Detailed analysis of various artifacts which falsify the hardness measurement by means of load-depth sensing microindentation technique on several micrometers thick coatings is presented and the rules of avoiding them are outlined. A comparison of the results obtained by this carefully verified technique with hardness values calculated from the size of the remaining plastic indentation allowed to confirm the very high hardness of these materials. Analysis of the indentation data within the framework of the Hertzian theory of elastic deformation allowed to further verify the self-consistency of data and estimate the maximum tensile strength and elastic limit of the superhard nanocomposites. The strength of 10-40 GPa compares well with that of the strongest whickers and fibers reported in the literature.
|Number of pages
|Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
|Published - May 2003