Abstract No.:
5374

 Scheduled at:
Wednesday, June 07, 2017, Hall 27 2:20 PM
Suspension Spraying I


 Title:
Formation of cauliflower-like features and columnar microstructure in suspension plasma sprayed titanium dioxide (TiO2) coatings

 Authors:
Navid Sharifi / Concordia University, Canada
Martin Pugh / Concordia University, Canada
Ali Dolatabadi*/ Concordia University, Canada
Christian Moreau/ Concordia University, Quebec

 Abstract:
Presence of cauliflower-like columnar microstructural features in suspension plasma sprayed coatings is interesting for a variety of applications including thermal barrier coatings, superhydrophobic coatings and electrochemically active electrode materials. In order to obtain desired, reproducible and controllable microstructures in suspension plasma spraying, it is vital to have a deep understanding of the formation mechanism of such features as well as the effect of various process parameters on morphological characteristics of these coatings.
In this work, the formation of the cauliflower-like columnar features in SPS TiO2 coatings has been studied by looking at the splats that collectively generate layers of the coatings. The size distribution, spreading diameter, shape, angle of impact of the splats and presence of partially molten or unmolten particles were investigated using scanning electron microscopy (SEM). Furthermore, by collecting data from splats that resulted from particles travelling in different trajectories through the plasma plume, the effect of particles on the periphery of the bead is studied. Additionally, the effect of overlapping splats from consecutive torch passes on the formation of the microstructure is investigated. Moreover, the effect of process parameters such as suspension solid content, solvent type, substrate roughness, torch power, spray distance and plasma gas velocity on the characteristics of the splats is studied.


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