The chrome-free pretreatment
It is well known now that some well described Qualicoat pretreatment procedures are very critical in obtaining good adhesion of powder coating and sufficient corrosion protection.
Proper etching/pickling to remove the most sensitive Aluminium top layer and sufficient rinsing are two of these important pretreatment steps.
Even though job coaters are following Qualicoat procedures most of the time when adhesion or corrosion issues occur the failure can be found in the pretreatment steps and not in the conversion bath or in the powder coating cycle. It seems that the newly developed Cr (VI) free conversion coatings are less forgiving than former chromate conversion coatings.
AD Chemicals and her customers are working closely together to determine the critical pretreatment steps. Pickling, racking and rinsing procedures can be optimized to guarantee the best performance possible with Cr(VI) free conversion coatings.
In this presentation we will discuss some factors
that might influence the quality of your powder coated aluminium.
Introduction
Each powder coating line has it´s own challenges. You have to be aware of the best processes prior to the painting of Aluminium objects. The starting point must be that a
The ultimate goal is to work with Chromium (VI) free pretreatments while maintaining the quality properties between Aluminium and paints. Also to meet the required specifications of Qualicoat.
First let’s focus on the variables of the pretreatment line and the quality of the Aluminium.
