Theory 7
Agilent Nano Indenter G200 User’s Guide 7-4
Note that S has the dimensions of force per unit distance, and so it is
also known as the elastic stiffness of the contact.
Figure 7-2Schematic of Load-Displacement curve
Hardness
The hardness (H) of the test surface is determined using the equation:
H = P/A (5)
where P is the load applied to the test surface, and A is the projected
contact area at that load.
Elastic Modulus
The elastic modulus (E) of the test sample is determined from the
reduced modulus, E
r
, given by:
(6)
E
r
S
2 A
----------------=