LOW LOAD VICKERS HARDNESS MEASUREMENTS OF NONCONDUCTING MATERIALS IN A SCANNING ELECTRON MICROSCOPE.

Vickers hardness tests on microscopic small bodies, e. g. , fibers, powder particles, thin layers, etc. , require imprint dimensions near or even below the resolution limits of light microscopes. Hence, to detect and evaluate these miniature imprints a scanning electron microscope (SEM) has to be used. For such observations in a SEM, nonconducting samples have to be coated with a thin conductive layer. The influence of these films on the imprint size and thus on the hardness value can be rather significant. On the basis of a systematic investigation in the case of a layer much softer than the sample to be tested, methods for an elimination of the layer's contribution to the hardness result are presented.