Tribological Study of a Tetrahedral Diamond-Like Carbon Coating under Vegetable Oil–Based Lubricated Condition

Abstract

Maintaining a clean environment is the major concern of industries that produce fuel and lubricants for automotive applications. Thus, vegetable-based oils are being explored for the preparation of biobased lubricants because of their biodegradability and nontoxicity. Despite their low thermal stability, vegetable oils show better tribological characteristics than mineral oils. Nonetheless, the thermal stability of vegetable oils could be improved by transesterification. In this study, three vegetable-based oils (sunflower, palm, and coconut) were used to investigate the tribological properties of ta-C diamond-like carbon (DLC) coating under DLC–steel contact condition. A BICERI ball-on-a plate tribotesting machine was used to conduct experiments. During the experiment, test contacts of tribopairs lubricated with sunflower oil exhibited better tribological characteristics than those using coconut oil as a lubricant.

KEY WORDS:

• COF
• Wear Rate
• Graphitization
• Transfer Layer
• Vegetable Oil

Funding

I am grateful to the University of Malaya. This project was supported by the University of Malaya Research Grant CG060-2013.