Microstructure Design of Innovative Interfaces in CVD Hard Coatings - MiDICoat

Project summary

In this project, chemical vapour deposited (CVD) Ti(C,N)/Al2O3 coatings with new interface architecture are developed. Protective coatings based on the Ti(C,N)/Al2O3 stack are currently used in high-speed turning applications. They combine a high wear resistance of the titanium carbonitride with the excellent high-temperature oxidation resistance of aluminium oxide. However, the CVD Ti(C,N)/Al2O3 coatings are still suffering from an insufficient adhesion at the Ti(C,N)/Al2O3 interface and from the formation of voids between the Al2O3 grains. The aim of the project is to improve the interface cohesion via interface design that includes tailoring of the phase composition and morphology of the interfaces, modification of the grain size and adjustment of the ideal preferred orientation of crystallites. Our approach is based on specific alloying of the main components that will improve the heteropitaxy between adjacent phases, stabilize metastable phases and produce desired lattice strains.