellent physicochemical properties make the u-CNFs-3:7 an alternative choice to the existing CNFs for the supercapacitors.

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Photovoltaic devices employing ternary PbSxTe1-x nanocrystals
Zhu Xiangxiang, Liu Zeke, Shi Guozheng, Gu Jinan, Wang Weiwei, Ma Wanli
J. Mater. Sci. Technol.    2017, 33 (5): 418-423.   DOI: 10.1016/j.jmst.2017.01.018
Abstract   HTML PDF (963KB)  

Colloidal quantum dots (CQDs), especially lead chalcogenide CQDs, are regarded as promising materials for the next generation solar cells, due to their large absorption coefficient, excellent charge transport, and multiple exciton generation effect. We successfully synthesized highly-crystalline, monodispersed, well-alloyed PbSxTe1-x nanocrystals via a one-pot, hot injection reaction method. Energy-filtered transmission electron microscopy suggested that the S and Te anions were uniformly distributed in the alloy nanoparticles. The photovoltaic performance of CQD solar cells based on ternary PbSxTe1-x was reported for the first time. The photovoltaic devices using PbSxTe1-x were more efficient than either the pure PbS or the PbTe based devices. In addition, the PbSxTe1-x based devices showed a significantly improved stability than that of the PbTe based devices.

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White Light Emission Characteristics of Tb3+/Sm3+ Co-Doped Glass Ceramics Containing YPO4 Nanocrystals
Zhang Zhixiong, Zhang Yuepin, Wang Cheng, Feng Zhigang, Zhang Weihuan, Xia Haiping
J. Mater. Sci. Technol.    2017, 33 (5): 432-437.   DOI: 10.1016/j.jmst.2016.10.002
Abstract   HTML PDF (1856KB)  

The Tb3+/Sm3+ single-doped and co-doped glasses and glass ceramics containing YPO4 nanocrystals have been synthesized by melt quenching method. The structural and luminescent properties of these glass specimens were investigated. Under 375 nm wavelength excitation, the emission spectra combined with blue, green and red bands were observed, which achieved the white light emission. Moreover, the energy transfer between Tb3+ and Sm3+ ions was validated by decay lifetime measurement and energy level diagram. The color coordinates (x = 0.333, y = 0.333), correlated color temperature (5595 K) and the color rendering index (Ra = 80.5) indicated that the glass ceramics were considered to be good lighting source. Hence, the YPO4-based Tb3+/Sm3+ co-doped glass ceramics can act as potential matrix materials for white light-emitting diodes under ultraviolet excitation.

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Amorphous Cobalt Boron Alloy@Graphene Oxide Nanocomposites for Pseudocapacitor Applications
Zhang Wei, Du Xiaoli, Tan Yueyue, Hu Jinbo, Li Zhen, Tang Bohejin
J. Mater. Sci. Technol.    2017, 33 (5): 438-443.   DOI: 10.1016/j.jmst.2016.06.012
Abstract   HTML PDF (1477KB)  

Amorphous Co-B alloy nanoparticles grown on graphene sheets were synthesized via a chemical reduction approach and successfully used for an application as a pseudocapacitor. This study aims to improve the capacity and cycling stability of amorphous Co-B alloy nanoparticles grown on conductive graphene sheets. The products were characterized by X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. As electrode materials for pseudocapacitors, the amorphous Co-B alloy grown on graphene oxide (Co-B@GO) exhibits a high specific capacitance of 460 F g-1, which is nearly 1.5 times greater than that of bare Co-B nanoparticles at 1 A g-1. The specific capacitance preserved 84% of the initial capacitance even after 1000 cycles at a scan rate of 10 m V-1, suggesting its promising potential as pseudocapacitor materials.

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Microstructure and mechanical properties of Mg-4.0Zn alloy reinforced by NiO-coated CNTs
Yuan Qiuhong, Zeng Xiaoshu, Wang Yanchun, Luo Lan, Ding Yan, Li Dejiang, Liu Yong
J. Mater. Sci. Technol.    2017, 33 (5): 452-460.   DOI: 10.1016/j.jmst.2016.07.022
Abstract   HTML PDF (5066KB)  

Mg-4.0Zn alloy composite reinforced by NiO-coated CNTs (NiO@CNTs) was synthesized by combining ball-milling and a casting process. The yield strength (YS) and elongation to failure of the composite were dramatically increased by 44.9% and 38.6%, respectively, compared to its alloy counterpart. The significantly enhanced mechanical properties of the as-synthesized composite are mainly ascribed to an improved interfacial bond, grain refinement and good dispersion of CNTs in the matrix via. coating NiO on CNTs. It is shown that the NiO-nanolayer on the CNTs significantly enhances the interfacial bonding strength and effectively prevents the agglomeration of CNTs. NiO@CNTs are, therefore, expected to be a highly sustainable and dispersible reinforcement for magnesium matrix composites with superior performance.

