Session *BB3.5

10:45 AM *BB3.5
IMPROVED THERMAL SPRAY PROCESSES FOR PRODUCTION OF COMPLEX MULTILAYER STRUCTURES. Rudolf H. Henne, Institute für Technische Thermodynamik, DLR-Stuttgart, Stuttgart, GERMANY.

One of the most challenging tasks for thermal spray technology represents at present the fabrication of the very complex mulilayer structure of solid oxide fuel cells (SOFC) by thermal spray processes. SOFCs can play an important role in future energy field as very efficient and environmentally friendly direct converters of chemical into electrical energy. Main precondition for a wide spread application of SOFCs is besides high power density, high reliabilty and long life time their economic production with low cost materials and processes. The core of a SOFC - the MEA, the membrane-electrodes assembly, consists in general of a material and porosity graded Ni-ZrO2 cermet anode, a doped, thin, but gas tight ZrO2-electrolyte as oxygen-ion conductor, and an oxide cathode of perovskite material, again porosity graded. Improved and specially adapted DC and RF plasma spraying shows a high potential to meet this demands and to be able to make such complex structures in an economic and consecutive multistep process. The presentation will mainly concern the required and performed adaptation of the DC and RF plasma spraying processes, especially the modification of torch nozzles and of the parameters for improved and controlled plasma flow and plasma - spray particles interaction and for the involvement of required plasma chemical effects in the spray process.