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EBSD Microstructural Characterisation of an Alumina Insulator

The excellent mechanical and electrical properties of engineering ceramics make them popular in a wide variety of applications. In this example, the high dielectric strength of alumina promotes its use as an electrical insulator. These dielectric properties are influenced by the porosity of the material, which needs to be kept to a minimum after sintering to ensure optimum performance. The properties are engineered by controlling the grain size of the raw material and by the use of various additives.

Therefore, characterisation of the ceramic microstructure is vital in understanding and controlling its properties and Electron Backscattered Diffraction (EBSD) is the ideal technique for this. Typically the properties of interest include:

  • Grain size and shape
  • Grain boundary characterisation
  • Porosity
  • Texture
  • Phase identification (when used in conjunction with EDS).

This data is typically presented in the form of maps and pole figures.

Sample preparation of ceramics can be more challenging than for metallic materials, but standard preparation techniques can be successful in producing sample surfaces suitable for EBSD.

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