7 Tank Phosphating: A Surface Treatment Process for Metal Components

Phosphating is a surface treatment process that is used to improve the corrosion resistance and paint adhesion of metal components. One of the most commonly used methods of phosphating is the 7 tank process, which involves seven separate stages to achieve the desired results.

1. Degreasing: In the first stage, the metal components are cleaned of any oil, grease, or other contaminants that could interfere with the phosphating process.

2. Pickling: The components are then treated with a solution of an acidic pickling agent, such as hydrochloric acid, to remove any rust, scale, or other impurities from the surface.

3. Rinsing: After pickling, the components are rinsed thoroughly to remove any residual acid and impurities.

4. Activation: The components are then treated with an activation solution that helps to prepare the surface for the next stage of the process. This solution usually contains a mixture of acid and a metal salt, such as iron or zinc.

5. Phosphating: The components are then treated with a solution containing phosphoric acid and a metal salt. This solution reacts with the surface of the metal to form a layer of phosphate crystals, which provide improved corrosion resistance and paint adhesion.

6. Rinsing: After phosphating, the components are rinsed thoroughly to remove any residual phosphating solution and impurities.

7. Passivation: In the final stage, the components are treated with a passivating solution that helps to improve the durability and stability of the phosphate layer.

The 7 tank process is widely used for a variety of metal components, including steel, aluminum, and zinc, and is suitable for both small and large production runs. Phosphating provides a durable, long-lasting surface treatment that can help to extend the service life of metal components and improve their overall performance and appearance.