Nanoindentation with a Knoop indenter

Nanoindentation is a reliable method for measuring mechanical properties of thin films and small volumes of most materials. The Berkovich indenter is preferred for measurement of hardness and Young's modulus at the very low loads at which the Nanoindenter^TM is capable of operating. For specialized tests, other tip geometries such as a Knoop indenter may be advantageous. This study concerns itself with the comparison of ultra low-load Knoop to Berkovich indents on 6061 aluminum, silicon, aluminum oxide, fused silica, nickel and silicon nitride. Values for material hardness obtained from the indentation loading and unloading history of silicon and 6061 aluminum from barstock were compared to values for hardness calculated by measuring the residual indenter impressions on scanning electron microscope images. Results based on measurements and characterization of residual indenter impressions indicate that the response of materials to Knoop indentation is comparable to other indenters.