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Morphology-Controlled Synthesis of CeO2 Microstructures and Their Room Temperature Ferromagnetism
Meng Fanming, Fan Zhenghua, Zhang Cheng, Hu Youdi, Guan Tao, Li Aixia
J. Mater. Sci. Technol.    2017, 33 (5): 444-451.   DOI: 10.1016/j.jmst.2016.06.018
Abstract   HTML PDF (3268KB)  

Gear-shape CeO2 microstructures have been synthesized via a facile hydrothermal method with Ce(NO3)3?6H2O as the cerium source, NH4HCO3 as both the precipitator and the carbon source, and cetyltrimethyl ammonium bromide (CTAB) as the surfactant. X-ray diffraction (XRD) inferred that the synthesized CeO2 microstructures exhibited a fluorite structure. The band gap (Eg) of CeO2 samples is larger than that of bulk. X-ray photoelectron spectroscopy (XPS) showed that there are plenty of Ce3+ ions and oxygen vacancies at the surface of CeO2 samples. All the synthesized CeO2 samples exhibited the room temperature ferromagnetism, and the saturation magnetization increases with the increases of lattice parameter and Eg. The room temperature ferromagnetism mechanism of gear-shape CeO2 is mainly attributed to the influence Ce3+ ions.

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In Vivo Study on Degradation Behavior and Histologic Response of Pure Magnesium in Muscles
Chen Shanshan, Tan Lili, Zhang Bingchun, Xia Yonghui, Xu Ke, Yang Ke
J. Mater. Sci. Technol.    2017, 33 (5): 469-474.   DOI: 10.1016/j.jmst.2016.09.011
Abstract   HTML PDF (1842KB)  

When an orthopedics device is implanted into bone injury site, it will contact the soft tissue (skeletal muscle, fascia, ligament etc.) except for bone. Magnesium based biodegradable metals are becoming an important research object in orthopedics due to their bioactivity to promote bone healing. In this study, pure Mg rods with and without chemical conversion coating were implanted into the muscle tissue of rabbits. Implants and their surrounding tissues were taken out for weight loss measurement, cross-sectional scanning electron microscopy observation, elemental distribution analysis and histological examination. The results showed that the chemical conversion coating would increase the in vivo corrosion resistance of pure Mg and decrease the accumulation of calcium (Ca) and phosphorus (P) elements around the implants. For the bare magnesium implant, both Ca and P contents in the surrounding tissues increased at the initial stage of implantation and then decreased at 12 weeks implantation, while for the magnesium with chemical conversion coating, Ca and P contents in the surrounding tissues decreased with the implantation time, but were not significant. The histological results demonstrated that there was no calcification in the muscle tissue with implantation of magnesium for up to 12 weeks. The chemical conversion coating not only increased the in vivo corrosion resistance of pure Mg, but also avoided the depositions of Ca and P in the surrounding tissues, meaning that pure magnesium should be bio-safe when contacting with muscle tissues.

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Plasma electrolytic oxidation of the magnesium alloy MA8 in electrolytes containing TiN nanoparticles
Mashtalyar D.V., Gnedenkov S.V., Sinebryukhov S.L., Imshinetskiy I.M., Puz’ A.V.
J. Mater. Sci. Technol.    2017, 33 (5): 461-468.   DOI: 10.1016/j.jmst.2017.01.021
Abstract   HTML PDF (2756KB)  

The formation of protective multifunctional coatings on magnesium alloy MA8 using plasma electrolytic oxidation (PEO) in an electrolytic system containing nanosized particles of titanium nitride was investigated. Electrochemical and mechanical properties of the obtained layers were examined. It was established that microhardness of the coating with the nanoparticle concentration of 3 g l-1 increased twofold (4.2 ± 0.5 GPa), while wear resistance decreased (4.97 × 10-6 mm3 N-1 m-1), as compared to respective values for the PEO-coating formed in the electrolyte without nanoparticles (2.1 ± 0.3 GPa, 1.12 × 10-5 mm3 N-1 m-1).

