TIN and TiSiN Coated Al2O3/TiCN Ceramic Cutting Tools and Their Cutting Performance

The TiN, TiSiN coatings were deposited on Al2O3/TiCN matrix by physical vapor deposition (PVD) technique. The microstructure, hardness and adhesion evaluation of the coatings were studied by scanning electron microcope (SEM), micro-hardness tester and scratch test, respectively. Turning tests were carried out on both uncoated and coated tool in gray cast iron turning under dry environment. Cutting performance, wear mechanism and machining quality of the uncoated and coated matrix were investigated. The results show that PVD-TiN and TiSiN coating can distinctly improve the hardness of cutting tool by 25% and 65%, respectively, leading to the tool life being enhanced. The dominant wear mechanism of TiN and TiSiN coated tools after turning tests were abrasion, meanwhile TiN coated tool was accompanied by adhesive wear. Compared with the un-coated tools, the PVD coated tools showed no chipping and significant improvement in surface roughness of the finish parts.