New Conversion Coating Technologies

Traditionally, conversion coating pretreatment process options have been limited. For the most part, they include either an iron or zinc phosphate. Although these have been sufficient in performance in the past, concerns have recently risen regarding their inefficient energy and water usage. Iron Phosphate Pretreatment Systems Iron phosphate systems are most often used when a durable finish is required but the parts are not exposed to extremely corrosive environments. These systems involve up to six stages, including multiple cleaning and rinsing phases which require a lot of water and energy. Zinc Phosphate Pretreatment Systems Zinc phosphate coatings provide exceptional durability even in corrosive environments and they are capable of coating mixed metals. However, zinc phosphate systems require even more phases than iron systems. Zinc phosphate systems are different in a couple ways from an iron system. Primarily, the zinc system requires a surface conditioner stage, which happens just before the zinc phosphate stage. Since the surface conditioning chemistry is a colloidal suspension, it ages over time and must be dumped frequently to be effective. Again, wasteful in energy and water.