Vacuum Furnace Gas Deposition
Gas deposition technology:
Vapor deposition is the formation of functional or decorative metal, non-metal or compound coatings on the surface of workpiece by utilizing the physical and chemical processes occurring in the gas phase. According to the film forming mechanism, vapor deposition technology can be divided into chemical vapor deposition, physical vapor deposition and plasma vapor deposition.
At present, physical or chemical vapor deposition method can be used to prepare tungsten coatings, or vapor deposition method can be combined with other preparation techniques to improve the performance of tungsten coatings.
Chemical vapor deposition
Place the workpiece in the reaction chamber, vacuum and heat it to 900 ~ 1100 C. If TiC layer is to be coated, titanium is introduced into the reaction chamber with volatile chlorides (such as TiCl4) and gaseous hydrocarbons (such as CH4). At this time, TiC will be formed by chemical reaction on the surface of the work piece and deposited on the surface of the work piece to form a 6-8 micron thick coating. After vapor deposition and plating, the workpiece is quenched and tempered. The surface hardness can reach 2000~4000HV.
Physical vapor deposition
Physical vapor deposition (PVD) is a process of evaporation, ionization or sputtering, which produces metal particles and reacts with reactive gases to form compounds deposited on the surface of the workpiece. Physical meteorological deposition methods include vacuum plating, vacuum sputtering and ion plating. At present, ion plating is widely used.
Ion plating is to vaporize and evaporate the plating material (e.g. titanium) by means of glow discharge of inert gas. Ions are accelerated by electric field to bombard the workpiece surface with higher energy. At this time, TiC and TiN coatings can be obtained on the workpiece surface if reacting gases such as CO2 and N2 are introduced. The hardness of TiC and TiN coatings is up to 2000 HV. The important characteristic of ion plating is that the depositing temperature is only about 500 C, and the coating has strong adhesion. It is suitable for high-speed steel tools, hot forging dies and so on.