Grain size quantification by optical microscopy, electron backscatter diffraction, and magnetic force microscopy.

Quantification of microstructure, especially grain size, in polycrystalline materials is a vital aspect to understand the structure-property relationships in these materials. In this paper, representative characterization techniques for determining the grain size, including optical microscopy (OM), electron backscatter diffraction (EBSD) in the scanning electron microscopy (SEM), and atomic force microscopy/magnetic force microscopy (AFM/MFM), are thoroughly evaluated in comparison, illustrated by rare-earth sintered Nd-Fe-B permanent magnets. Potential applications and additional information achieved by using aforementioned characterization techniques have been discussed and summarized.