要約

The deposition of complex oxide layers for Solid Oxide Fuel Cell membranes (SOFC) or Thermal Barrier Coating (TBC) in gas turbines is a current subject of investigation. A low pressure plasma reactor was developed to very quickly and easily deposit thick oxide coatings presenting various compositions. The reactor is equipped with an injection system which enables the introduction of nitrate salts dissolved in aqueous solution under a spray form into the reactor. The velocity and the diameter of the droplets of the spray were measured on line by using a particle dynamics analyser coupled with the plasma reactor. Droplet velocity of more than 30 m. s^{−1 was measured at the exit of the nozzle. Optical emission spectroscopy showed that the high vaporization of water from droplets observed by the particle dynamic analyser was a favorable feature for the production of OH° radicals due to the dissociation of H₂O in the discharge. Infrared spectroscopy confirmed that O and OH° were responsible for the transformation of nitrates into solid oxide at low temperature. The morphologies of ZrO₂-Y₂O₃ coatings (YSZ 4% mol of Y) and Ba₃MgTa₂O₉ for TBC application obtained after optimizing plasma parameters have been characterized by scanning electron microscopy.}