Large scale synthesis of non-transformable tetragonal Sc2O3, Y2O3 doped ZrO2 nanopowders via the citric acid based gel method to obtain plasma sprayed coating

Non-transformable tetragonal scandia, yttria doped zirconia (SYDZ) nanopowders were prepared in large scale by the citric acid (CA) based gel method. The effect of ethylene glycol monobutyl ether (EGM):CA ratios and pH on the structure, morphology and SYDZ particle size was investigated. The microstructure of SYDZ was characterized by XRD, Raman scattering, TG-DTA, SEM, TEM, and FTIR analyses. The SYDZ nanopowders, synthesized with 1Zr4+:4EGM:4CA mole ratio in acidic medium (pH ∼1) at 700 °C, had an average diameter of 15±2 nm. Finally, air plasma spray (APS) coatings were produced from nanostructured SYDZ agglomerated powders.