AlSiTiN nanocomposite coatings developed via Arc Cathodic PVD: evaluation of wear resistance via tribological analysis and high speed machining operations

The aim of this work is the development and characterisation of innovative ceramic coatings for cutting tools with high wear resistance properties at high temperatures. This objective arises from the industrial need of reducing machining time and consumption of lubricants, in order to reduce machining costs, environmental impact and health risks for the operators. The use of coatings for cutting tools is nowadays widespread, however, wear mechanisms are not always understood, and a clear relationship between coating’s laboratory characterisation and operational machining performance are seldom assessed. The possibility of correlating the laboratory characterisation results with real tools operational performances would be a key issue in reducing development costs of innovative coatings. Nanocomposite coatings, consisting of nanocrystalline AlTiN dispersed in an amorphous matrix of Si3N4 were deposited onto hard metal substrates via Cathodic Arc PVD (physical vapour deposition). Coating’s thickness, adhesion and hardness have been evaluated. Wear resistance was determined through tribological tests under different temperatures and the main wear phenomena were studied using SEM-EDS analysis. Coated WC cutting tools were employed in high speed, dry milling on AISI M2 die steel. Cutting performances, laboratory tests results and wear mechanism have been inspected, comparing with other commercial nitride-coated tools.