Corrosion resistance of aluminum and aluminum alloy processed products of pvd coating machine: Aluminum has high chemical activity. At 20 °C, its standard potential is -1.69 V, which is easy to form a firm and dense oxide film with oxygen in the air, raising the standard potential to -0:5V, so aluminum is corrosion-resistant in the atmosphere. The increase of impurities in the vacuum coater can destroy the continuity of the oxide film or form a micro-battery, which will reduce its corrosion resistance. The corrosion resistance of aluminum in pure water mainly depends on the water temperature, water quality and the purity of aluminum. When the water temperature is lower than 50 °C, with the improvement of water quality and aluminum purity, the corrosion resistance of aluminum improves; the corrosion type is mainly pitting corrosion. If the water contains a small amount of active ions (Cu+, Cu-, etc.), the resistance of aluminum decreases sharply.

      The pure aluminum of the pvd coating machine is higher than that of the aluminum-magnesium alloy; this kind of alloy has a tendency to exfoliate and corrode in the cold deformation state, and this tendency increases with the increase of the degree of cold deformation. Vacuum coaters are used to improve the corrosion resistance of hard aluminum in marine and humid atmospheres. It can be artificially protected by covering it with a layer of pure aluminum, and the purity of the aluminum covering should be greater than 99.5%. For thin plates, the thickness of the aluminum cladding layer shall not be less than 4% of the plate thickness on each side.
       In order to improve the corrosion resistance of the plate, the vacuum coating machine can be coated with aluminum on the surface; however, due to the high content of copper in the substrate, it is easy to diffuse copper, so its corrosion resistance is still lower than that of the aluminum-clad plate of 2A12 alloy. The corrosion resistance of 2A16 alloy extrusion cut products is not high, and it has a tendency to stress corrosion when artificially aged at 160 to 170 ° C for 10 to 16 hours; and its weld and transition zone have a high tendency to intergranular corrosion; anodizing and coating Paint protection.
       The gold content of super hard lead in pvd coating machine is higher than that of hard aluminum alloy, but lower than that of aluminum-manganese, aluminum-magnesium, and aluminum-magnesium-silicon alloys. The pvd coating machine has a super-hard aluminum plate with an aluminum layer; its corrosion resistance is greatly improved. Coating equipment For extruded materials and forgings that are not covered with chrome; surface protection can be performed by anodizing or painting. The stress corrosion resistance of super-hard aluminum alloys in vacuum coating equipment is poor in the quenched natural aging state, but its corrosion resistance is increased in the quenched artificial aging state. In recent years, studies have proved that the use of graded aging process can reduce its stress corrosion. Sensitivity.