Optical absorption in current-blackened yttria-stabilized zirconia

Transparent Nanometric Cubic and Tetragonal Zirconia Obtained by High‐Pressure Pulsed Electric Current Sintering

“…When exposed to a reducing environment at high temperatures, cubic and tetragonal zirconia can develop high concentrations of point defects, in the form of oxygen vacancies. [35][36][37][38][39] Furthermore, in the presence of impurities of transition metal oxides, small metal clusters can also develop, forming metal colloids that are characterized by very strong light absorption. Such an occurrence has been reported in the case of carbothermal reduction of zirconia single crystals with the formation of metal clusters with a dimension between 10 and 100 nm.…”

“…More complex associations, involving the atoms of the dopant element V O Y ′ ZR x , usually indicated with the symbol F A ) have also been proposed. [34,35] Color centers are characterized by very strong absorption coefficients. Carbothermally reduced single crystals showed the evidence of F center formation in YSZ by two typical features in the optical pattern: a shift towards shorter wavelength of the natural absorption edge of zirconia, placed at approximately 290 nm, and the appearance of several broad absorption bands, the most intense being located at approximately 480 nm.…”

“…Carbothermally reduced single crystals showed the evidence of F center formation in YSZ by two typical features in the optical pattern: a shift towards shorter wavelength of the natural absorption edge of zirconia, placed at approximately 290 nm, and the appearance of several broad absorption bands, the most intense being located at approximately 480 nm. [35][36][37][38][39] This band is responsible for the yellowish-brown coloration observed in the reduced samples. Color centers in zirconia can usually be annealed out in air or oxygen atmosphere at moderated temperatures.…”

Interfacial Resistivity of Yttria Stabilized Zirconia in Operating Solid Oxide Fuel Cells

“…The very small AC currents used by EIS minimize the current-induced reduction of YSZ that can be observed with the higher currents used in traditional four-probe measurements of material resistivity. (15)(16)(17) ECS Transactions, 11 (27) 111-120 (2008) H 2 was used as the fuel for these experiments and all cells operated at a temperature of 775 °C. A 70 sccm flow of H 2 on the anode side was balanced by a 35 sccm flow of air on the cathode side.…”

Enhancement of paramagnetic defects in yttria stabilized zirconia implanted by Cs ion irradiation

“…EPR was usually used to study irradiation damage in crystals and glasses, such as, the defect structure of amorphous silicon produced by Kr, Au, He and Si ion implantation into silicon was shown that "dangling bond" paramagnetic center (or D center) [16][17][18] and the irradiation damage of glasses and nuclear glasses by ␤-, X-and ␥-ray radiation and heavy ion radiation [19][20][21]. During the past 10 years, the several works on the specific structures and possible defect configurations of the optical active defects in single crystal YSZ were carried out, [22][23][24] mainly with EPR spectroscopy. The correlations between EPR and optical-absorption signals in differently treated samples (chemically and electrically reduced, [24,26] X-ray-and UVirradiated, [28,29] thermally and photobleached [30,31]) pointed to the clarification of the origin of the optical properties in the visible and near UV spectral region [24,25,28,32].…”