Alumina-Titania Spot Spraying Bead Formation and Characteristics in Atmospheric Plasma Spraying

Fine and coarse alumina-titania composite particles were overlaid by allowing the particles to be deposited for a short time without moving a plasmatron [spot spraying bead]. Both the deposition efficiency and maximum deposition rate were measured at the different plasma gas composition. Considering the normalized maximum deposition rate [(maximum deposition rate)x(deposition efficiency)-1], effects of particle size and plasma gas composition on the particle segregation within a cross-section of mass flux could be estimated. Also, particle melting state according to the position within a mass flux at the moment of impact could be also estimated through the investigations of microstructure and phase composition of the spot spraying bead.