Anodizing: aluminium and its alloys are used as anodes, and lead or graphite are used as cathodes. In a certain concentration( such as sulfuric acid, oxalic acid, chromic acid, etc.) conductive solution, through applied voltage and the effect of electric current, a certain thickness (8-12um) layer is formed on the surface of the firm, which has good mechanical properties, hardness, corrosion resistance, wear resistance, insulation, adsorbability and so on.
1. Degreasing: organic solvent degreasing, water based emulsification cleaning agent degreasing, electrochemical degreasing.
2. Chemical polishing: Further removing the dirt on the surface of aluminum and its alloy with phosphoric acid, and removing the natural oxide film on the surface of the aluminum alloy, so that the aluminum substrate is exposed to facilitate subsequent anodization. At the same time, the polishing also has the effect of leveling, which can further smooth the surface of the workpiece after sandblasting, and the surface texture is better.
3. Peeling black film: After phosphorylation, a black-gray film (metal such as copper, nickel, manganese, iron, silicon, etc., which is insoluble in phosphoric acid) remains on the surface of the workpiece, and then treated with nitric acid.
4. Oxidation: The process of forming an oxide film on an aluminum product (anode) under the action of an applied current under the corresponding electrolyte and specific s conditions. Anodic oxidation, if not specified, usually means Anodizing sulfuric acid.
5. Dyeing: Dyeing should be done immediately after the anode and not too long. After oxidation, carefully rinse off the residual acid with cold water (avoid the temperature rise and the membrane is automatically sealed).
6. Sealing: high temperature boiling water seals the pores, and alumina combines with water molecules to form hydrates, forming crystals.
7. Drying: Place the product in an oven with the oven temperature set at 70 °C. The sealing temperature should not be too high, otherwise the film is prone to cracks. Before washing, it must be washed with hot water to increase the temperature of the workpiece so that avoiding to crack caused by the workpiece being too cold.
Post time: Jan-09-2019