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Mechanical Property, Oxidation and Ablation Resistance of C/C-ZrB2-ZrC-SiC Composite Fabricated by Polymer Infiltration and Pyrolysis with Preform of Cf/ZrB2
Huang Dong, Zhang Mingyu, Huang Qizhong, Wang Liping, Tong Kai
J. Mater. Sci. Technol.    2017, 33 (5): 481-486.   DOI: 10.1016/j.jmst.2016.09.003
Abstract   HTML PDF (3317KB)  

C/C-ZrB2-ZrC-SiC composites were fabricated by polymer infiltration and pyrolysis (PIP) with a preform of Cf/ZrB2. The carbon fibers and the resin carbon were coated with ceramic layer after PIP in the composites. The composite presents a pseudo-plastic fracture due to deflection of cracks and pullout of fibers. The composite has a higher bending strength by this method in comparison with the conventional PIP process due to fewer heat treatment cycles. The static oxidation test shows that the mass loss of the composites is no more than 1% after 20 min oxidation at 1100 °C. The “core-shell” structure between ZrC-SiC ceramic and other phases plays a positive role in preventing the inward diffusion of oxygen. The ablation resistance of the C/C-ZrB2-ZrC-SiC composite samples was tested using a plasma generator. After ablation for 120 s, the mass and linear ablation rates of the composites are 4.65 mg cm-2 s-1 and 2.46 μm s-1, respectively. The short carbon layer shows a better ablation resistance than the nonwoven carbon fabric layer after the ceramic coating is peeled off because of its higher ceramic content.

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Effect of Icosahedral Phase on Crystallographic Texture and Mechanical Anisotropy of Mg-4%Li Based Alloys
Li C.Q., Xu D.K., Yu S., Sheng L.Y., Han E.H.
J. Mater. Sci. Technol.    2017, 33 (5): 475-480.   DOI: 10.1016/j.jmst.2016.10.003
Abstract   HTML PDF (4139KB)  

Through investigating and comparing the microstructure and mechanical properties of the as-extruded Mg alloys Mg-4%Li and Mg-4%Li-6%Zn-1.2%Y (in wt%), it demonstrates that although the formation of I-phase (Mg3Zn6Y, icosahedral structure) could weaken the crystallographic texture and improve the mechanical strength, the mechanical anisotropy in terms of strength remains in Mg-4%Li-6%Zn-1.2%Y alloy. Failure analysis indicates that for the Mg-4%Li alloy, the fracture surfaces of the tensile samples tested along transverse direction (TD) contain a large number of plastic dimples, whereas the fracture surface exhibits quasi-cleavage characteristic when tensile samples were tested along extrusion direction (ED). For the Mg-4%Li-6%Zn-1.2%Y alloy, typical ductile fracture surfaces can be observed in both “TD” and “ED” samples. Moreover, due to the zonal distribution of broken I-phase particles, the fracture surface of “TD” samples is characterized by the typical “woody fracture”.

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Joining of Cf/SiBCN composite with two Ni-based brazing fillers and interfacial reactions
Li Wenwen, Chen Bo, Xiong Yi, Xiong Huaping, Cheng Yaoyong, Zou Wenjiang
J. Mater. Sci. Technol.    2017, 33 (5): 487-491.   DOI: 10.1016/j.jmst.2017.01.032
Abstract   HTML PDF (1080KB)  

Cf/SiBCN ceramic composite was joined using Ni-19Cr-10Si (BNi5) and Ni-33Cr-24Pd-3.5Si-0.5B filler alloys at 1170 °C for 10 min. Two kinds of Ni-based filler alloys exhibited good wettability on the Cf/SiBCN composite, with a contact angle of 13° and 4°, respectively. The microstructures of the brazed joints were investigated by electron-probe microanalysis (EPMA), and three-point bend test was conducted for the joints at room temperature. When being brazed with BNi5 filler alloy, no evident reaction layer was observed at the surface of the joined composite, and the joint microstructure was characterized by Ni2Si matrix with scatteringly distributing mixture compounds of Cr23C6, Ni2Si and CrB. While Ni-Cr-Pd(Si,B) brazing alloy was used, a Cr23C6 reaction layer with a thickness of 11 μm was formed at the surface of the base composite. In the central part of the brazed joint, the phases were composed of Ni(Cr,Si) solid solution and complex compounds including Pd2Si, (Ni,Pd)2Si and Ni-B. The strength of Cf/SiBCN joint brazed with BNi5 filler alloy was 62.9 MPa at room temperature, whereas that with Ni-Cr-Pd(Si,B) filler alloy was at the same level.

