High Temperature Oxidation Behavior of Cr–Al–Si–N Nanocomposite Films Deposited by Filtered Arc Ion Plating Technique

Abstract

High temperature oxidation behavior of nanocomposite films is very important characteristics for application of machining and cutting tools. Quaternary Cr–Al–Si–N nanocomposite films with various compositions were deposited onto WC-Co and Si wafer substrates using a filtered arc ion plating technique. The composition of the films were controlled by different combinations of CrAl2 and Cr4Si composite target power in a reactive gas mixture of high purity Ar and N2 during depositions. The instrumental analyses revealed that the synthesized Cr–Al–Si–N films with Si content of 2.78 at.% were nanocomposites consisting of nano-sized crystallites (3–7 nm in dia.) and a thin layer of amorphous Si3N4 phases. The nanohardness of the Cr–Al–Si–N films exhibited the maximum values of ~42 GPa at a Si content of ~2.78 at.% due to the microstructural change to nanocomposite as well as solid-solution hardening. The Cr–Al–Si–N film shows superior result of oxidation resistance at 1050 °C for 30 min in air. Based on the XRD and GDOES analyses on the oxidized films, it could be revealed that the enrichment of Al (17.94 at.%) and Cr (26.24 at.%) elements in the film leads to form an Al2O3 and Cr2O3 layer on the Cr–Al–Si–N film surface. Therefore, in this study, the microstructural changes on the mechanical properties and oxidation behavior with various compositions in the Cr–Al–Si–N nanocomposite films were discussed and correlated with the deposition parameters.