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| Abstract No.: |
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Scheduled at:
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Friday, May 23, 2014, Hall H2 3:00 PM
Cold Gas Spraying 4
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| Title: |
Inter-nanoparticle connection in vacuum cold sprayed nano-TiO2 coating characterized by HRTEM and molecular dynamics simulation
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| Authors: |
Guan-Jun Yang / School of Materials Science and Engineering, Xi'an Jiaotong University, China
Hai-Long Yao* / State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
Cheng-Xin Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
Chang-Jiu Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
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| Abstract: |
Inter-particle connection plays an important role in determining coating properties. For example, the effective inter-nanoparticle connection in photoanode could contribute to a high photo-to-electric energy conversion efficiency for dye-sensitized solar cells. Up to now, the particle connection was indirectly investigated in most studies by electron transport property using electrochemical methods. In this study, to aim at understanding the nano-particle connecting behavior during vacuum cold spraying, the particle connection in the vacuum cold-sprayed coating was characterized by high resolution transmission electron microscopy (HRTEM). Two coatings deposited at two different deposition conditions, i.e. room temperature spraying and in situ particle-heating spraying, were examined. For comparison, particle connection in the screen-printed TiO2 coating with high temperature sintering was also examined. Results show that the effective particle connection was formed in the coating sprayed with in-situ particle-heating and screen-printed coating sintered at high temperature, while weak bonding was observed for the screen-printed coatings without sintering. To aim at understanding the formation mechanism of the particle connection, the molecular dynamics simulation is employed to examine the particle connecting behavior at different deposition conditions. It was found that the effective particle connection is attributed to the rough surface morphology of the nano-particles and the high impact pressure resulting from a high particle velocity. Furthermore, the high temperature and impact compaction present a synergistic effect on the particle connection formation in nano-TiO2 coating during vacuum cold spraying.
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