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Interfacial Structure and Formation Mechanism of Ultrasonic-assisted Brazed Joint of SiC Ceramics with Al-12Si Filler Metals in Air
Chen Xiaoguang, Xie Ruishan, Lai Zhiwei, Liu Lei, Yan Jiuchun, Zou Guisheng
J. Mater. Sci. Technol.    2017, 33 (5): 492-498.   DOI: 10.1016/j.jmst.2016.03.016
Abstract   HTML PDF (1983KB)  

Ultrasonic-assisted brazing of SiC ceramics was performed by filling with an Al-12Si alloy at a low temperature of 620 °C in air. The interfacial characteristics and formation mechanism were investigated. The joint shear strength reached 84-94 MPa using the ultrasonic time of 2-16 s. The fracture morphology showed that the fracture path initiated and propagated in the joint alloy. The thin film of amorphous SiO2 that formed on the SiC surface was non-uniformly decomposed and diffused into the liquid Al-12Si alloy under the cavitation erosion effect of ultrasound. Abnormal isolated blocks of Al2SiO5 compounds formed at the interface between Al-12Si and a thicker SiO2 layer formed during the thermal oxidation treatment of the SiC ceramic. The SiO2 layer on the SiC ceramic did not hinder or impair the wetting and bonding process, and a stronger bond could form between Al-12Si and SiO2 or SiC in ultrasonic-assisted brazing.

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Prediction of Dendrite Orientation and Stray Grain Distribution in Laser Surface-melted Single Crystal Superalloy
Wang Guowei, Liang Jingjing, Zhou Yizhou, Jin Tao, Sun Xiaofeng, Hu Zhuangqi
J. Mater. Sci. Technol.    2017, 33 (5): 499-506.   DOI: 10.1016/j.jmst.2016.05.007
Abstract   HTML PDF (3858KB)  

A vectorization analysis technique for crystal growth and microstructure development in single-crystal weld was developed in our previous work. Based on the vectorization method, crystal growth and stray grain distribution in laser surface remelting of single crystal superalloy CMSX-4 were investigated in combination of simulations with experimental observations. The energy distribution of laser was taken into consideration in this research. The experimental results demonstrate that the simulation model applies well in the prediction of dendrite growth direction. Moreover, the prediction of stray grain distribution works well except for the region of dendrites growing along the [100] direction.

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A high-strength, ductile Al-0.35Sc-0.2Zr alloy with good electrical conductivity strengthened by coherent nanosized-precipitates
Guan Renguo,Shen Yongfeng,Zhao Zhanyong,Wang Xiang
J. Mater. Sci. Technol.    2017, 33 (3): 215-223.  
Abstract   HTML PDF (2391KB)  

Ductility and electrical conductivity of metallic materials are inversely correlated with their strength, resulting in a difficulty of optimizing all three simultaneously. We design an Al-Sc-Zr-based alloy using semisolid extrusion to yield a good trade-off between strength and ductility along with excellent electrical conductivity. The Al-0.35Sc-0.2Zr wire with a diameter of 3?mm exhibited the best combined properties: a tensile strength of 210?±?2?MPa, elongation of 7.6%?±?0.5%, and an electrical conductivity of 34.9?±?0.05?MS/m. The average particle size of nanosized Al3(Sc, Zr) precipitates increased from 6.5?±?0.5?nm to 25.0?±?0.5?nm as the aging time increased from 1?h to 96?h at 380?°C, accompanied by the corresponding volume fraction variation from (6.2?±?0.1)?×?10-4 to (3.7?±?0.1)?×?10-3. As proved by transmission electron microscopy observation, the high strength originates from the effective blockage of dislocation motion by numerous nanosized Al3(Sc, Zr) precipitates whilst both electrical conductivity and ductility remain at a high level due to the coherent precipitates possessing an extremely low electrical resistivity.

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Microstructure Evolution and Mechanical Properties of a SMATed Mg Alloy under In Situ SEM Tensile Testing
Liu Xiaowei,Liu Yong,Jin Bin,Lu Yang,Lu Jian
J. Mater. Sci. Technol.    2017, 33 (3): 224-230.   DOI: 10.1016/j.jmst.2016.11.012.
Abstract   HTML PDF (2932KB)  

