Main aims in the pretreatment to metal surface before coating

The main aims in the preparation of a metal surface before powder coating may be defined as follows:

  1. The conditioning of the surface so as to render it suitable for the coating that is to be applied
  2. The complete removal of all foreign matte,e.g,scale,grease,cutting oil,soil,welding splatter,etc
  3. The pretreatment should impart uniformity throughout all treated workpiece surfaces,irrespective of the source of the metal or of the contaminants that might adhere.

As with other methods of organic finishing attention to the pretreatment stage is essential in order to achieve the full potential of the powder coatings.

Surface pretreatment may vary depending upon the specific end use requirements of the finished products,from a single-step cleaning operation to a multi-stage sophisticated pretreatment which deposits a conversion coating on the surface of the metal.