Raman Micro‐Spectroscopy of Polytype and Structural Changes in 6H‐Silicon Carbide due to Machining

SiC is an important structural ceramic with many polytypes that differ by the stacking of their crystal planes. Machining mechanically deforms the structure giving stacking faults and different polytypes. This can lead to inferior performance and an increased risk of failure. Raman micro‐spectroscopy with different wavelengths, in confocal and normal settings, was used to quantify machining damage. Changes in the ratio of characteristic peaks, peak intensities versus peak positions, and additional Raman peaks were found. These are due to statistical increases in stacking faults and new phases (4H and 3C). The damage is found to extend several micrometer subsurfaces.