Surface mechanical attrition treatment (SMAT) has been recently applied to bulk polycrystalline magnesium (Mg) alloys with gradient grain size distribution from the impact surface to inside matrix, hence effectively improving the alloys' mechanical performances. However, in-depth understanding of their mechanical property enhancement and grain size-dependent fracture mechanism remains unclear. Here, we demonstrated the use of in situ micro-tensile testing inside a high resolution scanning electron microscope (SEM) to characterize the microstructure evolution, in real time, of SMATed Mg alloy AZ31 samples with different grain sizes of ~10?µm (‘coarse-grain sample’) and ~5?µm (‘fine-grain sample’), respectively, and compared the results with those of a raw Mg alloy AZ31. The quantitative tensile tests with in situ SEM imaging clearly showed that fracture of ‘fine-grain sample’ was dominated by intergranular cracks, while both trans-granular and intergranular cracks led to the final failure of the ‘coarse-grain samples’. It is expected that this in situ SEM characterization technique, coupled with quantitative tensile testing method, could be applicable for studying other grain-refined metals/alloys, allowing to optimize their mechanical performances by controlling the grain sizes and their gradient distribution.

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SiO2@C hollow sphere anodes for lithium-ion batteries
Liu Xuelian,Chen Yuxi,Liu Hongbo,Liu Zhi-Quan
J. Mater. Sci. Technol.    2017, 33 (3): 239-245.  
Abstract   HTML PDF (3711KB)  

As anode materials for lithium-ion batteries, SiO2 is of great interest because of its high capacity, low cost and environmental affinity. A facile approach has been developed to fabricate SiO2@C hollow spheres by hydrolysis of tetraethyl orthosilicate (TEOS) to form SiO2 shells on organic sphere templates followed by calcinations in air to remove the templates, and then the SiO2 shells are covered by carbon layers. Electron microscopy investigations confirm hollow structure of the SiO2@C. The SiO2@C hollow spheres with different SiO2 contents display gradual increase in specific capacity with discharge/charge cycling, among which the SiO2@C with SiO2 content of 67?wt% exhibits discharge/charge capacities of 653.4/649.6?mA?h?g-1 over 160 cycles at current density of 0.11?mA?cm-2. The impedance fitting of the electrochemical impedance spectroscopy shows that the SiO2@C with SiO2 content of 67?wt% has the lowest charge transfer resistance, which indicates that the SiO2@C hollow spheres is promising anode candidate for lithium-ion batteries.

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Effects of concurrent grain boundary and surface segregation on the final stage of sintering: the case of Lanthanum doped yttria-stabilized zirconia
Gong M.M.,Dey S.,Wu L.J.,Chang C.H.,Li H.,Castro R.H.R.,Liu F.
J. Mater. Sci. Technol.    2017, 33 (3): 251-260.  
Abstract   HTML PDF (1280KB)  

Dopants play a critical role in tailoring the microstructure during sintering of compacts. These dopants may form solid solution within the bulk, and/or segregate to the grain boundaries (GBs) and the solid-vapor interfaces (free surfaces), each causing a distinct energetic scenario governing mass transports during densification and grain growth. In this work, the forces controlling the dopant distribution, in particular the possibility of concurrent segregation at both surfaces and GBs, are discussed based on the respective enthalpy of segregation. An equation is derived based on the minimum Gibbs energy of the system to determine enthalpy of segregation from experimental interface energy data, and the results applied to depict the role of La as a dopant on the interface energetics of yttria stabilized zirconia during its final stage of sintering. It is shown that La substantially decreases both GB and surface energies (differently) as sintering progresses, dynamically affecting its driving forces, and consequent grain growth and densification in this stage.

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Au nanoparticles decorated graphene/nickel foam nanocomposite for sensitive detection of hydrogen peroxide
Wang Xiaojuan,Guo Xinli,Chen Jian,Ge Chuang,Zhang Hongyi,Liu Yuanyuan,Zhao Li,Zhang Yao,Wang Zengmei,Sun Litao
J. Mater. Sci. Technol.    2017, 33 (3): 246-250.  
Abstract   HTML PDF (1457KB)  

The Au nanoparticles decorated graphene (AuNPs@Gr)/nickel foam (Gr/NiF) nanocomposite (AuNPs@Gr/NiF) was prepared by chemical vapor deposition followed by electrophoretic deposition of AuNPs on Gr/NiF. The morphology, microstructure and sensing performance of the as-prepared AuNPs@Gr/NiF nanocomposite were characterized and measured, respectively by scanning electron microscope, transmission electron microscope, ultraviolet visible spectroscopy and chemical workstation. The as-prepared AuNPs@Gr/NiF nanocomposite was used as the electrode to construct a chemical sensor for the detection of hydrogen peroxide (H2O2). The results showed that the AuNPs distributed homogenously and stably on the surface of Gr/NiF. The chemical sensor exhibits a sensitive and selective performance to the detection of H2O2.

