In fact, under the conditions of 160 degrees and 180 degrees, the corrosion resistance of cured coatings is quite different. I think the main reason is that epoxy resin and curing agent are not cured completely at 160 degrees.

I am powder paint. When dicyandiamide or carboxyl polyester resin is used to cure bisphenol A epoxy resin, the curing condition is 180 degrees 15 minutes. If the temperature or time is not enough, the mechanical properties and corrosion resistance of the coating will be poor.

The combination of metal powder and polymer interface can be seen by scanning electron microscope.