Evaluation of DLC Coating Damage in the Delamination and Wear Test

Diamond-like carbon (DLC) coatings are currently being used in a wide variety of industrial fields because of their outstanding properties such as high hardness and low friction, among others. However, they have a problem regarding adhesion with the base material, which is a major factor hindering their expanded application in other fields. The adhesion of DLC coatings is generally evaluated in the Rockwell test and scratch test. These test methods induce damage in the specimen with applying load by one way or one pass without the cyclic sliding. Accordingly, there is a weak point of low correlation between such test results and evaluations of the adhesion of coatings on components that undergo repeated sliding cycles. With the aim of resolving that problem, this study evaluated the damage condition of DLC coatings using cyclic sliding test methods of applying a continuously increasing load. The evaluation results obtained with these methods differed from the results of Rockwell tests and scratch tests. This paper describes the test procedures and the evaluation results obtained