One-step fabrication of tetragonal ZrO2 particles by atmospheric pressure plasma jet

A novel atmospheric pressure plasma jet (APPJ) was applied to prepare the tetragonal zirconia particles via a solution of zirconyl (IV) nitrate hydrate (ZrO(NO3)2‧xH2O) as the precursor. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The microstructure of zirconia was found to be an assembly of spherical particles with a tetragonal structure. The chemical composition of prepared zirconia particles was analyzed by XPS quantification study with an atomic ratio of O/Zr of 2.03 without nitrate residues. The results based on the one-particle-per-drop mechanism in an APPJ system also showed that the synthesis of tetragonal zirconia particles could be effectively achieved in one-step fabrication without the need for additional stabilizers or annealing process. Meanwhile, APPJ system has a great potential to be a cost-effective and time-saving process for particle production as compared to the wet chemical processes.