Sample Preparation for EBSD

Grinding the Sample

Coarse Grinding

Grinding can be achieved in a variety of ways, using a variety of abrasives. Fixed abrasive surfaces are available using diamond or cubic boron nitride (CBN) abrasives. The method used to bind the abrasives to the wheel affects the grinding characteristics, the harder or more rigid the bonding medium, the more aggressive the grinding action of the surface. Therefore metal bonded fixed abrasive wheels are the most aggressive grinding surfaces, whereas resin bonded wheels are less aggressive.

Coarse grit Silicon Carbide or Alumina abrasives may be used, but the durability or characteristics of such materials may be inappropriate for certain materials. Generally, in order to maintain sharp abrasive particles, grinding papers need frequent changing.  Follow the manufacturer’s recommendations and advice.

Fine Grinding

Silicon Carbide (SiC) paper is the traditional method used for fine grinding and is adequate when used properly.   SiC paper blunts quickly and therefore should be discarded after a short period of grinding in order to maintain efficient 'stock' removal.  Grinding on a surface that has blunt abrasives causes a great deal of surface damage by smearing, 'burnishing' and local heating.

Ensure that sharp abrasives are used and follow the manufacturers' instructions with regard to grinding speeds, direction, force, times and lubricants used. Damage injected during grinding may be invisible in the polished surface,  but serve to distort the EBSD result or even completely suppress pattern formation.   Remember that different materials have different abrasion characteristics.  The selection of grinding material and conditions can therefore be specific to a given sample.

After every grinding stage it is advisable to inspect the ground surface using a light microscope in order to ensure that all damage from the previous stage, whether that be a cutting or grinding stage, is completely removed.  Advance in this manner to the finest abrasive size required, ready for polishing.   Care at this stage will greatly reduce the amount of polishing required to achieve a good surface.