Friction and wear measurement of material pairings

A pin-on-disk tester in use at the Fraunhofer IST.
© Fraunhofer IST
A pin-on-disk tester in use at the Fraunhofer IST.

The Pin-on-Disk Test (DIN 50324-07, ASTM G99-05, ISO 18535)

Tribometers can be used to investigate the friction and wear behavior of material pairings. A test material, e.g. a steel ball or a pin, is moved on a circular path over the specimen with a defined standard force (approx. 5 N) (pin-on-disk). During the test, the friction force or the coefficient of friction is measured continuously. The wear is subsequently determined by measuring the wear track and the abrasion of the test specimen.

How the test is used

Friction and wear are not material values. Rather, they depend not only on the material pairing but also on the test parameters: 

  • Mode: oscillating or rotating
  • Load: 1 - 10 N
  • Duration: 10 - 100,000 cycles
  • Frequency: 0.5 - 5 Hz
  • Counterbody: steel, carbide, ceramic, special materials
  • If applicable, media (e.g. air, water, oil)

We will be pleased to advise you on the optimum choice of test conditions.

Coefficient of friction of different material pairings

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

DLC coatings containing metal have a significantly reduced frictional resistance to steel compared to uncoated surfaces. Even when operating under oil, metal DLC coatings still improve the coefficient of friction compared to steel against steel.

Friction comparison during dry running against steel

 Tribometer TiN layer
© Fraunhofer IST

A TiN coating is generally harder than a DLC coating and therefore offers good wear protection compared to uncoated steel. In moving components, however, a DLC coating offers a coefficient of friction that is many times lower than that of TiN or uncoated steel, especially when running without lubrication.

Our focus and expertise

 

Expertise

Tribology