The single-layer coating TiN prepared by multi-arc ion plating has a face-centered cubic structure and is golden yellow. It is currently the most commonly used coating for cutting tools. The coating equipment has many advantages, such as high hardness, high adhesive strength, low friction coefficient, good corrosion resistance and so on. However, the TiN coating has a low anti-oxidation temperature. When the application temperature reaches 500°C, the coating is significantly oxidized and ablated. Multi-arc ion plating is the main method of TiN coating for physical vapor deposition because of its advantages of high deposition rate and good bonding strength.
In the experiment, a multi-arc ion plating coating process was used to prepare TiN-coated high-speed steel drills and TiN-coated carbide cutters, and a comparative test was performed with TiN-coated and uncoated cutters. The results show that the service life of TiN-coated high-speed steel drills is 5-7 times longer than that of uncoated drills, and the service life of TiN-coated carbide cutters is 3-11 times that of uncoated cutters.
As the most promising substitute material for TiN hard films, TiAlN coatings have higher hardness, higher temperature oxidation resistance, thermal fatigue properties, corrosion resistance, film-based bond strength, and lower surface roughness than TiN. The service life of the TiAlN coated tool is 3~4 times higher than that of the TiN coated tool. The main performance of the TiAlN coating and the TiN coating is shown in Table 1. When TiAlN coated cutters cut high alloy steels, stainless steels, titanium alloys and Ni-base high temperature alloys, they have 3~4 times longer service life than TiN-coated tools. In addition, when the Al concentration in the TiAlN coating is high, the thin amorphous protective film of amorphous Al2O3 is formed on the surface during cutting, which can be more effectively used for high-speed cutting.
Table 1 the main performance comparison of TiAlN coating and TiN coating
Fine columnar face centered cubic structure
Face centered cubic structure