Imaging and Quantitative Evaluation of Micro-Crack Density in Chromium Coatings on Steel by Means of Acoustic Microscopy

A non-destructive method of high frequency acoustic microscopy (HFAM) is applied to image and quantify micro-cracks in approximately 10 urn thick hard chromium coatings, especially in-depth where conventional reflected light and scanning electron microscopy (RLOM and SEM) are inadequate. Detailed information on precise in-depth micro-crack geometry and position is gained. The extension of this method leads to a study of adhesive failure (interface cracks).