Caracterização mecânica dos revestimentos AlTiN/TiSiN, TiCN e AlCrN depositados por processo PVD

Abstract

With the development of industry and the application of difficult-to-machine materials, combined with machining processes that employ increasingly higher speeds, studies seeking to increase cutting tool life and improve their mechanical performance have become ever more necessary. Therefore, the present work presents the mechanical and tribological characterization of AlTiN/TiSiN, AlCrN, and TiCN coatings deposited via cathodic arc PVD onto ISO S10 grade cemented carbide (WC-Co) substrates. The methodology involved surface characterization using confocal microscopy to determine roughness, and scanning electron microscopy (SEM) for thickness measurement and morphological analysis. Adhesion was evaluated through progressive-load scratch testing, and interface integrity was assessed by Rockwell C indentation based on the VDI 3198 standard. The tribological behavior was analyzed using reciprocal pin-on-plate testing (ASTM G133) with an alumina counter-body, monitoring the coefficient of friction (CoF) and wear mechanisms via SEM and energy-dispersive X-ray spectroscopy (EDS). The results demonstrated that the AlTiN/TiSiN coating exhibited the lowest roughness and the highest critical failure load (15 N), indicating superior adhesion and a potential advantage regarding chip flow over the coated surface. In the Rockwell C test, although AlCrN showed better initial performance under a 588 N load, all systems exhibited severe failure under a 1471 N load. The pin-on-plate tests indicated that the aluminum-based coatings promote the formation of protective tribofilms (Al2O3 and Cr2O3), which stabilize the CoF. EDS analyses revealed that the AlCrN coating maintained its integrity after 100 m of sliding, whereas the AlTiN/TiSiN coating allowed exposure of the substrate.