Figure 1: Ramped scratches to 500mN show brittle fracture of 1.5 μm TiFeN films on Si at high load.
Thin films and coatings (from a few nm to about 1μm thick) need to be optimised both in the mechanical properties and tribological performance. Typically, this is done with a combination of indentation and scratch tests. Conventional scratch test conditions are not appropriate for these types of materials as they were developed for testing thicker coatings. Instead the nano-scratch & wear module can provide what is needed.
The sample to be tested is moved perpendicular to the scratch probe whilst the contact is either held constant or ramped at a user-defined rate. Throughout the test the probe penetration depth and tangential (frictional) load are continuously monitored. Single and multi-pass tests are possible.
The Nano-Scratch & Wear module has found many applications in sectors as diverse as optical, microelectronics, polymer/biomaterial, and tribological coatings.
Figure 2 shows a scratch test with 3 μm end radius probe scanning over a 150 μm track at a scan speed of 2 μm/s.
A pre-scratch scan was carried out using an ultra low contact force in order to assess baseline sample topography.
The red line shows the on-load probe depth, which represents elastic and plastic depth. After 20μm the load is ramped at 2.5mN/s.
The black line shows the residual (plastic) depth once the scratch load has been removed. This has been corrected for initial sample topography.
Friction measurements are carried out throughout.
Our support literature for Nanoscratch testing will provide a great introduction to the NanoTest Vantage, learn how you could be taking advantage.
