Abstract
This study was carried out to provide the diamond film with enhanced adhesion to the cemented carbide substrate by changing coating conditions in EACVD.
Result of a series of experiments reveals that the adhesion of coating to the substrate is mainly related to the pre-treatment of the substrate surface, methane gas concentration and the substrate temperature during deposition.
Pre-treatment by lapping the substrate surface with diamond powder was effective to enhance the adhesion, which imply the lapping promotes nucleation sites of diamond deposition.
The appropriate methane content was 1-1.5%, and the substrate temperature for the best coating was 800-950°C to provide the well adhered coating on the substrate. In addition, the diamond film deposited by above condition was confirmed to consist of pure diamond crystals and adhesion of the film was far better than that of the film consisting of diamond crystals including considerable amount of amorphous carbon.
Performance of the diamond coated tool was tested by dry cutting of an aluminum alloy containing 8%Si. The diamond coated tool was confirmed to last for long time in continuous turning.
