Microstructure and Mechanical Properties of κ-Al2O3/TiCN Coating Prepared by CVD

Abstract

The κ-Al2O3/TiCN multilayer coatings have been deposited on cemented carbide cutting tools using chemical vapor deposition (CVD). The morphology of the surface and cross-section were examined by scanning electron microscope (SEM). The adhesion force and scratch resistance of κ-Al2O3/TiCN coating were determined by CSM scratch tester. The results showed that the etching reagents and etching times had an evident influence on the morphology of the cross-section of κ-Al2O3/TiCN coating. The surface of κ-Al2O3/TiCN coating exhibited hexagon grain structure. The κ-Al2O3 layer showed columnar structure while the TiCN layer exhibited fibrous structure with long-needle grains. The results of scratch testing indicated that the -Al2O3/TiCN coating failed at coating/substrate and layer/layer interface by delaminating rather than by cracking or chipping due to long needle-like and columnar structure.