Electromagnetic interference, or EMI, is a signal from one device that disrupts the signal of another device. This signal can cause a decrease in system performance, loss of functionality, or permanent damage. EMI shielding prevents electromagnetic interference from emitting from or entering a device, providing protection from the negative effects of EMI.

Here, we will explore EMI shielding and the various types of materials it can be made from to deliver optimal protection for your devices and systems.

Understanding EMI Shielding

EMI shielding protects an electronic device from external signal interference and prevents the device from interfering with surrounding devices, ensuring all intended signals are clean and functional. EMI shielding materials are typically metallic, allowing them to conduct and absorb the interference signal before it reaches the electronic components within the protected device.

Various industries depend on EMI shielding to protect electronic devices and systems from interference. EMI shielding enables the proper functionality of consumer electronics, automobiles, satellites, medical devices, and many other electronic systems.

Types of EMI Shielding Materials

Various EMI shielding materials provide reliable protection from interference, including solid metals, conductive paints and coatings, specialized plastics, and metallic foils.


The following metals are ideal EMI shielding materials:

  • Copper: A reliable metal for EMI shielding applications, copper can reduce interference from electrical and magnetic waves with their high electrical conductivity. Copper is an ideal material for nearly every EMI shielding application and is commonly used in everything from home computers to critical healthcare equipment. However, copper can be significantly more costly than other materials.
  • Aluminum: This material offers good electrical conductivity and an excellent strength-to-weight ratio. Aluminum is more prone to oxidation and corrosion than other alloys, but it is a suitable option for applications requiring a non-ferrous EMI shielding material. Aluminum offers about 60% of the electrical conductivity of copper, but it is less expensive.
  • Steel: Various types of steel, including stainless steel, carbon steel, and other steel alloys, are suitable EMI shielding materials. Carbon steel offers magnetic shielding and can be pre-tin plated to protect against low-frequency EMI and corrosion at a low cost.

Conductive Coatings and Paints

Conductive paints and coatings can give EMI shielding properties to materials that typically do not provide shielding, such as drywall and wood.

  • Silver-filled coatings: This smooth and brightly colored coating offers exceptional conductivity and adhesion to various plastics and metals. Silver-filled coatings can comply with UL requirements and work for EMI shielding on medical, scientific, military, and industrial equipment as well as personal computers and mobile device enclosures.
  • Nickel-based coatings: Nickel-based coatings offer excellent corrosion resistance and are available in easy-to-apply liquid and aerosol formats. Its mild solvent composition is safe for use on polystyrenes, contains no hazardous air pollutants (HAP), and can comply with UL requirements. Nickel-based coatings are ideal for marine EMI shielding applications and can coat plastics, wood, and drywall.
  • Graphite-based paints: These paints offer low surface resistivity, high conductivity, durability, good adhesion, and corrosion resistance. Graphite-based paints resist rub-off and weather and are a cost-effective solution for low-frequency EMI shielding. They can be applied to wood, drywall, metal, glass, and plastics.

Conductive Plastics and Polymers

Plastics and polymers can be made to conduct electrical and magnetic signals to provide EMI protection. The following plastics and polymers are used in EMI shielding.

  • Carbon-filled plastics: This EMI shielding option synthesizes the benefits of traditional metals as well as the reduced weight, better flexibility, and enhanced corrosion resistance of plastics. Carbon-filled plastics are cost-effective solutions for critical applications requiring design flexibility, including military, medical, aerospace, and consumer electronics equipment.
  • Metal-coated polymers: Metal-coated polymers are lightweight, versatile plastics with conductive EMI shielding properties. They are typically more cost-effective and flexible in design than solid metal shields.

EMI Shielding Expanded Metal Foil

The EMI shielding effectiveness of a conductive material depends on the thickness and type of material, the strength and frequency of the electromagnetic signal, and the design of the shield itself. Although thick, solid conductive materials tend to offer superior shielding, they can also be heavier and more costly. EMI shielding with expanded metal foil offers a cost-effective, lightweight alternative to solid metal shields.

Made from copper, aluminum, or other conductive metal, expanded metal foil is versatile, flexible, and malleable, allowing the user to install the foil around the surface of various objects. The expanded metal foil prevents EMI from harming the protected device and surrounding electronics.

Precision expanded metal foils from CThru Metals conduct the interfering signal across the surface of the material, maintaining the functionality of wires, cables, gaskets, enclosures, electrical systems, carbon fiber products, and more. It is a reliable, lightweight solution, especially in demanding aerospace and defense industry applications.

Protect Your Electronics With CThru Meshâ„¢ Precision Expanded Metal Foils

EMI is a disrupting signal from nearby sources that can interfere with sensitive electrical components. EMI shielding can prevent the harmful effects of electromagnetic interference by conducting the interfering signals and carrying them away from the sensitive components. There are various EMI shielding materials available, including solid metals, coatings, paints, specially designed plastics, and expanded metallic foils.

CThru Metals manufactures precision expanded metal foils for cost-effective, lightweight EMI shielding in various applications. Based on your specific application, we can customize your custom EMI shielding foil by thickness, material, opening dimensions, number of openings, and more. Contact us or request a quote for more information about CThru Meshâ„¢ precision expanded metal foils.

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