Investigations of Apatite-Structure Coatings Deposited by Reactive Magnetron Sputtering Dedicated to IT-SOFC

Apatite La9.33Si6O26 coatings were co-sputtered on rotating substrates from metallic La and Si targets in the presence of a reactive argon-oxygen gas mixture or in pure argon. This material is a potential candidate as electrolyte material for intermediate temperature-solid oxide fuel cells (IT-SOFC). The structural and chemical features of these films have been determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is shown that the as-deposited metallic or ceramic coatings, initially amorphous, crystallise in apatite structure as a function of their composition after annealing (and oxidising) treatment under air beyond 973 K.