Study of α-Fe2O3 formation and its measurement in oxide films of wheel surface during ELID grinding process

Abstract

This paper presents the study of forming mechanism of [Formula: see text]-Fe2O3 in oxide films on electrolytic in-process dressing (ELID) grinding wheel surface. To investigate the component content and the microtopography of oxide films, XRD, XPS, IR spectrum analysis, SEM, and TEM measurements are performed on ELID grinding wheels. In XRD test results, the characteristic absorption band of [Formula: see text]-Fe2O3 is found in the oxide film. XPS tests show that there is full of ferrous iron and oxygen element in the oxide film. Also, the characteristic spectral line of XPS is identical to the standard spectrum of [Formula: see text]-Fe2O3. Several vibration peaks (471, 1029, 1384, 1630, 3430) are observed by IR spectrum analysis. It can be easily seen by contrast with the standard photographs that the vibration peak of 1029 is of Fe-O vibration band in IR spectrum of [Formula: see text]-Fe2O3 powder. Therefore, these measurement results confirm the existence of [Formula: see text]-Fe2O3 in the oxide films, and explain the polishing effect of oxide films during ELID grinding. The fresh oxide film is porous and moisture rich. However, the oxide film after squeezing to dry is investigated by SEM imaging to present tortoiseshell cracks. Geometrically, [Formula: see text]-Fe2O3 appears to be nearly spherical with particle size around 5–50 nm. This indicates fine polishing improvement by oxide films, and is identified as the mechanism responsible for excellent surface quality by ELID grinding.