Improvement of Hardness and Toughness of TiAlN Coating by Nanoscale Multilayered Structurization with Si3N4

Abstract

The Ti(Al)-Si based nitride coating material has been studied due to its excellent mechanical properties such as hardness and oxidation resistance as in the Ti(Al)N/a-Si3N4 nanocomposites with high hardness over 50 GPa. In this study, the effect of microstructure, especially layer thickness of TiAlN and Si3N4 phase, on the mechanical properties of the TiAlN/Si3N4 nanoscale multilayered coating has been investigated. By nanoscale multilayered structurization with a thin Si3N4 layer (similar to 0.3 nm), the hardness and toughness of TiAlN coating were greatly improved. It is known that for the TiAlN/Si3N4 nanoscale multilayered coatings, thickness of the Si3N4 layer is the most important factor and should be carefully controlled to obtain coatings with high hardness and toughness.