EMI stands for electromagnetic interference. Electromagnetic energy can come from many sources and without proper protection, can result in the failure of certain electrical systems. EMI shielding gaskets can protect electronic systems against electromagnetic interference.
To achieve proper EMI shielding, a product typically needs to use a certain amount of metal. Silver, aluminum and copper are the most common metals used in EMI shielding applications.
Electrically Conductive Silicone & Fluorosilicone
This is probably the most common and widely used EMI material. These products offer the benefits of silicone (high operating temp, thermal stability, flame retardant, good chemical resistance) with added metal particles to create EMI protection. Common additives to solid silicone used to create EMI shielding are as follows:
- Silver – extremely conductive, but high cost
- Silver-plated aluminum – very conductive, but less cost than pure silver
- Silver-plated copper – very conductive, but less cost than pure silver
- Nickel-plated graphite – moderate shielding at less cost than silver products
- Carbon black – Generally least expensive, but less shielding effectiveness than graphite or silver
- Fabric reinforced EMI silicone - In certain instances, conductive silicone products can also be provided with a fabric layer insert that provides further EMI protection as well as added stability.
- Conductive PSA – Depending on the application, we can supply a conductive adhesive on one of both sides of a part. Both acrylic and rubber options exist for conductive PSA.
Sponge Rubber Material
Certain applications require the use of a softer material than solid silicone. In these cases, products are made with silicone sponge or other sponge rubber and other metal additives. These products can be used in circuit boards or other applications where compression is needed or air gaps are a concern.
Copper, Silver & Aluminum Foils
Sometimes these metals are offered by themselves in very thin forms as an EMI material. These materials are directed for specific EMI shielding purposes. They can be offered alone or used as a wrap to enclose sponge rubber or other material.