Suggestion of Evaluation method for Adhesion of DLC Films Using Scratch Test and 180 Degree Bend Test
Morimasa NAKAMURACKen-ichi MIURA, Takashi MATSUOKA and Tomoko HIRAYAMA
Abstract:A new formula to calculate Adhesion energy W of DLC films was suggested on the base of Bullfs model using Critical load Lc by scratch test in consideration of compressive residual stress Ðres in the film. Beside, a new Adhesion parameter J indicating Adhesion energy of the film was derived using fractured area ratio Rb by 180bend test. Further, with DLC films practically deposited on SUS304 under the various deposition conditions by UBM sputtering, Lc by scratch test, Ðres by substrate curvature measuring test, Youngfs modulus EF by nano-indentation test, and Rb by 180bend test were obtained. Validity of these formula and parameter for Adhesion energy were assessed by evaluating changes in Lc, Ðres, EF, Rb, W, and J with deposition conditions of the DLC films. Critical load Lc by scratch test changed significantly depending on the changes in mechanical property of EF, and Rb by 180bend test changed with film thickness, were considered to be unreasonable as evaluating of film adhesion. While Adhesion energy W and Adhesion parameter J calculated by the formula suggested in this paper had a proportional relationship regardless of the deposition conditions. Both W and J were concluded to be derived appropriately for the evaluation of DLC film adhesion. Key Words:Diamondlike carbon, Unbalanced magnetron sputtering, Adhesion, Scratch test, 180 degree bend test