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Giant Rheological Effect of Shear Thickening Suspension Comprising Silica Nanoparticles with No Aggregation
Li Shuangbing,Wang Jixiao,Zhao Song,Cai Wei,Wang Zhi,Wang Shichang
J. Mater. Sci. Technol.    2017, 33 (3): 261-265.  
Abstract   HTML PDF (1614KB)  

The spherical silica particles in narrow size distribution with different diameters of 90?nm, 200?nm, 320?nm and 400?nm were prepared by the modified Stöber method and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The phase composition of particles was characterized by X-ray diffraction. The results indicated that each of the silica particle samples was in amorphous state. The shear thickening fluids (STFs) comprising 53 vol.% of silica particles and 47 vol.% of polyethylene glycol with molecular weight of 200?g mol-1 (PEG200) were prepared and evaluated. The influence of size and size distribution on the critical shear rate and the intensity of shear thickening were analyzed. The STFs prepared by silica nanoparticles with a diameter of 90?nm showed the giant rheological effect with the critical shear rate of 2.51?s-1, the largest viscosity of 45,500?Pa∙s and the yield stress of 181?kPa. The experiments and the analysis results demonstrated that the suspensions prepared by nanoparticles have high intensity of shear thickening.

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In-Situ Chemosynthesis of ZnO Nanoparticles to Endow Wood with Antibacterial and UV-Resistance Properties
Dong Youming,Yan Yutao,Ma Huandi,Zhang Shifeng,Li Jianzhang,Xia Changlei,Q. Shi Sheldon,Cai Liping
J. Mater. Sci. Technol.    2017, 33 (3): 266-270.  
Abstract   HTML PDF (1244KB)  

Hybrid wood materials have attracted considerable attention because they have combined advantages of both wood and inorganic compounds. This work investigated the microstructural morphology, thermal stability, ultraviolet (UV) stability, and antibacterial property of composites made from wood/ZnO hybrid materials through a facile in-situ chemosynthesis methods. The X-ray diffraction (XRD) and thermogravimetric analysis (TGA) results indicated that the synthesized ZnO particles had an average grain size of about 10.8?nm. The scanning electron microscopy (SEM) observations showed that ZnO nanoflowers self-assembled with nanosheets were presented in wood cell lumens and increased with increasing Zn2+ concentrations. ZnO nanoparticles were also generated in the wood cell wall, which was confirmed by the results of energy-dispersive spectroscopy (EDS). The TGA tests also indicated that the thermal stability of wood/ZnO hybrid materials was improved after the formation of ZnO inorganic particles. Finally, the results of antibacterial efficacy tests and UV resistance tests revealed that ZnO nanoparticles showed a promising future as antimicrobial agents against Escherichia coli (E. coli) and UV resistance agents for wood protection.

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Stress-Induced Martensitic Transformation of Zr50Cu25Ni10Co15Nanocrystals Embedded in an Amorphous Matrix
Gao W.H.,Yi X.Y.,Meng X.L.,Song G.,Cai W.,Zhao L.C.
J. Mater. Sci. Technol.    2017, 33 (3): 276-280.  
Abstract   HTML PDF (2219KB)  

The stress induced martensitic phase transformation of spherical ZrCu nanocrystals embedded in an amorphous matrix was studied in this paper. Microstructural observations revealed that the martensitic transformation of the nanocrystal was hindered by the surrounding amorphous coating. The existence of two-step transformation from the austenite phase (B2) to the base structure martensite (B19') and finally to the most stable superstructure martensite (Cm) was also demonstrated. The Cm martensite with (021) type I twinning symmetrically accommodation was surrounded by the B19' martensite with dislocation morphologies.

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Controlled Synthesis of NaV6O15 Nanorods with High Reversible Capacity and Excellent Cycling Stability
Ding Taotao,Xu Juan,Chen Cheng,Luo Zhongwei,Dai Jiangnan,Tian Yu,Chen Changqing
J. Mater. Sci. Technol.    2017, 33 (3): 271-275.  
Abstract   HTML PDF (1327KB)  

In this work, we demonstrate an effective method to improve capacitive performance of NaV6O15 intrinsically by annealing. NaV6O15 nanorods (NRs) prepared by a simple annealing treatment exhibit significantly improved electrochemical performance compared with the untreated NaV6O15 electrode, and yield a high specific capacitance (402.8?F/g at 300?mA/g). Furthermore, the annealing treated nanorods show excellent rate capability and cycling stability (ca. 80% capacitance retention after 1000 cycles at a scan rate of 100?m V/s). Our results have confirmed that the annealing treatment has great influence on the capacitive performance of NaV6O15, which may be attributed to the intrinsic three dimensional (3D) tunneled structures of NaV6O15, and NR morphology. These findings may further broaden the application of NaV6O15-based materials for high performance supercapacitors (SCs), aqueous rechargeable lithium batteries and Li-ion capacitors.

