Modern material processing technologies are moving towards increasingly challenging cutting conditions. These conditions require cutting tools to be covered with effective protective coatings. Such coatings must withstand high thermomechanical loads and be persistent against degradation in demanding environments.
For this purpose, protective coatings based on transitional metal nitrides have been used for many years, as they offer high protection of the tool against high loads such as elevated temperature and pressure. Before being used in production, each process of developing new coatings must also include tribological tests at temperatures that are relevant for daily application of the coating. Wear represents progressive damage to the contact surface, which also involves loss of coat material. It occurs on surfaces that are exposed to stresses (forces) and, at the same time, the relative movement between them.
In my master's thesis, I measured the coefficient of friction on a high temperature tribometer which was used to calculate the wear for the AlTiN coating at higher temperatures. The tribological characterization of coatings consists of a set of tribological tests of different lengths at different temperatures. This was how I was able to determine when during the tribological test maximum wear occurred and how friction and wear changed from initial contact to the failure of the coating.
After each tribological test, I measured the wear route using a profilometer and determined the wear. I also analyzed individual samples using a line electron microscope and EDS-analysis. I was interested in the effect of temperature on the tribological properties of the AlTiN coating. In the first part of the assignment, the theoretical foundations are presented, followed by the experimental part, and the description and interpretation of the results.
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