Theory 7
Agilent Nano Indenter G200 User’s Guide
7-8
Determining Contact Stiffness Dynamically
It is important to note that in general, the contact stiffness,
S
, is required
for the determination of elastic modulus and hardness because it is used
in the calculation of the projected contact area,
A
. The Continuous
Stiffness Measurement (CSM) option allows the continuous
measurement of the contact stiffness during loading and not just at the
point of initial unload. This is accomplished by superimposing a small
oscillation on the primary loading signal and analyzing the resulting
response of the system by means of a frequency-specific amplifier. With
a continuous measure of S, one obtains the hardness and elastic modulus
as a continuous function of depth from a single indentation experiment.
Theory and details of operation are provided with the documentation for
the CSM option in