Phosphating

Phosphating is a key pretreatment procedure. Its core functions are to improve the adhesion of subsequent coatings, enhance corrosion resistance and optimize the surface microstructure. The phosphating film is a chemical conversion film (non-electroplated layer) with a typical thickness of 0.5–5μm and gray/blue-green appearance. It has no decorative effect and is only used for functional substrate protection

1. Tank Solution Preparation

Dilute the phosphating agent with water at a ratio of 1:20, temperature: 25–40℃ (normal & low temperature phosphating system).

2. Core Phosphating Operation

Small zinc alloy parts are uniformly treated by immersion method, suitable for workpieces with complex structures, small holes and gaps. 1.Load the workpieces into dedicated plastic hanging baskets or stainless steel hangers, and fully immerse them in the phosphating tank solution to ensure full contact of all surfaces with the solution; 2.Soak at constant temperature for 20–60 seconds, and lift the workpiece gently 2–3 times during the process to discharge trapped air bubbles in gaps and blind holes and prevent missing phosphating; 3.Take out the workpiece stably after soaking, and check that a uniform and delicate gray phosphate conversion film is formed on the surface.

3. Post-phosphating Treatment

Rinse the workpieces with running clean water to completely remove residual phosphating solution on the surface.

4. Remove Surface Moisture

Place the workpieces into the machine to thoroughly remove surface moisture. High-temperature baking is strictly prohibited, as it may cause coating cracking and substrate deformation.