Seven Tank Phosphating chemicals for Powder Coating - A Seven Tank Phosphating Process is a widely used pretreatment method in powder coating, especially for mild steel substrates. It improves adhesion, corrosion resistance, and overall performance of the powder coating. Each tank contains a specific chemical treatment, and the process involves sequential dipping or spraying. - Here’s a typical 7-tank phosphating chemical sequence: 1. Degreasing (Alkaline Cleaner) - Purpose: Removes oil, grease, and other organic contaminants. - Chemical: Alkaline degreaser (e.g., sodium metasilicate, sodium hydroxide) 2. Water Rinse (First Rinse) - Purpose: Removes residual alkaline chemicals. 3. Water Rinse (Second Rinse) - Purpose: Ensures complete removal of degreaser. 4. Derusting (Acid Pickling – if rust is present) - Purpose: Removes rust and mill scale from metal. - Chemical: Diluted phosphoric or hydrochloric acid 5. Activation (Optional, if used before phosphating) - Purpose: Enhances crystal formation in phosphating. - Chemical: Titanium-based activation solutions 6. Phosphating - Purpose: Creates a phosphate conversion coating for better paint adhesion and corrosion resistance. - Chemical: Zinc or iron phosphate solution 7. Water Rinse (Post-Phosphating Rinse) - Purpose: Removes excess phosphate sludge and loose residues. 8. Passivation (Final Rinse) - Purpose: Improves corrosion resistance, neutralizes surface. - Chemical: Chromic or non-chromic passivation (e.g., trivalent chrome or organic sealers). #Seven Tank Phosphating chemicals for Powder Coating Manufacturer.