China National Electrical Apparatus Research Institute

Guangzhou, China

China National Electrical Apparatus Research Institute

Guangzhou, China
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Wang M.,CAS Shenyang Institute of Metal Research | Wang J.,CAS Shenyang Institute of Metal Research | Feng H.,China National Electrical Apparatus Research Institute | Ke W.,CAS Shenyang Institute of Metal Research
Corrosion Science | Year: 2012

The aim of this study is to evaluate the effects of Ag 3Sn intermetallic compounds (IMCs) on corrosion of Sn-3.0Ag-0.5Cu (SAC305) solder alloy under high-temperature and high-humidity condition. The Ag 3Sn IMCs of SAC305 with various size and morphology were obtained by changing cooling rate. Commercial SAC305 solder with smallest Ag 3Sn IMCs exhibits better corrosion resistance than air-cooled and furnace-cooled SAC305 solders because microgalvanic corrosion between large cathodic Ag 3Sn IMCs plates and anodic Sn matrix decreased the corrosion resistance of air-cooled and furnace-cooled SAC305 solders. © 2012 Elsevier Ltd.


Wang M.,CAS Shenyang Institute of Metal Research | Wang J.,CAS Shenyang Institute of Metal Research | Feng H.,China National Electrical Apparatus Research Institute | Ke W.,CAS Shenyang Institute of Metal Research
Journal of Materials Science: Materials in Electronics | Year: 2012

The heterogeneous microstructure of solder could be obtained when cooling rate of the solder joint was not even, which would affect the corrosion behavior of solder during service. The ambient temperature would also affect the corrosion behavior of solder joint. In this paper, the effects of microstructure and temperature on the corrosion behavior of Sn-3.0Ag-0.5Cu (SAC305) lead-free solder were investigated. The various microstructures of SAC305 lead-free solder were obtained by cooling specimens in air and furnace. Compared to the fine-fibrous Ag 3Sn phase inside the commercial SAC305 solder, platelet-like Ag 3Sn formed as cooling speed decreasing. The polarization behavior of SAC305 solders in 3.5 wt.% NaCl solution was not significantly affected by various microstructures, but sensitive to temperature. © 2011 Springer Science+Business Media, LLC.


Wang M.,CAS Shenyang Institute of Metal Research | Wang J.,CAS Shenyang Institute of Metal Research | Feng H.,China National Electrical Apparatus Research Institute | Ke W.,CAS Shenyang Institute of Metal Research
Materials Science and Engineering A | Year: 2012

The effect of microstructure and corrosion on fracture behavior of Sn-3.0Ag-0.5Cu (SAC305) solder alloy was in-situ studied at three-point bending test using environmental scanning electron microscopy (ESEM). The results showed that the microcracks initiated at the Sn boundaries in the Β-Sn region for commercial SAC305 solder. For furnace-cooled SAC305 solder, cracks preferred to initiating and propagating along Sn boundaries and Sn/Ag 3Sn interface. Ag 3Sn plates were easily broken during the bending test. The fracture behavior was significantly affected by corrosion. The most vulnerable area to fracture is the corroded region of the specimen. © 2012 Elsevier B.V.


Wang X.,Anhui University of Science and Technology | Hu Y.,Anhui University of Science and Technology | Hu Y.,Suzhou University of Science and Technology | Song L.,Anhui University of Science and Technology | And 4 more authors.
Polymer | Year: 2010

A series of flame-retardant epoxy resins (EP) with different content of poly(DOPO substituted dihydroxyl phenyl pentaerythritol diphosphonate) (PFR) were prepared. The PFR was synthesized via the polycondensation between 10-(2,5-dihydroxyl phenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-BQ) and pentaerythritol diphosphonate dichloride (SPDPC). The structure of PFR was confirmed by Fourier transform infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). The flame retardancy and the thermal stability of the EP/PFR hybrids were investigated by limiting oxygen index (LOI) test and thermogravimetric analysis (TGA) in air. The results showed that the incorporation of PFR into EP can improve the thermal stability dramatically. The mechanical results demonstrated that PFR enhanced failure strain slightly accompanied by a decrease in tensile strength. The thermal oxidative degradation mechanisms of the EP/PFR hybrids were investigated by real time Fourier transform infrared spectra (RTFTIR) and direct pyrolysis/mass (DP-MS) analysis. X-ray photoelectron spectroscopy (XPS) was used to explore chemical components of the residual char of EP and EP/PFR hybrid. DP-MS analysis showed that the degradation process of EP/PFR hybrid was divided into two characteristic temperature regions, attributed to the decomposition of phosphate and aromatic structure. © 2010.


Yang M.,Harbin Institute of Technology | Li M.,Harbin Institute of Technology | Wang L.,China National Electrical Apparatus Research Institute | Fu Y.,China National Electrical Apparatus Research Institute | And 2 more authors.
Journal of Electronic Materials | Year: 2011

The morphologies of Cu 6Sn 5 grains formed at the interface between Sn-3.5Ag (wt.% unless otherwise specified) and Cu substrates were studied in this work. Reflow experiments were performed for 60 s at peak temperatures of 513 K, 533 K, 543 K, and 553 K. Two morphologies of interfacial Cu 6Sn 5 grains were observed in wetting reactions: prism type, above 543 K, and scallop type, below 533 K. During aging, the two morphologies gradually transitioned to layer type. These three morphologies could be transformed into each other as long as the corresponding condition changed. The morphology transition of Cu 6Sn 5 in the wetting reaction was explained by the change in Jackson's parameter with temperature. In addition, the effect of the Cu content in molten solder on interfacial Cu 6Sn 5 grains was examined. Significant differences in shear strength were observed for solder joints with different interfacial Cu 6Sn 5 morphologies in the case of a lower shear height. Joint strength is discussed in terms of the microstructure of the solder matrix and the morphology of interfacial Cu 6Sn 5 grains. © 2010 TMS.


