Tribometers are used to examine the friction behaviour of material pairs. A counter body such as a steel ball is applied to a rotating specimen with a defined normal force (approximately 5 N) (pin-on-disc). The friction coefficient is calculated from the frictional force and normal force. Tribological investigations are used to determine low-friction and wear-resistant material pairs for technical movement systems.

Fraunhofer IST has special high-temperature tribometers for test temperatures up to 1000 °C and high-load tribometers with normal forces in the range of 10 to 1000 N. Studies using fluid lubricants are possible as well.

Pin-on-disc friction MeCH

Pin-on-disc friction and wear testing MeCH
© Fraunhofer IST

Metallic DLC layers exhibit significantly lower friction resistance against steel compared to uncoated surfaces. Metal-DLC layers also improve the friction coefficient compared to steel against steel during operation under oil.

Pin-on-disc compared to dry running against steel

 Tribometer TiN layer
© Fraunhofer IST

A TiN layer is generally harder than a DLC layer and therefore offers good protection against wear compared to uncoated steel. But with moving components, a DLC layer exhibits a friction coefficient that is multiple times smaller than TiN or uncoated steel, especially during non-lubricated operation.