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Articles you may be interested inOptical properties of Nd 3+ ions in oxyfluoride glasses and glass ceramics comparing different preparation methods J. Appl. Phys. 95, 5271 (2004); 10.1063/1.1707204 Site selective study of Eu 3+ -doped transparent oxyfluoride glass ceramics J. Appl. Phys. 94, 2295 (2003); 10.1063/1.1592298Highly efficient green up-conversion luminescence of Nd 3+ -Yb 3+ -Ho 3+ codoped fluorite-type nanocrystals in transparent glass ceramics

The accelerated degradation by impurities was investigated at cathodes with flowing CrO 3 and SO 2 gases. Relatively high pressures (p~10 -8 -10 -4 atm) of CrO 3 and SO 2 were applied to the cathodes and the degradation behaviors were investigated as a function of operation time. The degradation mechanism was examined by considering chemical reactivity and electrochemical reaction at the active cathode/electrolyte interfaces. In the case of CrO 3 poisoning, the relationship between the deposited Cr 2 O 3 amounts and degradation rates of cathode performance was different with cathode materials and polarization. In the case of SO 2 poisoning, the chemical reactivity of cathodes changed the performance by forming the Sr-Sulfate on the surface. The accelerated degradation enabled us to estimate the life time of cathode within a short period of time.

The effect of polarization on platinum deposition from current collector to triple phase boundaries around LSM/YSZ interfaces was investigated. Button-type half-cells consisting of LSM cathode and 8YSZ electrolyte with platinum mesh current collector was used for polarization tests at T = 1073 K. Fixed voltages of - 0.1 or -0.3 V vs. reference electrode was applied to the cathode during the tests. Abnormal rapid increment of current density was observed at the large polarization of -0.3 V, and normal slow increment of current density was observed at the small polarization of - 0.1 V. Platinum particles are observed at the triple phase boundaries (TPBs) around LSM/YSZ interfaces after the cell test at - 0.3 V for 60 h. On the other hand, platinum particles are not observed around TPBs after the cell test at - 0.1 V for 86 h.

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