Titanium alloy color anodizing process brief introduction

Titanium anodizing-The anodic oxidation process of titanium and titanium alloys uses titanium as the anode, stainless steel and other metals as the cathode, and with the help of a certain electrolyte, the oxidation reaction occurs on the surface of the titanium alloy through an electrochemical reaction to form an oxide film. This layer of oxide film has a very obvious effect on the reflection and refraction of light, and the oxide film of different thicknesses will show different colors, and it is also protective. Therefore, it is an ideal decorative layer and wear-resistant layer, and is widely used in construction. , aviation, medicine and other fields.

Titanium alloy color anodizing
Titanium alloy color anodizing

Titanium alloy color anodizing process flow

The anodic oxidation coloring process of titanium and its alloys is as follows:

Degreasing (strong alkali degreaser) → water washing → initial pickling (hydrofluoric acid aqueous solution) → water washing → secondary pickling (hydrofluoric acid + hydrogen peroxide aqueous solution) → water washing → anodizing (constant voltage in phosphoric acid aqueous solution) electrolysis)→washing→sealing→drying.

  1. Degreasing: Degreasing is to remove the oil remaining on the titanium surface during rolling. Because the oil-adhered part has poor water permeability, uneven coloring is prone to occur when pickling the titanium surface.
  2. Initial pickling: Initial pickling is to form pear skin patterns on the surface of titanium and its alloys. Washing titanium with hydrofluoric acid with a concentration of 5% by weight can promote the formation of pear skin patterns.
  3. Second pickling: The second pickling is to remove the powdery dirt formed on the surface by the first pickling. In addition, in order to avoid uneven pickling, it is necessary to use hydrofluoric acid and hydrogen peroxide aqueous solution to make titanium ions become a titanium-containing complex to stabilize after the hydrofluoric acid dissolves the surface dirt once.
  4. Anodizing: Use phosphoric acid with a concentration of 1% in the electrolyte, use the aluminum plate as the cathode, and the pretreated titanium plate as the anode for constant voltage treatment. As the voltage rises, the oxide film on the titanium surface thickens, showing various color changes.
  5. Sealing: 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.
  6. Drying: After sealing, wipe off 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 alloys is relatively simple, and the colors formed on the surface are rich, and the cost is relatively low, so it is easy to be popularized in industry, and it is a kind of good development prospect. Oxidation coloring technology.

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