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Tuesday, October 28, 2008
Exhibit Hall
A Co-Ni coated stainless steel mesh was applied for cathode current collectors in ASC-type planar SOFC instead of noble metals such as Pt and Ag. Crofer22 APU was selected as a stainless steel mesh, and Co-Ni was deposited on Crofer22APU substrate in a hydrazine-based electroless coating solution. The thickness of Co-Ni layer was approximately 1㎛, and the compositions in Co-Ni coating layer was composed of 70wt% Ni and 30wt% Co.
Before SOFC single cells with Co-Ni coated stainless steel mesh being operated, some prior tests were conducted in order to evaluate characteristics of the coated and uncoated specimens in advance. First, ASR(area specific resistance)s of plate specimen(3X3cm2) were measured after oxidation at 800℃ in air for 100hrs. The Co-Ni coated specimen showed a better electrical performance than that of bare crofer22APU. Second, Cr-evaporation rates of specimens were measured in air with 3%H2O at 800℃ by a transpiration method. The Cr-evaporation rate of Co-Ni coated specimen decreased dramatically due to the formation of an outer Co-oxide.
After these prior tests, performances of ASC-type planar (10X10cm2) SOFC’s were investigated with 3 different cathode current collectors such as bare crofer22APU, Co-Ni coated crofer22APU and Pt mesh. The single cell with the Co-Ni crofer22APU mesh showed about 90% of power density compared with that of Pt mesh under the current density of 0.5A/cm2 at 750℃, while the uncoated crofer22APU mesh recoded about 75% of the power density.
Before SOFC single cells with Co-Ni coated stainless steel mesh being operated, some prior tests were conducted in order to evaluate characteristics of the coated and uncoated specimens in advance. First, ASR(area specific resistance)s of plate specimen(3X3cm2) were measured after oxidation at 800℃ in air for 100hrs. The Co-Ni coated specimen showed a better electrical performance than that of bare crofer22APU. Second, Cr-evaporation rates of specimens were measured in air with 3%H2O at 800℃ by a transpiration method. The Cr-evaporation rate of Co-Ni coated specimen decreased dramatically due to the formation of an outer Co-oxide.
After these prior tests, performances of ASC-type planar (10X10cm2) SOFC’s were investigated with 3 different cathode current collectors such as bare crofer22APU, Co-Ni coated crofer22APU and Pt mesh. The single cell with the Co-Ni crofer22APU mesh showed about 90% of power density compared with that of Pt mesh under the current density of 0.5A/cm2 at 750℃, while the uncoated crofer22APU mesh recoded about 75% of the power density.