Adhesion problem of powder coating application
Poor adhesion is usually related to poor pretreatment or under cure.
- Undercure -Run an electronic temperature recording device with a probe on the part to ensure that the metal temperature reaches the prescribed cure index (Time at temperature).
- Pretreatment – Perform regular titration and quality checks to avoid a pretreatment problem.Surface preparation is probably the cause of the poor adhesion of the powder coating powder. Not all stainless steels accept phosphate pretreatments to the same extent; some being more reactive to the chemicals in the pretreatment process, and others being more inert. What you have written makes perfect sense. If you want better success with 316 stainless you might need to change the pretreatment chemicals to more aggressive reactants, or you might need to provide some physical profiling of the surface so that the powder coating can adhere chemically and physically.