The characteristics of anode electrophoresis are: the price of raw materials is cheap (generally 50% cheaper than cathode electrophoresis); The equipment is simple and the investment is less (generally 30% cheaper than cathodic electrophoresis); Lower technical requirements; The corrosion resistance of the coating is worse than that of cathodic electrophoresis (about a quarter of the life of cathodic electrophoresis).
The reasons for the high corrosion resistance of the cathodic electrophoretic coating are: the workpiece is a cathode, no anodic dissolution occurs, and the surface of the workpiece and the phosphating film are not damaged; Electrophoretic coatings (usually nitrogenous resins) have a protective effect on metals, and the paint used is of high price and high quality.
Raw materials are 50% cheaper to use than cathodic electrophoresis
Equipment investment is 30% cheaper than cathodic electrophoresis
Oil removal: The solution is generally a hot alkaline chemical oil removal solution, the temperature is 60 ° C (steam heating), and the time is about 20 minutes.
Hot water washing: temperature 60℃ (steam heating), time 2 minutes.
Rust removal: with H2SO4 or HCl, such as with hydrochloric acid rust removal solution, HCl total acidity ≥ 43 points; Free acidity >41 points; Add 1.5% cleaning agent; Wash at room temperature for 10 to 20 minutes.
Cold water wash: flow in cold water for 1 minute.
Phosphating: with medium temperature phosphating (phosphating for 10 minutes at 60 ° C), the phosphating solution can be commercially available finished products. The above process can also be replaced by sandblasting → washing.
Passivation: with phosphating liquid matching drugs (provided by the manufacturer selling phosphating liquid), 1 to 2 minutes at room temperature. 88% to 91%.
Anode electrophoresis: Electrolyte composition: H08-1 black electrophoretic paint, solid fraction 9% ~ 12%, distilled water mass fraction
Voltage: (70±10) V; Time: 2 ~ 2.5 minutes; Paint temperature: 15 ~ 35℃; Paint PH: 8 ~ 8.5. Note that the workpiece inlet and outlet slot should be powered off. In the process of electrophoresis, the current will gradually decrease with the thickening of the paint film.
Clean water: Wash in running cold water.
Drying: In the oven at (165±5) ℃ temperature 40 ~ 60 minutes can be baked.
hot water washing, degreasing, e.g. degrease pickling - - - and - watch - phosphating wash - - water - electrophoresis - UF1 - UF2 - pure water, pure water washing -- -- -- -- -- -- drop solidified under natural cooling - -, if there is the need for additional surface coating