1. Thermal CVD technology
Hard coatings are mostly metal ceramic coatings (TiN, etc.), which are formed by the reaction of metal in the coating and reactive gasification. At first, the thermal CVD technology was used to provide the activation energy of combination reaction by thermal energy at a high temperature of 1000 ℃. This temperature is only suitable for depositing TiN and other hard coatings on cemented carbide tools. So far, it is still an important technology to deposit TiN-Al20 composite coatings on cemented carbide tool heads.
2. Hollow cathode ion coating and hot wire arc ion coating
In the 1980s, hollow cathode ion coating and hot wire arc ion coating were used to deposit coated cutting tools. Both of these ion coating technologies are arc discharge ion coating technologies, with a metal ionization rate of up to 20%~40%.
3. Cathode arc ion coating
The emergence of cathodic arc ion coating has led to the development of the technology of depositing hard coatings on molds. The ionization rate of cathodic arc ion coating is 60%~90%, allowing a large number of metal ions and reaction gas ions to reach the surface of the workpiece and still maintain high activity, resulting in reaction deposition and formation of hard coatings such as TiN. At present, cathodic arc ion coating technology is mainly used to deposit hard coatings on molds.
The cathode arc source is a solid-state evaporation source without a fixed molten pool, and the arc source position can be arbitrarily placed, improving the space utilization rate of the coating room and increasing the furnace loading capacity. The shapes of cathode arc sources include small circular cathode arc sources, columnar arc sources, and rectangular flat large arc sources. Different components of small arc sources, columnar arc sources, and large arc sources can be arranged separately to deposit multi-layer films and nano multilayer films. Meanwhile, due to the high metal ionization rate of cathodic arc ion coating, metal ions can absorb more reaction gases, resulting in a wide process range and simple operation to obtain excellent hard coatings. However, there are coarse droplets in the microstructure of the coating layer obtained by cathodic arc ion coating. In recent years, many new technologies have emerged to refine the structure of the film layer, which has improved the quality of the arc ion coating film.
——This article was released by Guangdong Zhenhua Technology, a manufacturer of optical coating machines.
Post time: Apr-28-2023