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Substances in Common Use — Science STD 9 — Question

Maharashtra BoardEnglish MediumSTD 9ScienceSubstances in Common Use5 Marks
Question
Explain how powder coating is done.
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Answer

  • Powder coating is a method of applying a layer harder than paint on the surface of an iron object to prevent rusting.
  • In this method, a polymer resin, a pigment and some other ingredients are melt, mixed, cooled and ground into a uniform powder.
  • This powder is sprayed on the polished metal surface by electrostatic spray deposition (ESD).
  • In this method, the particles of the powder are given an electrostatic charge due to which a uniform layer of the powder sticks to the metal surface.
  • Then the object is heated in the oven along with the coating.
  • A chemical reaction occurs in the layer, resulting in the formation of long cross-linked polymeric chains.
  • This powder coating is highly durable, hard and attractive.
  • Powder coating can be done on plastic and medium density fibre (MDF) board in day to day use as well.

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