Shenzhen Key Laboratory of Advanced Materials

Shenzhen, China

Shenzhen Key Laboratory of Advanced Materials

Shenzhen, China
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Sun R.,Harbin Institute of Technology | Sun R.,Shenzhen Key Laboratory of Advanced Materials | Wanga G.-G.,Harbin Institute of Technology | Wanga G.-G.,Shenzhen Key Laboratory of Advanced Materials | And 13 more authors.
Journal of Alloys and Compounds | Year: 2013

N-incorporated Ga2O3 films were successfully prepared on sapphire substrates in Ar-N2 gas mixtures by radio frequency magnetron sputtering. The influence of N2 gas flux on microstructure, surface morphology and optical properties of N-incorporated Ga2O3 films was analyzed in detail. The films have better crystalline quality after nitrogen incorporating properly, while keeping their original b-Ga2O 3 crystalline structure. The surface morphology of the N-incorporated Ga2O3 films was investigated by atomic force microscopy (AFM). The photoluminescence spectra consisted of ultraviolet emission peak and green emission band were also observed and discussed. The optical transmittance of the as-deposited N-incorporated Ga2O3 films exceeds 80% in the visible range. The optical band gap decreases with increasing the N2 gas flux, resulting from the formation of Ga-N bonds. © 2013 Elsevier B.V. All rights reserved.


Wang S.,Shenzhen Key Laboratory of Advanced Materials | Ji H.,Shenzhen Key Laboratory of Advanced Materials | Li M.,Shenzhen Key Laboratory of Advanced Materials | Li M.,Harbin Institute of Technology | Wang C.,Harbin Institute of Technology
Materials Letters | Year: 2012

We report a Cu-to-Cu interconnects fabrication process based on the pressureless low temperature sintering of Ag nanoparticles for electronic packaging. The organic shells of citrates covering the nanoparticles stabilize the Ag nanoparticles. It is not necessary for organic shells to be completely decomposed for sintering to take place. Instead, it is sufficient that the chemical bonds that connect the organic shells with Ag nanoparticles are broken. This new point of view leads to a way to lower bonding temperature. A novel pinecone-like recrystallization morphology of sintered Ag nanoparticles is obtained, which results from the residuals of organic shells by the sintering process. The effect of recrystallization morphology on the thermal conductivity of sintered Ag nanoparticles is discussed. The shear strength of joints reaches 17-25 MPa at temperatures ranging from 423 K to 473 K. © 2012 Elsevier B.V. All rights reserved.


Zeng Y.,Harbin Institute of Technology | Zeng Y.,Shenzhen Key Laboratory of Advanced Materials | Wu J.,Harbin Institute of Technology | Wu J.,Shenzhen Key Laboratory of Advanced Materials | And 3 more authors.
International Journal of Hydrogen Energy | Year: 2014

With recent progress in lowering the operating temperature, chromia-forming ferritic stainless steels are considered as promising interconnect materials for solid oxide fuel cells (SOFCs). To block the chromium evaporation and chromium poisoning, coatings with Mn/Co (40:60) was tested as the optimized recipe to maintain Mn1.5Co1.5O4 composition after long term operation due to Mn diffusion from substrate. In order to study the coating thickness effect, Mn/Co (40:60) coatings were fabricated in thickness of approximately 800 nm, 1500 nm, 3000 nm on ferritic stainless steels SUS430 using magnetron sputtering. Oxidation behavior of sputtered samples was investigated after oxidized at 800 °C in air for 2 h, 250 h, 500 h, 1000 h, respectively. SEM, EDS, XRD and FIB are used to analyze the surface morphology, chemical composition and structures of the coatings. Area specific resistance measurement indicated the sputtered samples in thickness of 800 nm, 1500 nm, 3000 nm at 800 °C for various hours in air are in range of 15-36 mΩ cm2, 12-25 mΩ cm2, 10-23 mΩ cm2 respectively. Eventually the optimized thickness of Mn/Co (40:60) coatings was suggested. © 2013 Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Li Z.,Tianjin University | Cui Y.,Harbin Institute of Technology | Cui Y.,Shenzhen Key Laboratory of Advanced Materials | Wu J.,Harbin Institute of Technology | And 4 more authors.
RSC Advances | Year: 2016

Lithium zinc titanate (Li2ZnTi3O8) anode material has been synthesized via a microwave method for the first time. The physical and electrochemical performances of the as-prepared sample are characterized by X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic charge-discharge tests, cyclic voltammetry (CV) tests, and electrochemical impedance spectroscopy (EIS). It is found that the pristine Li2ZnTi3O8 obtained via the microwave method at 780 W for 10 min exhibits a typical cubic spinel structure with P4332 space group. The electrochemical measurements indicate that the Li2ZnTi3O8 anode material displayed a highly reversible capacity and excellent cycling stability. The initial charge capacities of Li2ZnTi3O8 nanoparticles were 216.8 mA h g-1, 197.4 mA h g-1, 192.6 mA h g-1, 174.5 mA h g-1 at 50 mA g-1, 100 mA g-1, 300 mA g-1 and 500 mA g-1, respectively. After 50 cycles, charge capacities of 263.5 mA h g-1, 234.8 mA h g-1, 223.2 mA h g-1 and 208.4 mA h g-1 can be retained, with no significant capacity fading. This indicates that the microwave method has a great potential application in synthesizing Li2ZnTi3O8 anode materials for lithium ion batteries. © The Royal Society of Chemistry 2016.


