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Thursday, May 18, 2006 - 11:20 AM
EAP7.3

Impact of Partially Molten Plasma-Sprayed Zirconia Particles on Glass Surfaces

C. Moreau, National Research Council Canada (CNRC-NRC), Boucherville,, QC, Canada; A. McDonald, University of Toronto, Toronto, ON, Canada; S. Chandra, Centre for Advanced Coating Technology, University of Toronto, Toronto, ON, Canada

Plasma-sprayed yttria-stabilized zirconia particles (~40 µm diameter) were photographed during impact (velocity ~200 m/s) on a glass surface that was maintained at either room temperature or 400°C. A droplet that approached the surface was sensed using a photodetector and after a known delay, a light source was triggered to illuminate the particle in order to photograph it with a CCD camera. A rapid two-color pyrometer was used to collect the thermal radiation from the particles to follow the evolution of their temperatures and size, in-flight and after impact. The fully molten particles spread into a thin film liquid splat after impacting the surfaces. The partially molten particles disintegrated into small satellite fragments immediately upon impact. The surface area, as indicated by the pyrometric signals, of the partially molten particles during spreading were almost an order of magnitude smaller than that of the fully molten particles. The pyrometric signals, characteristic of the impact of partially molten zirconia, provide a novel method of identifying partially molten ceramics after impact on a flat surface.


Summary: Photographs and thermal radiation of fully molten and partially molten plasma-sprayed zirconia after impact were gathered. The surface area of the partially molten particles was an order of magnitude lower than that of the fully molten particles. Use of the pyrometric signals will provide a novel method of identifying partially molten ceramics.