There are three conventional methods for surface treatment of aluminum profiles: electrophoresis, spray coating, and fluorocarbon (一)
Electrophoresis: Electrophoresis is the application of electrophoretic paint on the yin and yang poles. When the voltage is applied, the charged paint ions move to the cathode and form an insoluble matter with the alkaline action generated on the surface of the cathode, which is deposited on the workpiece surface.
Advantages and disadvantages of electrophoretic surface treatment process:
The electrophoretic paint film has the advantages of fullness, uniformity, flatness and smoothness. The hardness, adhesion, corrosion resistance, impact performance and permeability of the electrophoretic paint film are significantly better than other coating processes.
The biggest drawback is that the color of electrophoresis is relatively single, with only a few colors (silver white, champagne, golden, black, imitation stainless steel). Secondly, electrophoretic colors are susceptible to color differences.
Now introduce the electrostatic powder coating
(二) powder coating:
Use electrostatic dusting equipment to spray powder coating on the surface of the workpiece. Under the action of static electricity, the powder will be evenly adsorbed on the surface of the workpiece to form a powder coating.The spraying effect is superior to the spray painting process in terms of mechanical strength, adhesion, corrosion resistance and aging resistance.
Advantages and disadvantages of electrostatic powder coating
Advantages of powder coating are:
(1) High efficiency and energy saving: Because it is a one-time film formation, it can increase productivity by 30-40% and reduce energy consumption by about 30%.
(2) Less pollution: no organic solvent volatilization (excluding toluene, xylene and other harmful gases in paints and coatings)
(3) The coating film performance is good: the thickness of one-time film formation can reach 50-80μm, and its comprehensive indicators such as adhesion and corrosion resistance are relatively excellent.
(4) Various colors, various colors can be made according to customer requirements, and produce chromatic aberration.
(1) relatively bright colors are easy to fade
(2) The surface of the profile with poor surface treatment is easy to produce orange peel and even powder.
(三) fluorocarbon spraying:
Pre-treatment process: degreasing and decontamination of aluminum material → water washing → alkaline washing (defatting) → water washing → pickling → water washing → chromizing → water washing → pure water washing
Spraying process: spray primer → top coat → overcoat paint → baking (180-250 ℃) → quality inspection
The multi-layer spraying process uses three sprays (referred to as three sprays), sprays a primer, a top coat and a finishing paint and a secondary spray (primer, top paint).
Advantages and disadvantages of fluorocarbon spraying
(1) Weather resistance — anti-ultraviolet degradation, strong resistance to chalking, long-term maintain color and gloss.
(2) Chemical resistance—with resistance to acid and liquid alkali, and free from air pollution and acid rain.
(3) Corrosion resistance — low permeability of corrosive particles in the air, it can withstand long-term harsh environment without corrosion.
(4) Mechanical properties-with excellent impact resistance, abrasion resistance and excellent film flexibility.
(1) High price
(2) If it is not handled well, it is easy to produce orange peel.