Effect of Stabilization of Ionic Conductivity
The addition of yttria to pure zirconia replaces some of the Zr4+ ions in the zirconia lattice with Y3+ ions. This produces oxygen vacancies, as three O2- ions replace four O2- ions. It also permits yttrium stabilized zirconia to conduct O2- ions (and thus conduct an electrical current), provided there is sufficient vacancy site mobility, a property that increases with temperature. This ability to conduct O2- ions makes yttria-stabilized zirconia well suited to use in solid oxide fuel cells, although it requires that they operate at high enough temperatures.
The ionic conductivity of the stabilized zirconias increases with increasing dopant concentration (linearly for low dopant concentrations), then saturates, and then starts to decrease. The maximum ionic conductivity is obtained at Y2O3 concentration of about 8% (1000 °C).
Read more about this topic: Yttria-stabilized Zirconia
Famous quotes containing the words effect of and/or effect:
“To get time for civic work, for exercise, for neighborhood projects, reading or meditation, or just plain time to themselves, mothers need to hold out against the fairly recent but surprisingly entrenched myth that “good mothers” are constantly with their children. They will have to speak out at last about the demoralizing effect of spending day after day with small children, no matter how much they love them.”
—Wendy Coppedge Sanford. Ourselves and Our Children, by Boston Women’s Health Book Collective, introduction (1978)
“As soon as I suspect a fine effect is being achieved by accident I lose interest. I am not interested ... in unskilled labor.... The scientific actor is an even worker. Any one may achieve on some rare occasion an outburst of genuine feeling, a gesture of imperishable beauty, a ringing accent of truth; but your scientific actor knows how he did it. He can repeat it again and again and again. He can be depended on.”
—Minnie Maddern Fiske (1865–1932)