Deposition of porous LSCF films by EAVD method

• Main Authors: Cheng-yun Fu, 傅正允
• Other Authors: Bing-hwait Hwang
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/58552684804346841447

碩士 === 國立中山大學 === 材料科學研究所 === 92 === In this study, a deposition system called EAVD was made to deposite porous LSCF films used as cathode material in the solid oxide fuel cell (SOFC). The relation of deposition parameters to morphology was discussed. Porous La0.8Sr0.2Co0.2Fe0.8O3 films were successfully deposited on Corning glass and ceria substrates, and a pseudo-cubic perovskite phase was obtained after a post-calcination at 750℃ for 2 hrs. Deposition parameters, such as deposition time, deposition temperature, flow rate, voltage applied, different kinds of set-ups (downward spraying or upward spraying), were discussed. The obtained calcined films were characterized by X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDX). On the other hand, surface and cross-section morphology were examined using SEM. In the series using downward spraying system, deposition temperature and deposition time showed profound effect on morphology. With increasing the extent of these two factors, porous films were obtained. With decreasing the extent of these two factors, however, dense films were obtained. The effects of other parameters to morphology were less obvious. Under proper conditions, cauliflower-like films with high porosity were obtained. In the series using upward spraying system (vertical set-up), reticular films were successfully obtained using deposition temperature ranging from 275~320℃, flow rate 1.0~1.5 ml/hr, and deposition time within 2 hrs. In the series of flow rate, the pores of reticular structure seemed to grow up with increasing flow rate. Under the condition of prolonged deposition (4 hrs), a stalactitc structure with micropores on it was obtained. The highly porous structures obtained in this study are very suitable for applications in gas sensor and electrodes in SOFC.