Thermal analysis of friction in coated elastohydrodynamic circular contacts

• Low thermal inertia coatings reduce friction in TEHD contacts.
• High thermal inertia coatings increase friction in TEHD contacts.
• Friction variations are attributed to thermal effects within the lubricated contact.
• Friction variations are more pronounced when both contacting surfaces are coated.
• Friction is more affected when the faster moving surface is coated.

This paper presents a thermal analysis of friction in coated elastohydrodynamic contacts. In a previous work by the author, it was found that friction may be controlled in elastohydrodynamic contacts by a suitable choice of surface coatings based on thermal properties. Low thermal inertia coatings would reduce friction while high thermal inertia coatings would increase it. The current work attempts to investigate the origins of these observations by running a comprehensive thermal analysis of these contacts. It is also found that when both contacting surfaces are coated, friction is more influenced than when only one is coated and in the latter case, under rolling–sliding conditions, friction is more affected when the faster moving surface is the coated one.