Effect of silicon contents on mechanical properties and tribological behavior of (AlCrNbTiMoSix)N multicomponent nitride coatings fabricated by radio-frequency magnetron co-sputtering

This research involved the fabrication of nitride coatings (AlCrNbTiMoSix)N with varying silicon contents using RF magnetron co -sputtering. The hardness of these coatings increased from 28.5 to 33.5 GPa, primarily because of several strengthening mechanisms. These mechanisms encompassed refining the grain size, inducing high residual stress through point defects resulting from the peening effect in the sputtering process. Additionally, Si3N4 precipitated within the grain boundaries through spinodal decomposition, giving rise to a nanocomposite structure referred to as nc-(AlCrNbTiMo)N/a-Si3N4. The presence of Si3N4 within grain boundaries inhibited dislocation movement and grain boundary sliding, consequently enhancing the cohesive strength of both the grains and phase boundaries. During tribological testing at room temperature, coatings with silicon contents of 0, 3.3, and 4.9 (at. %) displayed low wear rates of 0.85, 2.27, and 3.28 x 10 - 6 mm3N-1 m-1, respectively. The low friction coefficients of coatings can be attributed to the formation of a self-lubricating layer. Furthermore, the coating without silicon addition characterizes the lowest wear rate, which is attributed to the high residual stress that inhabit crack propagation, and low Young's modulus allows for the dispersion of external loads across a broader elastic strained region, thereby contributing to the optimal wear resistance. This study demonstrates that (AlCrNbTiMoSix)N coatings have the potential to serve as promising materials for anti -wear applications due to their favorable mechanical and lubricating properties.