Introduction:
Typically, it is difficult to achieve good adhesion between a paint coating and fresh steel sheet. For this reason, it is customary to apply some type of intermediate layer, a pretreatment, to develop good long-term performance. Not only does the pretreatment improve the mechanical adhesion between the paint and the zinc coating, but it also improves the resistance to blistering and loss of paint adhesion during exposure to corrosive environments. In the case of steel sheet, the need for a pretreatment to achieve good initial paint bonding is less critical, but a pretreatment is still beneficial to achieve good resistance to loss of paint adhesion when the product is exposed to a corrosive environment.