Electrostatic spray deposition of La0.8Sr0.2Co0.2Fe0.8O3 films

• Published in: Materials chemistry and physics 2005-05, Vol.91 (1), p.28-35
• Main Authors: Fu, Cheng-Yun, Chang, Chin-Liang, Hsu, Ching-Shiung, Hwang, Bing-Hwai
• Format: Article
• Language: English
• ISSN: 0254-0584
• DOI: 10.1016/j.matchemphys.2004.10.041

As an efficient energy-conversion and environmentally friendly technology, solid oxide fuel cells have attracted much attention. Although significant progress has been made, SOFCs have stil failed to reach widespread commercial viabiity due to long-term degradation problems, originating from the thermal mismatch among electrolyte, cathode, anode, and inter-cell connectors. La0.8Sr0.2Co0.2Fe0.8O3 films were successfully deposited on stainless steel and glass substrates using electrostatic spray deposition (ESD) method. Metal nitrates were dissolved in the mixture of 75vol.% ethanol and 25 vol.% distilled water to prepare starting precursor solution. Thermogravimetry (TG) measurement indicated that evaporation of solvent and decomposition of complexes of precursors were largely finished below 350 deg C. The as-deposited films were amorphous. After a calcination of 750 DGC/2h, the deposited films crystallized to form perovskite crystals, as revealed by X-ray diffraction (XRD). Morphology observation by scanning electron microscope (SEM) indicated that much higher porosity in the films were obtained when the deposition temperature was raised from 150 to 350 deg C. Similar trends were observed with increasing deposition time, increasing substrate roughness and decreasing electrostatic field strength, although to a lesser degree. These trends are explained by the mechanism of preferential landing of aerosol droplets and agglomeration of particles under different deposition conditions. The compositions of the deposited and then calcined films were in fairly good agreement with that of the starting solution. Porosity of a 350 deg C-deposited and then calcined film was estimated at about 55%.