Diesel-lubricated ta-C coatings

Samples coated with tetrahedral amorphous carbon were investigated in two different oscillating test setups regarding their friction and wear properties. As lubricants petrodiesel, rapeseed methyl ester biodiesel and a mixture thereof were used. Compared with a petrodiesel-lubricated uncoated system, friction was reduced for more than 50% when a tetrahedral amorphous carbon coating was applied and biodiesel added to the lubricant. Impurities of monoglycerides are assumed to be the cause for the friction-modifying effect.