The Grain Size Effect on the Yttria Stabilized Zirconia Grain Boundary Conductivity

The grain size dependence of the bulk resistivity of 3 mol% yttria-stabilized zirconia at 1400°C was determined from the effect of a dc electric field Ea=18.1 V/cm on grain growth and the corresponding electric current during isothermal annealing tests. Employing the brick layer model, the present annealing test results were in accordance with extrapolations of the values obtained at lower temperature employing impedance spectroscopy and 4-point-probe dc. The combined values give that the magnitude of the grain boundary resistivity ρb=133 ohm-cm. The electric field across the grain boundary width was 28–43 times the applied field for the grain size and current ranges in the present annealing test.

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Nanostructure, Nanochemistry and Grain Boundary Conductivity of Yttria-Doped Zirconia

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.106.83 ◽

2005 ◽

Vol 106 ◽

pp. 83-86

Author(s):

A. Rizea ◽

Jean Marc Raulot ◽

C. Petot ◽

Georgette Petot-Ervas ◽

Gianguido Baldinozzi

Keyword(s):

Grain Boundary ◽

Beneficial Effect ◽

Grain Boundaries ◽

Strong Interaction ◽

Glassy Phase ◽

Yttria Stabilized Zirconia ◽

Stabilized Zirconia ◽

Boundary Conductivity ◽

Comprehensive Study

This work was directed at a comprehensive study of the role of the nanostructure and nanochemistry on the transport properties of yttria-stabilized zirconia. Alumina additions lead to a decrease of sgb when the samples have clean grain boundaries, while sgb goes through a maximum in samples having glassy grain boundaries. The differences were attributed to the strong interaction between Al2O3 and SiO2 impurities leading to a glassy phase depletion at the grain-boundaries, due to a change in wettability. Moreover, XPS analyses show that Si and Y segregate near these interfaces according to a kinetic demixing process, explaining why a faster cooling rate after sintering has a beneficial effect on sgb.

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Analytical TEM study of a yttria stabilized zirconia/glass composite

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104923 ◽

1988 ◽

Vol 46 ◽

pp. 572-573

Author(s):

Yung-Jen Lin ◽

Peter Angelini ◽

Martha L. Mecartney

Keyword(s):

Grain Size ◽

Grain Boundary ◽

Grain Growth ◽

Room Temperature ◽

Tetragonal Zirconia ◽

Yttria Stabilized Zirconia ◽

Boundary Phase ◽

Stabilized Zirconia ◽

High Toughness ◽

M Phase

Yttria stabilized zirconia is a versatile ceramic material. It can be used for structural components or as a solid electrolyte. Its properties (such as high toughness) are strongly affected by the microstructure. In partially stabilized zirconia, the high toughness is mainly due to the toughening effect of a tetragonal (t) to monoclinic (m) phase transformation in the vicinity of a crack. Retention of tetragonal zirconia at room temperature is important for fabricating transformation toughened materials. To completely retain tetragonal zirconia at room temperature the grain size of the material must be less than a critical size. In yttria stabilized zirconia this critical grain size depends on the yttria concentration. Grain growth of yttria stabilized zirconia is also influenced by the amount of yttria in the grains. These previous studies, however, have focused on the behavior of materials with minimal glassy grain boundary phases. In contrast, in commercial polycrystalline zirconia often a significant amount of glassy grain boundary phase is present. This current research seeks to elucidate the effects of these grain boundary phases on the grain growth in yttria stabilized zirconia ceramics.

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