HiPIMS nitride coatings for thermal and tribological applications

In this work, two different nitride coating typologies designed to answer to two different technological problems are presented. They are deposited by High Power Impulse Magnetron Sputtering (HiPIMS) technology which permits to produce high performance coatings thanks to an ultra-dense plasma leading to a high ionization degree of the sputtered material. This allows depositing hard nitride coatings also on temperature sensitive substrates, without affecting their mechanical and dimensional properties. Mo-N coatings were grown on commercial AlSi alloy pistons, to increase their resistance to wear in an internal combustion engine. AlTiN-based coatings were deposited on innovative intermetallic TiAl alloy to improve their hot corrosion and wear resistance. The mechanical and tribological properties have been deeply investigated by nanoindentation, friction, wear and scratch tests. Morphology, composition, crystal structure and thickness were analyzed by SEM-EDS, XRD, calotest and optical microscopy.