Microhardness and elastic modulus of thin coatings applied via PVD and CVD techniques

Abstract

This study investigates the microhardness and mechanical properties of thin coatings applied to cemented carbide cutting tools. Two primary coating techniques were examined: Physical Vapor Deposition (PVD) and Moderate Temperature Chemical Vapor Deposition (MT-CVD). PVD coatings of titanium carbonitride (TiCN) and aluminium titanium nitride (AlTiN) were applied, along with multi-layer CVD coatings consisting of TiCN, titanium carbide (TiC), and aluminium oxide (Al ₂ O₃ ). Depth-sensing indentation (DSI) tests using a Vickers indenter were conducted to determine the microhardness and elastic modulus of the coatings. The Oliver and Pharr method, was employed to analyse load-unload curves, enabling precise evaluation without direct measurement of imprint areas. The results demonstrated that TiCN coatings applied via PVD exhibited the highest microhardness as a complex is 2857 HVIT and elastic modulus among all tested samples is 649 GPa. This superior performance indicates enhanced wear resistance and mechanical stability, which are critical for extending the lifespan and efficiency of cutting tools. While multi-layer CVD coatings also offered benefits, their overall performance was inferior to that of TiCN PVD coatings.