ISO/PWI 12831

Carbon based films — Test method for evaluating adhesion of amorphous carbon thin films by oscillating micro scratch

Scope

This document specifies the oscillating micro scratch test for evaluating the adhesion of thin films of amorphous carbon (diamond-like carbon, DLC) with a thickness of 1 µm or less, which is formed on a substrate. The oscillating micro scratch test is based on the scratch test stipulated by ISO 20502 and is a testing method suitable for evaluating the adhesion of thin films. In this test, the adhesive and/or cohesive failure of the specimen is detected by the change of signal gained with the oscillating stylus. The oscillating stylus (hereinafter referred to as “sensor”) is oscillated with a predetermined amplitude on the specimen surface with repeated loading, and results in data that are equivalent to the friction force. Similar to a conventional scratch test, the signal will change when the film failure occurs. Compared to the scratched track observed with a microscope, the normal force that indicates the film failure is recorded as a critical normal force. In comparison with critical normal forces for several specimens, adhesion of amorphous carbon thin films is evaluated.