Phosphating chemicals bring on a corrosion-resistant zinc layer on the metal. It helps for the gripping of the paint or powder for an improved bond.

7 Tank Phosphate Treatment Process

Stage 1 – Degreasing: For uniform coating, all metals to be zinc phosphate should be free from grease, oil, any other foreign matter. Alkali and emulsifiable cleaner are used for this stage.

Stage 2 – Water Rinse: Water rinsing is very important to avoid contamination in the subsequent stages and to get high performance of the coating.

Stage 3 – De-rusting: When the removal of rust and light scale from the surface cannot be achieved by sanding, acidic chemical cleaners are commonly used. All metal to be phosphate should be free from rust & scale. Acidic de-rusting chemicals are used for this purpose.

Stage 4 – Water Rinse & Activation: This stage is prior to the phosphate process that promotes the formation of a dense, fine-grained phosphate coating, which offers superior adhesion and durability to the paint finish, in corrosive environments.

Stage 5 – Phosphating: This stage is the deposition of zinc phosphate crystalline coating on the metal surface. The article to be coated comes in contact with a zinc solution. Due to a complex chemical reaction with the metal surface, and insoluble tertiary zinc phosphate coating is deposited. This coating acts as a base to improve paint adhesion to the metal

Stage 6 – Water Rinsing: It is made sure that before shifting to stage7, it is properly rinsed.

Stage 7 – Passivation: After rinsing, the article is treated in a Passivation solution. This treatment increases the corrosion resistance of the phosphate coating and is dryed.