The corrosion products generated by the aluminum alloy die castings due to the action of the medium form a layer of film, which closely covers the surface of the aluminum alloy die castings, and changed the surface state of the aluminum alloy die castings, the electrode potential of the aluminum alloy die-casting part is greatly changed in the positive direction, and becomes a passive state of corrosion resistance.
After the passivation treatment, it has the characteristics of not increasing the thickness of the parts and changing the colour, which improves the precision and added value of the product and makes the operation more convenient;
Since the passivation process is carried out in a non-reactive state. The passivation agent can be added and used repeatedly, so life is the cost is more economical.
Passivation promotes the oxygen molecular structure passivation film formed on the surface of aluminum alloy die castings, the film layer is dense, the performance is stable, and it has a self-repairing effect in the air at the same time. Therefore, compared with the traditional anti-rust oil method, passivation The passivation film formed by chemical treatment is more stable and corrosion-resistant.
The first process: pre-degreasing - main decreasing - water rinsing - water rinsing - whitening and descaling - ultrasonic cleaning -water rinsing - activation - water rinsing - water rinsing - passivation - water rinsing - water rinsing - drying. That is a relatively complete process, which is widely suitable for different passivation environments and aluminum alloy products.
The second process: degreasing-water rinsing - water rinsing - activation - water rinsing - water rinsing - passivation - water rinsing - water rinsing - drying. That is the process flow after aluminum alloy polishing.
The third process: degreasing-water rinsing - water rinsing - passivation - water rinsing - water rinsing - drying. If the casting part is mechanically polished, the film colour is required to be natural, and the corrosion resistance is not high. For example, the neutral salt spray test requires about 48-72 hours, can try this simplified process.
The fourth process: degreasing-water rinsing - passivation - water rinsing - drying. If the casting parts drain well and the part structure is relatively simple, then you can choose to streamline the process flow.