Sun R.,Harbin Institute of Technology | Sun R.,Shenzhen Key Laboratory of Advanced Materials | Zhang H.-Y.,Harbin Institute of Technology | Zhang H.-Y.,Shenzhen Key Laboratory of Advanced Materials | And 10 more authors.
Ceramics International | Year: 2014

GaN nanowires were synthesized on sapphire substrates by chemical vapor deposition. The selective growth of GaN nanowires was obtained through an N-Ga2O3 layer prepared by radio frequency magnetron sputtering. The X-ray diffraction (XRD) and Raman measurements indicated the GaN nanowires to be all indexed to the hexagonal wurtzite structure. The photoluminescence (PL) spectra were composed of a strong UV emission peak (365 nm) and a weak yellow luminescence (YL) band (∼600 nm). The selective growth mechanism of GaN nanowires was briefly discussed. © 2014 Elsevier Ltd and Techna Group S.r.l.


Zhang H.,Harbin Institute of Technology | Zhang H.,Shenzhen Key Laboratory of Advanced Materials | Wu J.,Harbin Institute of Technology | Wu J.,Shenzhen Key Laboratory of Advanced Materials | And 3 more authors.
International Journal of Hydrogen Energy | Year: 2013

The spinel structure of manganese cobalt oxide (Mn,Co)3O 4 is one of the most promising coatings for solid oxide fuel cell (SOFC) stainless steel interconnects. The stoichiometric Mn1.5Co 1.5O4 composition has properties that are preferable to other Mn/Co ratios, for example a higher conductivity and a thermal expansion coefficient that matches the typical steel substrate. However, previous work showed the Mn/Co ratio changes during operation due to the diffusion of Mn from the substrate. The results presented here are on three coatings with different compositions (namely; pure Co, Mn20Co80, and Mn 40Co60) with each coating composition deposited to a thickness of 800 nm, 1500 nm, and 3000 nm. The coatings were applied by DC magnetron sputtering and then machine cut into coupons for isothermal annealing at 800 °C in air using a batch-type furnace for 2, 10, 50, 250, and 1000 h. The morphology, chemical composition (including surface and cross sections of the layers) and structures of the oxides formed were analyzed by SEM, EDS and XRD. Analysis of the element diffusion (Mn, Co, Cr, Fe) shown here points to an optimized coating recipe of Mn40Co60. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Zheng L.,Shenzhen Key Laboratory of Advanced Materials | Song S.-H.,Shenzhen Key Laboratory of Advanced Materials
Philosophical Magazine Letters | Year: 2013

Heat-affected zones (HAZs) were simulated with a peak temperature of 1320 °C at different welding heat inputs for a Cr-Mo low-alloy steel. The ductile-to-brittle transition temperature (DBTT) of the HAZs increased with increasing heat input. When 0.05 wt.% Sb was added to the steel, the DBTTs of the HAZs became 1 and 10°C higher than those for the undoped steel at heat inputs of 36 and 60 kJ/cm, respectively. Sb segregation to austenite grain boundaries during thermal cycling was found to be mainly responsible for the DBTT increase. © 2013 Taylor and Francis Group, LLC.


Song S.-H.,Shenzhen Key Laboratory of Advanced Materials | Zheng L.,Shenzhen Key Laboratory of Advanced Materials
Materials Science and Technology (United Kingdom) | Year: 2014

Phosphorus induced embrittlement of welding heat affected zones (HAZs) in a 2.25Cr-1Mo steel was examined by measuring the ductile to brittle transition temperature (DBTT) of the HAZs simulated with a peak temperature of 1320°C at different welding heat inputs. At the same heat input, the DBTTs of the HAZs in the P doped samples were apparently higher than those in the undoped samples and phosphorus grain boundary segregation was mainly responsible for the DBTT increase. A critical welding heat input was found to be between 36 and 100 kJ cm-1, being close to 60 kJ cm-1, at which the maximum segregation of phosphorus could be produced during the corresponding thermal cycling, leading to the maximum DBTT difference between the P doped and undoped samples. © 2014 Institute of Materials, Minerals and Mining.


Ravi M.,Shenzhen Key Laboratory of Advanced Materials | Song S.,Shenzhen Key Laboratory of Advanced Materials | Gu K.,Shenzhen University | Tang J.,Shenzhen University | Zhang Z.,University of Portsmouth
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2015

Lithium ion conducting polymer electrolyte films based on biodegradable poly(∈-caprolactone) (PCL) complexed with lithium thiocyanate (LiSCN) salt were prepared by solution cast technique. Thermal and electrical properties of the polymer electrolyte films were studied using differential scanning calorimetry (DSC) and ac impedance spectroscopy. In order to investigate the ion conduction mechanism and relaxation behavior of complex polymer electrolyte films, the conductivity, dielectric constant, loss tangent and electric modulus were analyzed as a function of frequency and temperature. The variation of conductivity with frequency obeyed the Johnscher's power law. The dielectric constant exhibited a higher value at a lower frequency and increased with rising temperature due to the polar nature of host polymer. The activation energies for both dc conductivity and relaxation had the same value (∼0.87 eV), implying that the charge carriers responsible for both conduction and relaxation were the same. © 2015 Elsevier B.V. All rights reserved.

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