Electron microscopy
 
Yttria-Stabilized Zirconia (YSZ)
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Yttria-stabilized zirconia (YSZ) is a ceramic in which the crystal structure of zirconium dioxide becomes stable at room temperature by adding yttrium oxide to. These oxides are named because of the origin of "zirconia" (ZrO2) and "yttria" (Y2O3).

Some of the abbreviations commonly used are as follow:
        i) Partly stabilized zirconia ZrO2:
           i.a) PSZ - Partially Stabilized Zirconia
           i.b) TZP -Tetragonal Zirconia Polycrystal
           i.c) 4YSZ: with 4 mol-% Y2O3 partially Stabilized ZrO2, Yttria Stabilized Zirconia
        ii) Fully stabilized zirconias ZrO2:
           ii.a) FSZ - Fully Stabilized Zirconia
           ii.b) CSZ - Cubic Stabilized Zirconia
           ii.c) 3-12YSZ - with 3-12 mol-% Y2O3 Stabilized ZrO2

Figure 3312 shows the Z-contrast image of a symmetric 24° [001] tilt grain boundary in YSZ (yttria-stabilized zirconia), the schematic of the grain boundary structure and the EEL spectra from the bulk and grain boundary after removal of EELS background. Table 3312 lists the material properties which has been extracted from the EELS profiles. These properties may cause an increase of the number of electrons in the conduction band at the grain boundaries.

YSZ (yttria-stabilized zirconia)

Figure 3312. (a) Z-contrast image of a symmetric 24° [001] tilt grain boundary in YSZ (yttria-stabilized zirconia), (b) schematic of the grain boundary structure, and (c) EEL spectra from the bulk and grain boundary after removal of EELS background. [1]

 
Table 3312. Material properties which has been extracted from the EELS profiles.
  Property of grain boundary
M2,3 of Y 1.5 eV shift to higher energy than bulk, indicating an increase in the number of electrons in the boundary plane
M2,3 of Zr
O K near-edge structure A change of O K near-edge structure indicates the distortion of cubic symmetry at the grain boundary
M3/M2 ratios of Zr Larger than bulk, indicating an increase in the number of electrons in the boundary plane
M3/M2 ratios of Y
Y/Zr ratio Larger than bulk
O/Zr ratio Smaller than bulk
O/Y ratio

 

 

 


[1] Y. Ito, Y Lei, N.D. Browning and T.J. Mazanec, Analysis of the Atomic-Scale Defect Chemistry at Interfaces in Fluorite Structured Oxides by Electron Energy Loss Spectroscopy, Mat. Res. Soc. Symp. Proc. Vol. 703, 489 (2002).


 

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