Theory 7
Agilent Nano Indenter G200 User’s Guide
7-29
temperature), extra care must be taken in providing thermal stability
because separation of the thermal displacements from the specimen
displacements is virtually impossible.
Surface Preparation
Surface smoothness is important because contact areas are calculated
from the contact depth and area function rather than observed directly.
Thus, the degree of required smoothness depends on the magnitude of
the measured displacements and the tolerance for uncertainty in the
contact area. As a rule, most deposited films are sufficiently smooth. For
metallographic specimens, a good guide for surface preparation is
ASTM E3-01.
Testing Procedure
To avoid interference, successive indentations should be separated by at
least 20 to 30 times the maximum penetration depth when using a
Berkovich indenter. The importance of frequently testing a standard
material cannot be overemphasized. Whenever the instrument is run, it
is best practice to perform 10 indents on the fused silica standard
provided with the instrument.
