Observations on abrasive wear damages on engineering ceramics using micro-Raman tomography

In this paper, we apply micro-Raman tomographic imaging (mRTI) method on surfaces of the engineering ceramics with abrasive wear for evaluating the surface quality, aiming to the applications in failure analysis of the ceramic components, development of the abrasive machining and inspection techniques of the ceramics products. Observations of subsurface damage were successfully conducted on single crystal materials such as sapphire (single crystal of α-Al2O3) using mRTI due to the transparency of the material. We attempt to measure the surface of alumina ceramic plates using mRTI. Since light diffusion due to grains of the polycrystal substance and surface roughness disturbs the measurement, we utilized the surface smoothing and oil immersion measurement to reduce scattering. On the measurements of abrasive polished surface, extracted peak feature values of typical Raman peak at 417 cm-1 such as the peak shift, peak width and peak intensity are imaged as the distribution of the damage by abrasive wear like tomographic measurement. The wear damages expanding to more than 10 micron-depth beneath the surface are visually recognizable in the image.