FUNCTION OF FINAL (SEAL) RINSES IN A PHOSPHATING OPERATION

摘要

The process of treating metal substrates prior to painting usually comprises several steps. The choice of pretreatment typically depends on the type of metal that is being used and final requirements of the painted metal article. All pretreatment steps serve an important function, but the final rinse step (commonly referred to as the seal rinse) can have a significant impact on the system's paint adhesion and corrosion resistance. Pretreatment choices are many, but phosphating is a common one for steel-based substrates. The phosphating process can be carried out using many methods, but the most familiar approaches found in industrial operations are three- and five-stage systems in the case of iron phosphating. In zinc phosphating processes six stages are normally considered the minimum, but as many as 11 pretreatment steps are not uncommon.