Electrolytic coloring of aluminum alloy has good decoration, so it has been widely applied at home and abroad, especially in the surface treatment of building aluminum profile.
The main process is the use of Sn Ni mixed salt electrolytic coloring, produce the product color to champagne, compared with single nickel salt coloring, tin nickel mixed salt electrolytic coloring products of bright colors, full color; the main problem is the product difference, extrusion process and oxidation coloring process for aluminum production process the unreasonable will lead to product color.
The influence of extrusion process on the oxidation and coloring of aluminum alloy is mainly affected by die design, 5052 aluminum extrusion temperature, extrusion speed and cooling way on the surface state and uniformity of extruded profiles. The mold design should make full feed blend, or prone to bright (dark) with defects, may appear color one profile; at the same time, the state and the surface profile extrusion mold lines also affect oxidation coloring. The extrusion temperature, speed, cooling mode and cooling time are different, so that the profile of the profile is not uniform and the color difference will be produced.
Have a very important influence on electrolytic coloring of anodic oxidation of aluminum alloy color, especially in the production line of vertical oxidation process is prone to two color, vertical oxidization groove depth 7.5m, upper and lower tank is easy to produce temperature difference, the temperature has great influence on the anodic oxidation, high temperature oxidation bath on the dissolution of oxide film increased porous anodic oxide film, the surface will increase, on the contrary, the porous anodic oxide film on the surface of the small aperture. In addition, the temperature is high, the porosity of the anodic oxide film is higher, and vice versa is lower.
Electrolytic coloring aluminium alloy is mainly metal ions in oxide coloring solution within the pores of the barrier layer on the surface of the electrochemical reduction reaction, the deposition of metallic ions in liquid coloring anodic oxide film in the bottom of the hole, the incident light scattering and showing a different color, the more material micro deposition, color more deep. The same amount of metal or metal compound is deposited on the part with high and low temperature through the same electric quantity. For the location with high porosity and large surface aperture, the average pore sediment is less.