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Cu6Sn5 morphology transition and Its Effect on Mechanical Properties of Eutectic Sn-Ag Solder Joints

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Cu6Sn5 Morphology Transition and Its Effect on Mechanical Pr...

POSS-embedded supramolecular hyperbranched polymers constructed from a 1→7 branching monomer with controllable morphology transitions

2016中国高端SMT学术会议

作者： MING YANG MINGYU LI LING WANG YONGGAO FU JONGMYUNG KIM LVQIAN WENG State Key Laboratory of Advanced Welding Production Technology Shenzhen Graduate School Harbin Institute of Technology China National Electric Apparatus Research Institute

The morphologies of CuSn 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 CuSn grains wereobserved 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 CuSn 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 CuSn grains was examined. Significant differences in shear strength were observed for solder joints with different interfacial CuSn 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 CuSn grains.

关键词： Cu6Sn5 morphology transition lead-free solder shear strength

来源： cnki会议评论

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Science China Chemistry 2018年第3期61卷 311-318页

作者： Xing Wang Yanyu Yang Linfeng Fan Fei Yang Decheng Wu Beijing National Laboratory for Molecular Sciences State Key Laboratory of Polymer Physics & Chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100190 China College of Materials Science and Engineering Zhengzhou University Zhengzhou 450052 China University of Chinese Academy of Sciences Beijing 100049 China

The research on the supramolecular hyperbranched polymers(SHPs) that combines the advantages of supramolecular polymer and hyperbranched architecture has attracted considerable interests in many applications. Here we demonstrate a simple approach to prepare POSS-embedded supramolecular hyperbranched polymers(POSS-SHPs) with varied morphology and size by controlling monomer concentration and mixed solvents. The SHPs formations can further transfer into the core-shell structured micelles by addition of competitive guests based on the double supramolecular driving forces.

关键词： POSS-embedded polymer supramolecular hyperbranched polymer host-guest interaction morphology transition

Sphere-to-rod transition of short-chain PEO-b-PDMS-b-PEO in aqueous solution induced by copolymer concentration

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Chinese Chemical Letters 2008年第11期19卷 1363-1366页

作者： Xiao Li Zhan Bi Chen Qing Hua Zhang Ling Min Yi College of Materials Science and Chemical Engineering Zhejiang University Hangzhou 310027 China Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education Zhejiang Sci-Tech University Hangzhou 310018 China

A short-chain triblock copolymer EO9-DMS7-EO9 was synthesized by coupling reaction of allyl-terminated poly（ethylene oxide） and Si-H-terminated poly（dimethylsiloxane）. The structure and purity of synthesized copolymer was carefully characterized. Self-assembly behavior of EO9-DMST-EO9 triblock copolymer in water was investigated. And it was found that along with the increase of copolymer concentration, morphology of self-assembled aggregates transits from sphere to rod. A plausible understanding of the morphology transition for the investigated triblock copolymer was proposed.

关键词： Block copolymer Self-assembly Polysiloxane morphology transition

One-step laser induced conversion of a gelatin-coated polyimide film into graphene:Tunable morphology,surface wettability and microsupercapacitor applications

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Science China(Technological Sciences) 2021年第5期64卷 1030-1040页

作者： WANG WenTao LU LongSheng XIE YingXi LI ZeHong WU WeiBin LIANG RongXuan TANG Yong School of Mechanical&Automotive Engineering South China University of TechnologyGuangzhou 510641China College of Engineering South China Agricultural UniversityGuangzhou 510642China

Latest advances have witnessed the laser induction process on polyimide(PI)films for the formation of porous ***,a fully converted graphene film was prepared by Nd:YAG laser scribing a gelatin coated PI *** was found that the gelatin played the role of"shield"well in absorbing intense laser impact and benefit for the surface morphology *** treatment lower than a critical fluence point of~4.00 J mm^(-2) contributed to a crater-like surface morphology due to the dispersed nature of Nd:YAG laser *** tuning laser fluence above the threshold,carbonized surface turned into continuous morphology.A fluid dynamics process accompanied by outgassing occurred during the carbonization,and the surface morphology gradually varied from stretched droplets to porous strips and finally to amorphous porous *** morphology evolution in combination with surface chemistry is responsible for the significant wettability transition from superhydrophobic to superhydrophilic,and a Janus superhydrophobic/superhydrophilic surface wettability was achieved under a laser fluence of~8.00 J mm^(-2).Eventually,microsupercapacitors(MSCs)were fabricated to show the great potential of our prepared graphene in flexible electronics.

关键词： laser-induced graphene gelatin morphology transition microsupercapacitor flexible electronics

Energy stored in nanoscale water capillary bridges formed between chemically heterogeneous surfaces with circular patches

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Chinese Physics B 2020年第11期29卷 44-51页

作者： Bin-Ze Tang Xue-Jia Yu Sergey V.Buldyrev Nicolas Giovambattista Li-Mei Xu International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China Department of Physics Yeshiva University500 West 185th StreetNew YorkNY 10033United States Department of Physics Brooklyn College of the City University of New YorkBrooklynNew York 11210United States Ph.D.Programs in Chemistry and Physics The Graduate Center of the City University of New YorkNew YorkNY 10016United States Collaborative Innovation Center of Quantum Matter Beijing 100871China

The formation of nanoscale water capillary bridges(WCBs) between chemically heterogeneous(patchy) surfaces plays an important role in different scientific and engineering applications, including nanolithography, colloidal aggregation, and bioinspired adhesion. However, the properties of WCB of nanoscale dimensions remain unclear. Using molecular dynamics simulations, we investigate the geometrical and thermodynamic properties of WCB confined between chemically heterogeneous surfaces composed of circular hydrophilic patches on a hydrophobic background. We find that macroscopic capillary theory provides a good description of the WCB geometry and forces induced by the WCB on the confining surfaces even in the case of surface patches with diameters of only 4 nm. Upon stretching, the WCB contact angle changes from hydrophobic-like values(θ > 90°) to hydrophilic-like values(θ < 90°) until it finally breaks down into two droplets at wall separations of ~9–10 nm. We also show that the studied nanoscale WCB can be used to store relevant amounts of energy EPand explore how the walls patch geometry can be improved in order to maximize EP. Our findings show that nanoscale WCB can, in principle, be exploited for the design of clean energy storage devices as well as actuators that respond to changes in relative humidity. The present results can also be of crucial importance for the understanding of water transport in nanoporous media and nanoscale engineering systems.

关键词： water capillary bridge energy density morphology transition hydrophilicity