How Are Colored Titanium Screws Made?

Colored titanium screws only change the screws into different colors through surface treatment processes. Take black titanium screws as an example: their surface is coated with a black layer. First, the "black coating" process, commonly known as "blackening by boiling", is carried out. Specifically, the screw fasteners are directly put into a chemical agent and boiled, so that a black oxide film is formed on the surface of the screws. After this process, the finished product has a very attractive appearance, but its corrosion resistance is not strong. Therefore, additional surface oxidation treatment is required. Oxidation blackening is also a relatively common surface treatment method. In this anti-loosening treatment, the screw fasteners are placed in a strong oxidizing chemical solvent, and after a period of time, a beautiful and dense black iron oxide film is formed, which also provides corrosion resistance.

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1. Pre-treatment: Cleaning and Preparation

This is the most critical step, which directly determines the uniformity and quality of the final color.

Precision Cleaning

Put the already processed and formed titanium screws into an ultrasonic cleaner, and use organic solvents (such as acetone, alcohol) to thoroughly remove oil stains, fingerprints and any impurities on the surface.

Grinding and Polishing

According to the required final effect, mechanical polishing or electrolytic polishing of the screws may be necessary to obtain a very smooth and flawless mirror-like base. The smoother the surface, the more uniform and vivid the color will be.

2. Anodizing Treatment

This is the core coloring process and needs to be carried out in a special electrolytic cell.

Preparing the Electrolyte

Diluted phosphoric acid, sulfuric acid, triethanolamine, etc., are usually used as the electrolyte. Different electrolytes will produce slightly different color effects.

Establishing the Circuit

• Use the cleaned titanium screws as the anode and connect them to the positive electrode of the power supply.
• Use a piece of inert metal (such as a platinum sheet or titanium sheet) as the cathode and connect it to the negative electrode of the power supply. Immerse both the anode and the cathode in the electrolyte.

Electrifying for Oxidation

• Turn on the DC power supply and slowly and accurately increase the voltage.
• The voltage is precisely controlled by the power supply and increased gradually. As the voltage rises, an oxide film begins to form on the surface of the titanium anode, and the thickness of the oxide film increases linearly with the increase of voltage.

Color Precisely Controlled by Voltage

• Low voltage produces a thin oxide film, corresponding to colors such as blue, gold, and purple.
• Medium voltage produces an oxide film of medium thickness, corresponding to colors such as dark blue, purple, and green.
• High voltage produces a thick oxide film, corresponding to colors such as green, pink, and yellow.