Why Do We Choose Anodic Oxidation?
Anodic oxidation process is a traditional technology to form an oxide film by electrolytic oxidation on the surface of metals and alloys. The oxide film made by this technology has uniform color, corrosion resistance, strong binding force and good biocompatibility, which has been widely used in the field of modern biomedicine and aerospace.
The anodizing process of titanium is to use titanium as the anode, stainless steel and other metals as the cathode, with the help of a certain electrolyte, through electrochemical reaction to promote the surface of titanium alloy oxidation reaction and the formation of oxide film. This layer of oxide film on light reflection and refraction is very obvious, and different thickness of oxide film will show different colors, at the same time has protection, such as our EDC Tools or Camp Accessories. So it is an ideal decorative layer and wear-resistant layer. It is widely used in architecture, aviation, medicine and other fields.
The anodic oxidation coloring process of titanium and its alloy is as follows:
Oil removal is to remove the oil remaining on the surface of titanium during rolling. Because of the poor permeability of the attached part of the oil, it is easy to appear uneven coloring phenomenon when pickling the titanium surface.
The initial pickling is done to form a pear skin pattern on the surface of titanium and its alloy. Using 5% concentration of hydrofluoric acid to pickling titanium can promote the formation of pear skin pattern.
The secondary pickling is to remove the powdery dirt formed on the surface by the initial pickling. In addition, in order to avoid uneven pickling, it is necessary to use hydrofluoric acid to make titanium ions into a titanium containing complex to achieve stability after hydrofluoric acid dissolves surface dirt once.
The electrolyte with 1% weight concentration of phosphoric acid was used for constant voltage treatment with aluminum plate as cathode and titanium plate after pretreatment as anode. As the voltage rises, the oxide film on the titanium surface thickens, thus showing a variety of different color changes.
In order to improve the corrosion resistance, anti-pollution and wear resistance of the anodized film, titanium and its alloys need to be sealed with hot water, steam, and a solution containing inorganic salts and organic substances after anodic oxidation and coloring.
After closure, wipe the moisture on the workpiece with a clean cotton cloth and let it dry naturally.
In summary, it can be seen that the anodic oxidation process of titanium and its alloy is relatively simple, and the color formed on the surface is rich, coupled with the relatively low cost, so it is easy to be popularized in industry, and it is a kind of oxidation coloring technology with good development prospects.