Microstructure and Wear of Cathodic Arc Physical Vapour Deposited on TiAlN, TiCrN and n TiAlN Alpha Si3N4 Films

Present study examined the microstructural features, hardness and wear performance of TiAlN, TiCrN and n-TiAlN/α-Si3N4 coatings deposited by cathodic arc physical vapour deposition (CA-PVD) technique on M-50 steel keeping in mind a possible application of hybrid bearings in next generation aero-engine. Microstructural features of the coatings were evaluated using scanning electron microscopy (SEM) and transmission electron microscopy. Hardness was measured using microhardness tester. Wear test was carried out with the help of ‘Bruker’ tribometer. Worn surfaces were characterised employing SEM. Results show that TiCrN coating has crystalline columnar structure and other coatings have nano-crystalline structures. Besides improved hardness, TiAlN has best wear resistance and TiCrN coating exhibits least friction coefficient.