Application oriented tribotesting of thin layers

The general structure and operating variables of tribosystems are presented. The vast set of machine elements are classified as a function of load (or pressure), velocity, type of motion and type of contact. The amelioration of friction and wear properties of the contacting bodies are obtained by lubrication, every time if possible, and by surface modification. For most machine elements the admissible wear for the entire life is low, which makes possible the use of protective thin layers. Besides the determination of mechanical characteristics, for practical applications these layers should also pass a few testing procedures concerning friction and wear comportment: test on simple friction pairs, test on isolated machine parts and tests on parts of the actual machine. For thin layers an important laboratory test is also the fatigue/adhesion test. This will be performed on test devices, which produce a repetitive loading of the surface. For other types of wear a tribometer is used which assures best similarity with the envisaged application concerning type of contact, type of motion, overlap ratio, environment and other relevant parameter of the tribosystem. Because a universal tribometer does not exist one chooses a standardised type or a specially designed tribometer.