• Same chemistry for one or more crystallographically different phases

• Uncertain chemistry due to particle or grain size

• Overlapping EDS peaks in the spectrum causing uncertainty

EBSD is superior to X-ray powder diffraction because of the inherent advantage in the resolution of electron diffraction relative to X-ray diffraction. In EBSD, diffraction can be considered as originating from a point source at a shallow distance from the surface. The diffraction volume is much smaller than the volume of interaction for X-ray generation. In addition, since EBSD is performed in the SEM, specific microstructural features at submicron levels can be easily identified using the imaging capabilities of the microscope and subsequently analyzed.

A sample EBSD pattern is shown at right. The bands that make up the pattern are directly related to planes in the diffracting crystal lattice and thus provide critical information about the crystal structure in the phase of interest.

> The width of the bands is a function of the lattice spacing.

> The angles between the bands are directly related to the angles between planes in the crystal lattice.

Delphi works on all crystal systems since the combination of band width and interband angles is unique for a particular phase (see seven crystals below).

 
 EBSD diffraction bands

Cubic:Nickel

Hexagonal: Titanium

Monoclinic: Zirconium Oxide

Orthorhombic: Iron Titanium Oxide

Tetragonal: Y123 superconductor

Triclinic: Rhodonite

Trigonal: Quartz