The mechanial properties of surfaces are often different than those of bulk materials. A diamond probe can be used to perform nano-indentations of materials at known normal force in the range of 1 to 100 μN. Knowing the contact area of the nano-indenter and the normal indentation force one can determine a nano-hardness number.
In addition one can study the mode of deformation. This image shows a nano-indentation of glass with a normal force of roughly 10 μN. The pile-up on the side of the indentation is indicative of plastic deformation. These nano-indentations are generally performed in arrays of increasing normal force, or, as in this case, they can be placed at a region of interest. The nano-indentation probe itself is used to image after the indentation so the image quality is slightly reduced.
The top image is the image of a diamond nanoindentation probe. The triangular pyramid of the diamond itself is shown. A stainless steel cantilever extends to the top right of the image. The charging region towards the upper right quadrant is an epoxy used to glue the diamond to the cantilever. The bottom image shows the functional portion of the diamond indentation surface. It was inspected in SEM to ascertain whether the structures visible in optical microscopy near the probe tip were fractures or adhered material. It is clearly debris material from a previous scratch or indentation.
