Investigation of the Tribological Behaviour of Advanced TiAlN and CrAlN Hard Coatings Deposited on X153CrMoV12 Cold Work Tool Steel

Due to the recent developments and growth in the field of surface engineering, several new coatings and deposition techniques, such as PVD, CVD, and PACVD (Plasma Assisted Chemical Vapour Deposition) are increasingly applied in the industry. Duplex technologies, like the combined processes involving a PVD or PACVD coating and a preliminary plasma nitriding, enhance the mechanical, chemical, and physical performance of the surface layer in a new, efficient way. The objective of our research work is to investigate the tribological behaviour of two, industrially applied duplex treated advanced TiAlN and CrAlN hard coatings, which can efficiently be used to improve the lifetime of the X153CrMoV12 cold work tool steel. Instrumented scratch tests with constant and progressive loading were carried out to compare the resistance of the two hard coatings to scratching, while ball-on disc tests were accomplished to compare their wear resistance. The investigations were supplemented with morphological analysis of the scratch grooves and wear tracks using optical microscopy, while the coatings were characterised with their microVickers hardness and layer thickness determined by the ball cratering method. Results prove a significant improvement of the tribological performance of the tested coatings compared to the uncoated reference material and superior wear behaviour of the CrAlN coating in terms of both scratch and wear resistance.