Improvement of Hardness and Toughness of TiAlN Coatings

by Nanoscale Multilayered Structurization with Amorphous Si-N Phase


J.-K. Park*, C. Ziebert**, M. Stüber** and Y.-J. Baik*


* Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650,
South Korea

** Forschungszentrum Karlsruhe, Institut für Materialforschung I,  Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany



Recently, Ti(-Al)-Si-N nanocomposite coatings were known to have excellent hardness and high temperature stability, compared to the TiAlN coatings. In this study, we have investigated the microstructure, hardness and toughness of TiAlN/a-Si-N nanoscale mulilayered coatings. The TiAlN/a-Si-N nanoscale mulilayered coatings were deposited on M2 HSS and Si wafer by D.C. magnetron sputtering with TiAl alloy and Si targets. N2 and Ar were the reactive gases. Bilayer period of nanomultilayer was controlled by changing rotation speed of substrate holder. For a fixed rotation speed, relative thicknesses of the amorphous Si-N and crystalline TiAlN were also controlled by changing Si and TiAl target power density. The phase, microstructure and hardness of the obtained coatings were measured. Toughness of the TiAlN/a-Si-N was assessed by nanoindentation technique. Changes in hardness and toughness of the coatings after heat-treatment in N2 atmosphere were also investigated. Effect of bilayer period and relative thicknesses of amorphous Si-N and crystalline TiAlN on the hardness and toughness of the TiAlN/a-Si-N nanoscale mulilayered coatings will be discussed.

This research was supported by a grant (code # : M60401000171-05A0100-17110) from International Collaborative R&D Programs of the Ministry of Science and Technology, Korea