The Friction and Wear Properties of CrN, Graphit-iC and Dymon-iC Coatings in Air and under Oil-lubrication.

NITRIDE COATINGS have always been the popularchoice for increasing the wear lifetime for industrialcomponents.TiN is the most widely accepted butrecently CrN has been gaining more interest due itsthermal stability and good performance in corrosiveenvironments.Knowledge of the tribologicalperformance of CrN coatings in dry and lubricatedconditions is still quite limited1,2].Many authorshave studied the properties of diamond like carbon(DLC)films and how they perform in dry conditions…

The Friction and Wear Properties of CrN, Graphit-iC and Dymon-iC Coatings in Air and under Oil-lubrication.

Hard ceramic coatings such as TiN and CrN are very successful and are widely used in improving the performance of cutting and forming tools, but they are less successful in providing protection for general machine components, such as gears and engine parts. The development of low-friction wear resistant coatings that can run dry or in a minimum amount of oil is becoming increasingly important to this industry. Two recently developed carbon-based coatings Graphit-iC? and Dymon-iC, which are shown to exhibit very high sliding wear resistance and low friction in dry conditions, are compared to a CrN coating under oil lubricated conditions. Long term pin-on-disc tests using a chrome steel counterface ball were carried out on coated HSS test samples. All the coatings performed well at very high applied contact pressures, exceeding 1.5 GPa, but the Graphit-iC? and Dymon-iC coatings also exhibited the desirable characteristic of protecting the counterface material. Reasons for this behaviour are discussed.