Phosphate coatings are typically used on steel parts to prevent corrosion, aid in lubrication to prevent wear of the part in high friction situations or can be used as a pretreatment foundation before coating or painting. Manganese, iron and zinc are the main kinds of phosphate coatings.
A typical phosphating procedure begins with cleaning the workpiece's surface, rinsing, surface activation, and phosphating. During this final step, the part is submersed into phosphoric acid causing a chemical reaction which in turn adjusts the pH of the solution. This causes the dissolved salts to fall out of the solution and bond to the part. The part is then rinsed, dried, and the application of supplemental coatings can be applied such as lubricants, sealers, oil, etc.
Common parts that use manganese phosphating include automotive parts such as gears, leaf springs, clutches, and engine components.
|1. Degreasing||2. Rinse|
|3. Pickling||4. Rinse|
|5. Activation||6. Manganese Phosphate|
|7. Rinse||8. Drying|