A full factorial design of 24 experiments was used to determine the effects of four principal plasma spray parameters (i.e., plasma forming
gas composition, electric power, spraying distance, and carrier gas flow rate on the microstructure of hydroxyapatite (HA) coatings and
powders). The granulometry of powders was tested after spraying into water and compared to the initial one. The crystal phase content of
powders and coatings was determined using quantitative X-ray diffraction (XRD) analysis. The morphologies of coatings surfaces, crosssections,
and particles sprayed into water were characterized using scanning electron microscopy (SEM). The mapping of elements inside
plasma-treated powders was carried out using electron microprobe analysis (EMPA). Infrared spectroscopy (FTIR) allowed determination of
the dehydration of HA under different spray conditions.