pvd coating machine in the coating of why to use high-purity gas, in the vacuum coating industry more in-depth understanding of professionals, may be more aware of the vacuum coating machine is in the vacuum chamber coating, but also must use high-purity gas, so as to ensure that the plated product is benign products.

 In vacuum ion coating, the selection of different gases produced by the liquid gas color will not be the same, argon is generally used to create the coating environment titanium and chromium plating, industrial gas filled with nitrogen can produce silver and yellow products and want to produce black or gray products, you need to add acetylene gas to add oxygen to produce blue products. In addition to gas, the color of the product produced is also affected by conditions such as pressure, temperature, and time.
Under the condition of high vacuum, the high-purity coated metal (such as aluminum) will freely fly apart after evaporation at high temperature and settle on the surface of the workpiece to form a coating. Argon is a protective gas to prevent oxidation reaction from affecting the quality of the coating.
Argon does not participate in the reaction, but increases the air pressure to improve the discharge conditions of the target when coating, argon is not used for coating, mainly used to create a coating environment. Nitrogen and argon are inert gases, after rushing in, one can exclude oxygen, prevent oxidation, two more nitrogen and argon in the diffusion pump content ratio is different, can be coated with different colors. Mainly in order to change the color of the coated product.
If it is said that the gas used in order to adjust the pressure during coating, the personal opinion is as follows: If argon is only a section pressure, the primary pressure is negligible, but the secondary pressure is less than 0.5 atmospheres. Nitrogen is also, mainly because if it is large, it will cause the pressure change in the vacuum chamber to be too drastic, resulting in errors. If the ion source is used, then the argon gas intake should not be too large, which leads to excessive ion amount and burns out parts. The pressure is no different than up there.
Any solid material will dissolve and adsorb some gases in the atmospheric environment, and when the material is placed in a vacuum state, it will exhale because of desorption and analysis. The rate of outgassing is proportional to the amount of gas in the material. The gas composition of different materials and the temperature and time of analysis are different.
The pumping rate of various pumps for different components of gas is also different. When vacuuming, the atmosphere in the container is first removed (this part of the gas is quickly removed, and the gas in the furnace is basically drained at 10-1Pa), and then the gas desorbed on the surface of the material, the gas diffused from the inside of the material to the surface, and the gas permeated into the vacuum through the wall. Therefore, after the goods enter the furnace, they must be kept warm and degassed, because the goods will adsorb some impurity gases before entering the furnace, and we must make these gases parse and desorbed the surface of the goods by proper heating. Taking stainless steel as an example, in addition to the gas adsorbed on its surface, some gases will be precipitated inside the steel during the continuous heating and insulation process, and the existence of these gases often has a greater impact on the purity and color of the film, and also has a great impact on the adhesion of the film layer.
Therefore, when the pvd coating machine is coated, the quality of the film, the gas plays a key role, and it is an indispensable step in the coating process.