Direct determination of the area function for nanoindentation experiments

TThe determination of a suitable correction for tip blunting is crucial in order to obtain useful mechanical properties from nanoindentation experiments. While typically the required area function is acquired from the indentation of a reference material, the direct imaging by suitable methods is an interesting alternative. In this paper, we investigate the applicability of confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM), and self-imaging by scanning a sharp silicon tip using the scanning probe microscopy extension of the nanoindentation system and compare the results to the area function obtained by the indentation of fused silica. The important tip characteristics were determined by various methods based on the analysis of the obtained 3D data sets. It was found that the suitability of CLSM and AFM depend on the resolution and the operation mode, respectively. While for these methods only limited consistency of the determined tip characteristics was found, self-imaging resulted in an excellent overall agreement.