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A comparative study has been carried out on the effects of pore-forming agents on the microstructural characteristics and properties including porosity, microstructures, linear sintering shrinkage and mechanical strength of NiO/yttria stabilized zirconia (YSZ). Different pore-forming agents (soluble starch, graphite and activated carbon) were incorporated into NiO/YSZ at various mass mixing ratios (5%, 10% and 15%). The experimental results show that under the condition of same content, sintered samples using activated carbon as pore-forming agent had a higher porosity than that with identical content of the other two kinds of pore-forming agents. Sintered samples with 10.0 wt% activated carbon had a porosity of 35%. Section morphologies show that pores distributed uniformly and connected very well in the anode with activated carbon as pore-forming agent. The mechanical strength of these sintered samples with carbon as pore-forming agent was also higher. With the activated carbon particle size decreasing (from 100 mesh to 320 mesh), the open porosity of porous NiO/YSZ was reduced (from 31.7% to 30.9%). It may be concluded that The activated carbon is the better choice as pore-forming agent for NiO/YSZ anode.

Different contents of bismuth oxide doped in 3YSZ material and the mixed powder formed. After press forming,the samples were sintered at 850°C, 900°C, 1000°C and 1100°C respectively. The electrical properties,the thermal shock resistance,the phase components and the microstructure morphology were analyzed to study the solid solution mechanism of Bi2O3-Y2O3-ZrO2 three-phase system. It was found that the Bi2O3 can effectively reduce sintering temperature as a flux. Sintered at 1000°C, t-ZrO2 can be induced into m-ZrO2 by Bi2O3 doped. With the increasing of Bi2O3 content, system shock resistance decreases. The thermal shock resistance of the 2-3mol% Bi2O3-YSZ is the best. In the different content of Bi2O3 system, 3mol% doped materials has the highest conductivity.