Investigation of grain-boundary geometry and pores morphology in dense and porous cubic zirconia polycrystals

• Cubic zirconia sinters were investigated in three dimensions using dual-beam FEGSEM.
• The 3D-EBSD technique was successfully applied to non-conductive ceramics.
• New sample preparation approach to automated 3D-EBSD was proposed.
• Grain boundary microstructures were reconstructed from inverse pole figure maps.
• Pore microstructures were reconstructed from image quality maps.

Three-dimensional electron backscatter diffraction technique was used for the visualization of grain boundary geometry and pore morphology in cubic zirconia. A set of four samples sintered under different conditions was investigated. Specimens which were characterized by energy dispersive spectroscopy and X-ray diffraction were entirely composed of cubic phase. Investigations of boundaries and pore structures were carried out in a dual-beam scanning electron microscope. For each sample, a volume of 1000 μm3 was investigated. The analysis of grain boundary networks reconstructed from inverse pole figure maps revealed a strong dependence between grain boundary density and sample preparation parameters. Sintering also affects the size and distribution of pores. The total number of grains analyzed varied from 17 to 357 and the calculated volume of cavities from 0.01% to 21%. This paper shows the application of three-dimensional crystallographic orientation analysis to characterize the microstructure of yttria stabilized zirconia ceramics.

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