Preparation and characterization of nanostructured ceramic coatings obtained by suspension plasma spraying

This work proposes a study on the elaboration and characterization of nanostructured ceramic coatings obtained by a non-conventional method, suspension plasma spraying. This technique allows the feeding of fine nano- and submicron-particles in the enthalpic plasma and offers the possibility to preserve the original crystalline structure, avoiding the undesired phase transformations in the ceramics, which generally takes place in thermal spraying. TiO2 and Al2O3 suspensions were fed at atmospheric pressure by aid of a peristaltic pump in a special designed injector that ensured the atomization and the radial injection of the suspension into the plasma jet. Morphology and crystalline structure of the suspension sprayed-coatings were mainly studied by scanning electron microscopy and X-ray diffraction. The aim of this work consisted in a comparative study and discussions coatings properties as a function of suspensions and plasma spraying plasma parameters.