ISO/PWI 12831

Carbon based films — Test method for evaluating adhesion of amorphous carbon thin films by oscillating micro scratch ISO/PWI 12831

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.