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.