Yang M.,Harbin Institute of Technology | Li M.,Harbin Institute of Technology | Wang L.,China National Electrical Apparatus Research Institute | Fu Y.,China National Electrical Apparatus Research Institute | And 2 more authors.
Materials Letters | Year: 2011

The growth behavior of Cu6Sn5 grains formed at an Sn3.5Ag/Cu interface was investigated. During soldering, Cu6Sn 5 grains formed at the interface, showing a flattened ovoid shape. During solidification, Cu precipitated from molten solder in the form of Cu 6Sn5, forming faceted surfaces on existing interfacial grains. The interfacial Cu6Sn5 morphology was unrelated to its crystal orientation, which was primarily dependent on reaction temperature. A reaction temperature of 240 °C led to an increase in (002) growth and a decrease in (101) growth with time. However, the (002) plane peak was not detected in the interfacial grains formed at a higher reaction temperature (280 °C). © 2011 Elsevier B.V. All rights reserved.


Chen H.T.,Harbin Institute of Technology | Wang L.,China National Electrical Apparatus Research Institute | Han J.,Harbin Institute of Technology | Li M.Y.,Harbin Institute of Technology | And 2 more authors.
Journal of Electronic Materials | Year: 2011

In this study, the effect of mechanical stresses on the recrystallization behavior of Sn-3.0Ag-0.5Cu Pb-free solder interconnects was studied by four-point cyclic bending, shear tests, and tensile tests. Scanning electronic microscopy with electron backscattered diffraction was used to characterize the microstructure and crystallographic orientation of the solder interconnects. The results show that recrystallization occurs under the different mechanical stresses in these tests at room temperature, and that recrystallized grains evolve from subgrains by rotation. Microhardness measurements after shear tests show that the hardness of the recrystallized microstructure was decreased by 15% and 41%, respectively, compared with that of the nonrecrystallized and as-solidified microstructures. Furthermore, the fine-grained microstructure produced after recrystallization facilitated grain boundary sliding. Therefore, the deformation and cracking behaviors were localized in the degraded recrystallized microstructures once recrystallization occurred, accelerating failure of the solder interconnects. © 2011 TMS.


Tan R.,South China University of Technology | Yang P.,Guangdong Key Laboratory of Clean Energy Technology | He P.,South China University of Technology | Wang J.,China National Electrical Apparatus Research Institute
Dianwang Jishu/Power System Technology | Year: 2013

To analyze factors influencing reliability indices of collection system of offshore wind farms, the failures of all cables, switchgears and wind turbines that possibly occur are taken into account in the established reliability model, and a reliability evaluation algorithm of collection system under traditional switchgear configuration scheme and complete switchgear configuration scheme is proposed. Through actual calculation example, the reliability indices under the two switchgear configuration schemes are contrasted, the sensitivity analysis on the annual fault times and the time for fault maintenance of cables, switchgears and wind power generation units, which affect the reliability of the topology, are emphatically contrasted. Comparison results show that the incidences of failure rate of different equipments on the reliability of the topology are not the same, the impact of failure rate of cables on reliability of the topology is the greatest, and the failure rates of switchgears and wind turbines are in the second place. The sensitivity of equipments is also affected by switchgear configuration scheme. Inside the variation range of reliability parameters of equipments in offshore wind farms, the outage rate under complete switchgear configuration scheme is obviously lower than that under traditional switchgear configuration scheme.


Zhao K.,Anhui University of Science and Technology | Xu W.,Anhui University of Science and Technology | Xu W.,Anhui University of Architecture | Song L.,Anhui University of Science and Technology | And 3 more authors.
Polymers for Advanced Technologies | Year: 2012

Microencapsulated ammonium polyphosphate (MAPP) with polyurethane resin has been prepared by in situ polymerization. The combination of MAPP and boron phosphate (BP) on the flammability properties of thermoplastic polyurethane (TPU) was studied by vertical burning (UL-94) tests, limiting oxygen index tests, cone calorimetry (CONE), and microscale combustion calorimeter (MCC) whereas thermal stability was investigated by thermogravimetric analysis and real-time Fourier transform infrared. Results showed that a suitable substitution of MAPP by BP could improve flame retardancy of the TPU/MAPP composites and TPU composites with MAPP/BP (15.5/2wt%) achieving UL-94 V-0 rating. The CONE and MCC data showed synergistic effects between BP and MAPP in the composites. © 2011 John Wiley & Sons, Ltd.


Zhang X.,South China University of Technology | Zhang X.,University of British Columbia | Zhao X.,China National Electrical Apparatus Research Institute | Hu J.,China National Electrical Apparatus Research Institute | And 2 more authors.
Journal of Hazardous Materials | Year: 2011

Adsorption on carbon fixed-beds is considered as an inexpensive and highly effective way for controlling chlorofluorocarbons (CFCs) emissions. In the present work, a dynamic model under constant-pattern wave conditions has been developed to predict the breakthrough behavior of trichlorofluoromethane (CFC-11) adsorption in a fixed bed packed with activated carbon fibers (ACFs). The adsorption of CFC-11 vapor onto viscose-based ACFs was performed in a fixed bed at different test conditions. The results showed that, in a deep bed (>120. mm), the analytical model based on the external mass transfer with the Langmuir isotherm could describe the adsorption dynamics well. The model parameters, the characteristic breakthrough time and the film mass-transfer coefficients are related to such operating parameters as the superficial gas velocity, feed concentration and bed height. It was found from the breakthrough dynamics that the mass transfer from the fluid phase to the fiber surface dominated the CFC-11 adsorption onto ACFs in fixed beds. © 2010 Elsevier B.V.

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