91 / 2021-07-01 10:09:16

Influence of Mo Content on the AlCrSiN/Mo Self-lubricating Coatings Prepared by Hybrid Magnetron Sputtering

AlCrSiN/Mo self-lubricating coating, Mo content, Hybrid magnetron sputtering, Microstructure, Friction and wear

AlCrSiN coatings with exceptional oxidation resistance and remarkable mechanical properties are often used as promising protective layers on cutting tool surface. Due to the inferior frictional properties at elevated temperatures, AlCrSiN coatings are unable to meet the machining requirements at higher cutting speed. The addition of Mo element is an effective method to reduce friction because MoO₃ lubricating phase could be generated during the friction contact. In this work, the AlCrSiN/Mo self-lubricating coatings with different Mo contents were deposited by high power impulse magnetron sputtering and pulsed DC magnetron sputtering hybrid technique. The influence of Mo content on the microstructure and properties of the AlCrSiN/Mo coatings were investigated. The resulted coatings were characterized and tested by SEM, EDS, XRD, scratch tester, nano-indenter, and high temperature tribometer. The results showed that AlCrSiN coating was mainly composed of fcc-(Cr, Al)N phase, and had dense microstructure and high nano-hardness of about 20.1GPa. But the coating presented the highest friction coefficient of 0.649, and the highest wear rate of 2.09×10^-2 μm²/N. When the Mo content was 21.4 at.%, the AlCrSiN/Mo coating presented the best comprehensive properties, namely the nano-hardness, critical load, friction coefficient, and wear rate reached 17.54 GPa, 68 N, 0.54, and 7.97×10^-4μm²/N, respectively. In this case, the characteristic value H/E and H³/E^*2 were also the maximum.