Paper SE-TuA12
Thick CrN/AlN Superlattice Coatings for Solid Particle Erosion and High Temperature Wear Resistant Applications

Tuesday, October 23, 2018, 6:00 pm, Room 202C

Energetic ion bombardment is critical to improve the structure and properties of coatings in plasma assisted depositions. Plasma enhanced magnetron sputtering (PEMS) is an advanced version of conventional magnetron sputtering by generating a global plasma, in addition to the magnetron plasma, in the entire deposition system using hot filament thermionic emission to enhance the ionization and bombardment. In this study, thick CrN/AlN superlattice coatings (15 to 20 μm) were deposited by reactive sputtering using a combination of PEMS and high power impulse magnetron sputtering (HiPIMS) techniques. These coatings were deposited at different PEMS plasma discharge currents (0 to 4 A) which represent different ion fluxes for the bombardment. The bilayer thickness of the nanolayers was controlled in the range of 4 to 7 nm. The microstructure of the coatings gradually changes from long columnar grains to extremely dense structure with an increase in the PEMS discharge current. These coatings exhibited high hardness, excellent adhesion, and excellent resistance to high temperature wear, oxidation and solid particle erosion. The high temperature wear resistance of selected coatings was measured using a high temperature pin-on-disc tribometer in the ambient air from 600 °C to 1000 °C. The solid particle erosion resistance of these thick CrN/AlN coating was evaluated and compared with other thick hard coatings, e.g. CrN, TiN, TiSiCN, etc., using an air jet sand erosion tester. In this presentation, PEMS/HiPIMS deposition process, the coating microstructures, erosion, and high temperature wear test results will be discussed.