The Characteristics and Thermal Stability of CrN/AlSiN Multilayer Coatings
CrN/AlSiN multilayer coatings with bilayer period (Λ) between 2.3 nm and 8.0 nm were synthesized from Cr and AlSi (Si=20 and 66 at.%) targets by using a closed-field unbalanced magnetron sputtering (CFUBMS) and their crystal structure, chemical composition and mechanical properties have been investigated by glow discharge optical emission spectroscopy (GDOES), Xray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS) and nano-indenter. In order to evaluate the thermal stability of the coatings annealing treatments for 30 min at temperature between 800 °C and 1000 °C were performed in air. The thermal stability of the CrN/AlSiN multilayer coatings was improved with increasing Si content. In case of the coating with Si content of 18.2 at.%, a superior thermal stability was exhibited even after annealed at 1000 °C and the relatively high hardness of 25 GPa was maintained without a significant decrease in hardness. The reduced oxidation rate of the coatings at high temperature could be attributed to the formation of the amorphous Si3N4 phase around the crystalline AlN phase.
Alan K.T. Lau, J. Lu, Vijay K. Varadan, F.K. Chang, J.P. Tu and P.M. Lam
S.M. Kim et al., "The Characteristics and Thermal Stability of CrN/AlSiN Multilayer Coatings", Advanced Materials Research, Vols. 47-50, pp. 1498-1501, 2008