Abstract
Thermal nanoparticle spraying has been developed to create fine ceramic layers with a high deposition rate. Micro composite fragments containing ceramic nanoparticles could be successfully introduced into a plasma flame using a conventional powder feeding equipment. Yttria-stabilized zirconia (YSZ) nanoparticles with an average diameter of 200 nm were dispersed in a thermosetting acrylic liquid resin at a volume fraction of 40-60 %. The paste material was placed into a sealed container having an inner capacity of 150 cm3. Dispersing and degassing were performed using a planetary mixer. The mixed paste was solidified by heating at 150°C for 30 min. The composite bulk was crushed using a high-speed vibrating milling machine. The obtained micro composite fragments having particle sizes in the range of 45-106μm were separated by sieving. The moving behaviors of the micro composite fragments in the plasma flame were visualized using a high-speed camera. In the plasma flame, the resin matrix was burned down, and the heated nanoparticles were deposited on a metal substrate. The microstructure of the coated layers was examined using scanning electron microscopy (SEM). The hardness distributions of the coated layers were measured using a micro Vickers hardness tester.
