Effects of grinding process on residual stresses in nanostructured ceramic coatings

This paper investigates the depth profiles of residual stresses using the sin2ψ method combined with grazing incident X-ray diffraction (GIXD) technique. It specifically focuses on the effects of grinding process on the residual stresses in the thermally sprayed nanostructured WC/12Co and Al2O3/13TiO2 (n-WC/12Co and n-Al2O3/13TiO2) coatings on low carbon steel substrates. The influence of grinding parameters, such as depth of cut (DOC), table feedrate, abrasive grit size and wheel bond type, on residual stresses is studied. The conditions and limitations of X-ray diffractometry for residual stress measurements are discussed. Discussed also is the difference between the average and actual depth profiles of residual stresses. The paper introduces a method for retrieving the actual depth profiles from the measured average depth profiles. Finally, the influence of peak broadening of grain size, anisotropy from different diffraction planes and surface finish of the samples on the measurement results is explored.