Pretreatment means surface preparation for the post treatment to be applied on the surface of metals. Surface preparation includes:-

Mechanical Method: includes methods like scratch brushing and sand blasting. This abrasive action not only removes the surface Impurities but also eliminates scratches and surface irregularities. This approach can yield a clean surface however not protected surface from corrosion and rust.

Chemical Method: includes removal of dirt, oil and grease, and the oxides present on the surface using chemicals. The chemicals may be applied by wiping, spraying or dipping. The nature of chemicals used depends upon the base metal and will be discussed later in detail. The chemicals treat the surface to give corrosion resistance and prepared surface for post finishing.

The aim of the pretreatment chemicals is to:

1. ) Clean and prepare the surface for post finishing.
2. ) Give Adhesion and corrosion resistance of paints on metals surface
3. ) Provide protection against rust and corrosion.

Sum up of all Categories Process:

1. Cleaning:
   
   1. Alkaline
   2. Acid
2. Phosphating
   
   1. Iron Phosphating
   2. zinc Phosphating
   3. Manganese Phosphating
   4. Nickel Phosphating
3. Alumimium Treatment
   
   1. Powder Coating
      
      1. Chromating
      2. Chrome Free
   2. Anodizing
4. Coil Coating
   
   1. Chromating
   2. Chrome free
5. Passivation
6. Additives
7. Paint Stripper