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Magnetic Properties and Coercivity of MnGa Films Deposited on Different Substrates
Feng J.N.,Liu W.,Gong W.J.,Zhao X.G.,Kim D.,Choi C.J.,Zhang Z.D.
J. Mater. Sci. Technol.    2017, 33 (3): 291-294.  
Abstract   HTML PDF (1205KB)  

MnGa films were grown by magnetron sputtering on thermally oxidized Si (Si/SiO2) and glass substrates. Films grown on single-crystal Si (100) substrate with different underlayers were prepared for comparison. It is found that the Si/SiO2 substrate is more suitable for growing high-coercivity MnGa films than the glass substrate, which is the result of the isolated-island-like growth. A coercivity of 9.7?kOe can be achieved for the 10?nm MnGa films grown on Si/SiO2 substrate at substrate temperature TS of 450?°C. Optimized experimental conditions are specified by changing the thickness of the MnGa films and the temperature of the substrates.

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Enhanced Photocatalytic Activity of Bi24O31Br10: Constructing Heterojunction with BiOI
Lou Xi,Shang Jun,Wang Liang,Feng Haifeng,Hao Weichang,Wang Tianmin,Du Yi
J. Mater. Sci. Technol.    2017, 33 (3): 281-284.  
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Bismuth-based compounds have been regarded as an important class of visible-light photocatalysts due to their special electronic structures. In this paper, iodide ions are introduced to modify bismuth-based compound, Bi24O31Br10, forming a Bi24O31Br10/BiOI heterojunction structure. A significant enhancement of photocatalytic activity compared to the parent compounds is observed in de-coloration of rhodamine B (Rh.B) solution. The improved photocatalytic property of Bi24O31Br10/BiOI heterojunction is ascribed to the unique electronic structure consisting of complementary band structures of BiOI and Bi24O31Br10. Iodide ions are regarded as an effective reagent to construct bismuth-based photocatalytic heterojunctions with improved photocatalytic activity.

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Safe growth of graphene from non-flammable gas mixtures via chemical vapor deposition
Feng Ying,J. Trainer Daniel,Peng Hongshang,Liu Ye,Chen Ke
J. Mater. Sci. Technol.    2017, 33 (3): 285-290.  
Abstract   HTML PDF (2136KB)  

Chemical vapor deposition has emerged as the most promising technique for the growth of graphene. However, most reports of this technique use either flammable or explosive gases, which bring safety concerns and extra costs to manage risk factors. In this article, we demonstrate that continuous monolayer graphene can be synthesized via chemical vapor deposition technique on Cu foils using industrially safe gas mixtures. Important factors, including the appropriate ratio of hydrogen flow and carbon precursor, pressure, and growth time are considered to obtain graphene films. Optical measurements and electrical transport measurements indicate graphene films are with comparable quality to other reports. Such continuous large area graphene can be synthesized under non-flammable and non-explosive conditions, which opens a safe and economical method for mass production of graphene. It is thereby beneficial for integration of graphene into semiconductor electronics.

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Electrical and Corrosion Properties of Titanium Aluminum Nitride Thin Films Prepared by Plasma-Enhanced Atomic Layer Deposition
Yun Eun-Young,Lee Woo-Jae,Min Wang Qi,Kwon Se-Hun
J. Mater. Sci. Technol.    2017, 33 (3): 295-299.  
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Titanium-aluminum-nitride (TiAlN) films were grown by plasma-enhanced atomic layer deposition (PEALD) on 316L stainless steel at a deposition temperature of 200?°C. A supercycle, consisting of one AlN and ten TiN subcycles, was used to prepare TiAlN films with a chemical composition of Ti0.25Al0.25N0.50. The addition of AlN to TiN resulted in an increased electrical resistivity of TiAlN films of 2800 µΩ cm, compared with 475 µΩ cm of TiN films, mainly due to the high electrical resistivity of AlN and the amorphous structure of TiAlN. However, potentiostatic polarization measurements showed that amorphous TiAlN films exhibited excellent corrosion resistance with a corrosion current density of 0.12 µA/cm2, about three times higher than that of TiN films, and about 12.5 times higher than that of 316L stainless steel.

