Nanoscratch Testing

Introduction to Nanoscratch Testing

Nanoscratch testing is used to measure force response and mechanical properties of mainly thin films and coatings. It can be used for bulk materials analysis as well. A nanoscratch test is done by applying a normal load in a controlled fashion while measuring the force required to move the load tip laterally across the test specimen. Different types of tests can be done by selecting the appropriate normal loading profile and lateral displacement pattern. The damage caused by the scratch test is then typically observed using optical or scanning probe microscopy (SPM) imaging.

In comparison to standard nano-indentation, a more diverse array of deformation and fracture features can be analyzed with nanoscratch testing. The nano-scratch test calibrates and assesses the amount of force necessary to keep the tip moving laterally across the sample surface in addition to standard penetration depth and indent characteristics. 

The specimen’s nanomechanical properties, such as its friction coefficient, adhesion, hardness, and more, are interpolated using an analysis of the tip force, displacement, and optically profiled sample damage.

Strengths of Nanoscratch Testing

Nanoscratch testing is an alternative test to nano-indent or nano-wear box testing. It works on thin films (10 nm and more) and provides advanced mechanical analysis of nano- or micro-scale solids. This test methodology can be used for designing optimized toughness/adhesion tests for thin films 10 nm or thicker. The methodology of nanoscratch testing involves minimal sample preparation and efficient data collection.

Limitations of Nanoscratch Testing

Nanoscratch testing is a destructive technique. This technique is not well suited to measure ultrathin layers (less than 10 nm). Result interpretation might be challenging if films are less than 100 nm and/or the surface is rough. 

Related Techniques

Nanoindentation (Nano-Indent) is a nanomechanical analysis technique used to measure hardness and reduced elastic modulus of solid samples. It is mainly useful for evaluating thin film coatings.