Abstract No.:
2659

 Title:
Effect of accelerating gas flow on pore structure and ion diffusion property of vacuum cold sprayed TiO2 coatings using strengthened nanostructured powder

 Authors:
Guan-Jun Yang* / School of Materials Science and Engineering, Xi'an Jiaotong University, China
Kai-Xing Liao/ 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
Cheng-Xin Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
Shan Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China

 Abstract:
The pore structure in nano-porous TiO2 coatings influences the ion diffusion property and photovoltaic performance of dye-sensitized solar cell. In this paper, TiO2 coatings were deposited through vacuum cold spray at different accelerating gas flow rates using a strengthened nanostructured powder as feedstock. The pore structure and ion diffusion property were characterized to clarify the coating formation mechanism. Results show that the coating porosity slightly decreased with increasing particle velocity and gas flow rate. It is interestingly found that the pores presented a bimodal size distribution, i.e. ~15 nm and ~50 nm. Compared with the conventional unimodal-sized nano-porous coating, the TiO2 coatings with a bimodal size distribution exhibited much higher ion diffusion coefficient. Based on the impact behavior of the spray powder, a coating deposition model was proposed to explain the deposition mechanism of the strengthened nanostructured powder during vacuum cold spray.

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