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Synthesis of Mesoporous Anatase TiO2 Sphere with High Surface Area and Enhanced Photocatalytic Activity
Lu Tianliang,Wang Youqiang,Wang Yingli,Zhou Lipeng,Yang Xiaomei,Su Yunlai
J. Mater. Sci. Technol.    2017, 33 (3): 300-304.   DOI: 10.1016/j.jmst.2016.03.019.
Abstract   HTML PDF (1513KB)  

Mesoporous anatase TiO2 spheres with high surface area (119?m2?g-1) were successfully synthesized via a facile and green template-free method. The prepared TiO2 was characterized by X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and UV-vis absorbance spectra. It was found that the prepared TiO2 is characterized by pure anatase phase, which shows uniform spheres and has a typical mesostructure with a high specific surface area and a large pore volume. The effects of complexant (acetylacetone) amount, crystallization temperature and calcination temperature were also investigated. Based on the results, a sketch for the preparation of mesoporous TiO2 was proposed. First, complex formed between tetrabutyl titanate and acetylacetone in ethanol. After introduction of aqueous of ammonia sulfate and urea, hydrolysis of tetrabutyl titanate would occur slowly, and sol of TiO2 was formed. Then, crystallization proceeded under hydrothermal conditions. Calcination process favored the formation of bigger TiO2 crystal through combining of the small crystals in TiO2. This led to the formation of bigger mesopores between TiO2 crystals. Photocatalytic activity of the prepared TiO2 was evaluated by decomposition of methyl orange.

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Comparative Study about Degradation of High-purity Magnesium Screw in Intact Femoral Intracondyle and in Fixation of Femoral Intracondylar Fracture
Han Pei,Cheng Pengfei,Zhao Changli,Zhang Shaoxiang,Zhou Runhua,Zhang Xiaonong,Chai Yimin
J. Mater. Sci. Technol.    2017, 33 (3): 305-310.  
Abstract   HTML PDF (1756KB)  

Bone screws encounter complex mechanical environment in fracture fixation of weight-bearing bone. In the present study, high-purity magnesium (HP Mg) screws were applied in fixation of rabbit femoral intracondylar fracture with 3?mm gap. In the control group, HP Mg screws of the same design were implanted at corresponding position of contralateral leg. At 4, 8 and 16 weeks after surgery, retrieved femurs went through micro-computed tomography (micro-CT) scanning and hard tissue processing. Under mechanical stress involved in fracture fixation, bending of screw bolt was observed at the portion exposed to facture gap at 4 weeks. Then local corrosion at the same portion was detected 16 weeks after surgery, which indicated the accumulation effect of mechanical stress on Mg corrosion. HP Mg screws in the fracture group had no significant difference with the control group in screw volume, surface area, surface-to-volume ratio (S/V). And peri-implant bone volume/tissues volume (BV/TV) and bone volume density (BMD) in the fracture group was comparable to that in the control group. Furthermore, histological analysis showed new formed bone tissues in fracture gap and fracture healing 16 weeks after surgery. Under mechanical stress, HP Mg screw suffered bolt bending and local corrosion at the portion exposed to fracture gap. But it had no influence on the integral corrosion behaviors, osseointegration of HP Mg screw and the fracture healing. Therefore, HP Mg screws possessed good potential in fracture fixation of weight-bearing bones.

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In Situ Synthesis of Core-Shell Li4Ti5O12 @Polyaniline Composites with Enhanced Rate Performance for Lithium-ion Battery Anodes
Hui Yani,Cao Liyun,*,Xu Zhanwei,Huang** Jianfeng,Ouyang Haibo,Li Jiayin,Hu Hailing
J. Mater. Sci. Technol.    2017, 33 (3): 231-238.  
Abstract   HTML PDF (1883KB)  

The core-shell Li4Ti5O12 @polyaniline composites (LP) have been synthesized via an in situ synthesis with different mole ratios (25:1, 50:1 and 100:1, aniline:LTO). As an anode material of lithium-ion batteries, the LP-2 electrodes (50:1) exhibit a high initial reversible capacity of 205 mAh g-1 with an initial coulombic efficiency of 97.6% at 0.1 C. Even at a high current density of 10 C, the reversible capacity of the LP-2 electrodes still remains at 102 mAh g-1. Moreover, the LP-2 electrodes retain an impressive high capacity of 161 mAh g-1 after 100 cycles at 1 C, with 0.11% capacity fading per cycle. The promising electrochemical performance may be attributed to the significantly decreasing charge-transfer impedance of the LP composite and reductive polarity difference between the cathode and the electrolyte.

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