Powder coating defects and solutions ـ poor mechanical-chemical properties

 03 August 2020   11:09
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Powder coating defects and solutions ـ poor mechanical-chemical properties

After powder application certain defects might appear on the coated part which we have elaborated along with the factors that could be responsible for causing these.

Poor mechanical-chemical properties of powder coating

  • Poor chemical and mechanical properties

Discrepancy in the chemical and mechanical properties of the applied coating with the specifications of the Technical Data Sheet (TDS)

  1. Under-cured film
  2. Presence of grease and oil on the substrate
  3. Thick phosphate layer
  4. Problem in the formulation of powder coating
  5. Using clear top coat causes the chalking effect in the coating
  6. Thick coating film

  • Poor adherence

the coating film hardly adheres to the substrate

  1. Under-cured film
  2. Improper pretreatment of part
  3. A change in the quality of part
  4. Thick phosphate layer
  5. Poor adherence of second layer

  • Poor chemical resistance

Coating has low resistance towards chemicals

  1. Under-cured film
  2. Using unsuitable powder coating
  3. Presence of holes and craters in the coating

  • Poor corrosion resistance

Poor resistance of coating against corrosion

  1. Under-cured film
  2. Improper pretreatment of substrate
  3. Presence of holes and craters on the coating
  4. Poor coating on the corners and edges of part
  5. Choosing unsuitable resin base

  • Chipping and peeling off of film

Cured film easily flakes and peels off the part

  1. Under-cured film
  2. Improper pretreatment of part
  3. Presence of rust on substrate
  4. White rust
  5. Film does not adhere to edges and corners that have been cut by laser
  6. Presence of dirt or contaminants on the surface

  • Scratch marks on the film

Poor resistance to scratches and abrasion

  1. Under-cured film
  2. Packing causes abrasion on the coated surface
  3. Easily scratched powder coating
  4. Abrasion during assembly
  5. Coated part is transported in a non-standard container

Prepared by: Mojtaba Zeinal