Evaluation of specific surface area and pore size distribution of la Ni _0.6 Fe _0.4 O ₃ ceramics prepared using Pechini method by N ₂ adsorption method-optimization of sintering temperature as cathode material of solid oxide fuel cells

Sintering temperature dependences of specific surface area, pore size distribution, and pore volume of LaNi_0.6Fe_0.4O₃ ceramics prepared using the Pechini method have been evaluated from the adsorption isotherms of N₂ gas at -195.8°C. The specific surface area decreased almost linearly with increasing sintering temperature showing that preparation of the ceramic specimens with controlled surface area is possible by sintering temperature. The pore size distribution, evaluated by BJH method, showed two peaks around 2.5 and 250 nm with narrow FWHM for the specimen sintered at 900°C. Although both the peaks were maintained in the specimens sintered at 1000°C and 1100°C, their intensity decreased with increasing sintering temperature, indicating decrease of pore volume. It has been revealed that sintering below 1100°C is necessary to prepare LaNi _0.6Fe_0.4O₃ ceramics with pore volume maintained, which is suitable for SOFC cathode material.