Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : September 11, 2022 - September 14, 2022
In recent years, the demand for lubrication in the atmosphere has been increasing, and carbon-based hard coatings Diamond-like Carbon (DLC) have been attracted attention. A tetrahedral type of DLC with tantalum (ta-C:Ta) has been exhibited ultra-low friction approximately 0.07 in the atmosphere. The friction coefficient is thought to decrease due to an increase in the graphite structure at the topmost surface which was formed by desorption of oxygen from carbon or tantalum and restructuring of carbon structure. Which is assumed to be driven by energy from the application of frictional heat or shearing. If the oxygen desorption phenomenon described above can be realized by applying energy other than friction, low friction can be obtained without friction beforehand. It has been reported that irradiating CNx coatings with ultraviolet light desorbs nitrogen atoms from the surface of the CNx coating, reducing the initial friction period by 91 %.
In this study, we clarified the effect of UV irradiation on the oxygen desorption in the ta-C:Ta0.024 coating (Ta content was 0.024) . AES and XPS revealed that UV irradiation caused C-O bond cleavage and oxygen desorption.
