Search results for: Wang Chunqing
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Add CeO2 in medium phosphorus content Ni-P composite coating has been attracted attention in recent years. So, we add different amounts and different size of CeO2 in the nickel plating solution, then the morphology and crystal structure of the coating are characterize by scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) respectively. As a result, the content of CeO2 in the coating...
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In this paper, the influence of nano-CeO2 and micro-CeO2 with different amounts were discussed after they were added into low phosphorus content Ni-P composite coating. The microstructure and crystal structure of the coating were observed by scanning electron microscope (SEM) and X-ray diffraction analysis (XRD) respectively. The results showed that whether nano-CeO2 or micro-CeO2, both refined the...
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Electroless Ni (EN) technology is widely used in electronic package field and the high phosphorus composite EN technology was studied. In this paper, we discussed the influence of nano-CeO2 and micro-CeO2 particles with different amounts when they were added in high phosphorus content Ni-P composite coating. The microstructure and crystal structure of the coating were observed by scanning electron...
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With the integrated circuit and semiconductor industry develop rapidly, the traditional flat package can't meet the demands for higher performance and lower cost requirements for handheld and portable electronic devices any more in the semiconductor industry. The 3D stacked package technology is a developing method to fit the integrated circuit advanced high-density packaging, which can easily meet...
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Rare Metal Materials and Engineering > 2015 > 44 > 7 > 1617-1622
Mg92Zn4Y4 and Mg92Zn4Y3Gd1 alloys with long period stacking ordered (LPSO) structure phases were prepared by conventional solidification process. By OM, SEM, EDS, XRD and TEM analysis the phases and 14H-LPSO structures of the two alloys were characterized. The results show that as-cast Mg-alloy with the atomic ratio of Zn/RE = 1 will lead to LPSO phase; adding of Gd element to Mg92Zn4Y4 alloy can...
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In view of the problems that the enterprise equipment's updated and diagnosis works difficult to be quantified, a new equipment renewal method is proposed based on the analytic hierarchy process (AHP) and variation coefficient method. The indexes weight is determined by a combination weighting way; furthermore, the fuzzy comprehensive evaluation method is introduced to analyze and calculate the portfolio...
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Sn-3.5Ag nanosolder in tiny sizes can provide a practical way to solve the high soldering temperature problem of lead-free solder alloy in fine pitch interconnectivity owing to the unique nanosize effect and meantime stand a higher working temperature just as the bulk material after welding. In this paper, a simple approach to synthesis Sn-3.5Ag nanoparticles by chemical reduction at room temperature...
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Sn-3.5Ag nanosolder in tiny sizes can provide a practical way to solve the high soldering temperature problem of lead-free solder alloy in fine pitch interconnectivity owing to the unique nanosize effect and meantime stand a higher working temperature just as the bulk material after welding. In this paper, a simple approach to synthesis Sn-3.5Ag nanoparticles by chemical reduction at room temperature...
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In this paper, a LED multi-chip module with a heat pipe was designed for automotive headlights, which took advantages of the relative air flow during vehicle travelling for forced convection to keep the junction temperature of LED chips below 60?. The Structure is compact enough to be suitable for placement in a small space for automotive lighting. The influence of paraments on the junction temperature...
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With the method of copper-coating 100µm Diamonds was added into Sn3.0Ag0.5Cu(SAC305) solder to acquire Diamond/SAC305 composite solder bumps on Cu pad, which is considered to be a potential material to improve the thermal management of HB-LEDs, on account of the favorable conducting property of diamonds. Not only was a relatively high (7 wt. %) and controllable addition amount of diamonds achieved,...
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In this paper, the hot cutting surface and edge formed at green state are characterized and researched. Surface morphology of the hot-cutting green state and co-fired state is observed by optical microscope and SEM, and compared with that of the natural surface that formed in tape casting. The Weibull statistical strength test is introduced to evaluate the influence to the quality and reliability...
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This article adopts the Primary Energy Ratio (PER) to evaluate the performances of air conditioning heat and cold sources (refrigerator/ electric heat pump, LiBr absorption unit, gas air conditioning unit and boiler) and compares different Heat and Cold Sources in building Air Conditioning. The result shows that air conditioning unit driven by electrical power is most suitable for the places with...
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Normally, The air-source heat pump (ASHP) can not work well in the serious cold regions of china in winter. In order to study this issue, the experiment system of Air-source Heat Pump using exhaust of building as Heating Source was developed, the system used the surplus energy of exhaust fully, raised the air temperature of ASHP, recovered the energy of exhaust by direct exchange, and heated fresh...
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Design of Engineering-to-Order (ETO) product is a process describing various constraints with manifold knowledge to meet customer need in mass customization (MC). With the increase of parts' number and design complexity of ETO product, configuration knowledge including those supporting variant design became more and more. Consequently, reasoning and sharing of knowledge became worse and worse and...
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Shear behavior of Sn-3.0Ag-0.5Cu solder joints on ball grid array substrates was investigated with different solder volumes and shear speeds to study the solder volume effect on shear properties. Both solder volume and shear speed were found to have strong effect on the shear strength. The shear force decreases obviously with the decrease of the solder volume due to the significant decrease of loaded...
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Au surface finish is common used as a protection layer on pads. In the traditional reflow process, Au will be dissolved into solder and form AuSn4 IMCs (intermetallic components). However, as for the solder joints fabricated by laser soldering, the morphology and distribution of the AuSnx IMCs are quite different from that in solder joints fabricated by traditional reflow methods. The formation, distribution...
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In this work, two eutectic solders: 80Au20Sn and 52In48Sn were chosen for fiber bonding through laser soldering, and scanning electronic microscope (SEM) equipped with energy dispersive x-ray detector (EDX) was used to investigate the microstructures of at four interfaces between two solders and two metallizations: Au-Sn/(Au/Ti), Au-Sn/( Au/Ni), In-Sn/ (Au/Ti), In-Sn/(Au/Ni). Results show that as...
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Fiber attachment soldering is low cost and high-precision technology in direct-coupling optoelectronic packaging. The three-dimensional shape of solder joint in fiber attachment soldering was predicted by using the public domain software called Surface Evolver. The influences of material and manufacturing parameters on solder joint geometry and the stand-off height were investigated. The results can...
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The bonding procedure of copper wire ball bonding on an aluminum-metallized silicon substrate was investigated in this paper. The four crucial parameters: ultrasonic power, impact force, frequency duration and bonding temperature were optimized. It was found that the process window was quite narrow, thus the bonding process was less stable. In conjunction with the results of the process optimization,...
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Journal of Materials Science > 2005 > 40 > 8 > 1993-2001
The effects of displacement rate on fracture behaviors of 100Sn solder and 63Sn37Pb solder alloys have been investigated by SEM in-situ testing. It was found that for the 100Sn solder, grain boundary sliding was the dominant deformation mechanism at lower tensile rate regime, while a large area of slip lines crossing grains were detected at the surface of specimens at higher tensile rate regime. For...
