• Electrically Conductive Coatings

Plastic housings used to enclose electronic equipment are electrically non-conductive. However, it is vital to ensure that the working components are effectively shielded from incoming interference signals, as well as preventing outgoing transmission to other equipment.

A number of technologies have been developed to provide electrical conductivity within the structure of the housings.

Electrically Conductive Fillers

​The obvious method of adding a conductive filler to the basic plastic resin from which the component is made has significant disadvantages:

  • Significantly increases the weight of the moulding.
  • Increases the molten viscosity of the plastic, making moulding more difficult.
  • Can be detrimental to the physical properties of the plastic.

Electrically Conductive Coatings

It has become common practice to apply electrically conductive coatings, usually to the insides of mouldings. A ​number of different processes have been used commercially during the last three decades in which shielding technology has been developing, including:

  • Electroless nickel plus copper
  • Flame sprayed metallic coatings
  • Metallic foil
  • Paint

Electrically Conductive Paint

Over the last three decades electrically conductive paint has been found to be the most commercially successful coating process for the following reasons:

  • Provides high performance shielding effectiveness.
  • Can be deposited, using conventional equipment and techniques, onto the surfaces of very complex shapes.
  • Capital costs are low.
  • With the conductive pigment only used in the coating, it is far cheaper than filling the whole component.

Metal Paint Coatings

A number of electrically conductive metals have been used in this type of coating, including:

  • Copper has excellent conductivity but relatively poor durability due to its tendency to corrode.
  • Silver is excellent in all aspects but it is an expensive option.
  • Nickel provides an excellent combination of the required properties, shielding performance and durability, and is also highly compatible when incorporated into paint formulations. Nickel metal is readily available in small particle forms and, in addition, there are three distinctly different morphologies – spherical powders, filamentary powders, and flakes.

For more information on electrically conductive coatings, please contact us.

 

Electrically Conductive Products Available from Hart Materials

Novamet Conductive Nickel Flake Grade HCA-1

Novamet Nickel Powders Type 525

Vale Nickel Powder Type 255

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