Characterization and Phase Transformation of Spherical YSZ Powders Fabricated Via air Plasma Spray Method

Air plasma spray (APS) process is used to produce high density and flowability spherical powders. Phase transformation that occurred in this process isn’t well known. In this paper, the YSZ powders have been sprayed in water to investigate the morphology changes and phase transformations via air plasma spray (APS) method. Phase analysis of powders was examined by XRD and the crystallite size and lattice strain of YSZ calculated by the Williamson-Hall method. Morphology and particle size measurement observed by scanning electron microscope. Therefore, results showed the good spherical YSZ powders morphology and amount of tetragonal phase at this process changes from 33 to 47 wt%. that phase transformations were in order to improve the properties of the fabricated powders. Decreasing the crystalline size is due to tetragonal crystallite formation as first monoclinic crystallite (from 91 nm to 70 nm).