EMI Shielding Materials for EMI Shielding Gaskets
EMI shielding materials are used to provide an electrically conductive seal for electronic equipment openings and housing covers to prevent or restrict electromagnetic interference in EMI shielding gaskets. There are many types of EMI shielding materials and solutions available to the designer. Stockwell Elastomerics' EMI shielding materials are an extension of our silicone rubber capabilities - EMI gaskets can be die cut, water jet cut or compression molded from electrically conductive silicone rubber compounds.
Visit the ESD, EMI, and Electrically Conductive Materials Technical Data Sheets for detailed technical information on these materials.
Conductive Silicone Rubber EMI Shielding Gasket Material
The main advantage of EMI shielding gaskets fabricated from conductive elastomers is the combined benefit of environmental sealing over a broad temperature range along with EMI shielding. This EMI gasket material is typically silicone rubber or fluorosilicone rubber with embedded silver plated aluminum particles, silver plated glass beads, silver plated copper particles, nickel-graphite particles or conductive carbon. Many of these EMI shielding materials meet the properties of Mil-G-83528B. Conductive silicone rubber materials are typically molded into sheets from .010" to .125" thick and 12" x 12" to 10" x 15" in size and then die cut or water jet cut to the final gasket configuration. A partial listing of available compounds follows.
Compressible (Softer) Conductive Nickel-Graphite Filled Silicone Gasket Material
Rogers Corporation's EC2130 and EC2040 nickel-graphite filled silicone rubber is a compressible 30 and 40 durometer conductive gasketing material. Application of 3M #9713 conductive fabric supported acrylic adhesive provides both a conductive adhesive surface for EMI shielding integrity and dimensional stability to reduce tears during handling and assembly.
EMI Absorbing Material
Thin flexible high performance EMI absorbing materials differ from conductive materials. Rather than "harnessing", capturing and grounding the EMI energy, EMI absorbing materials convert the EMI energy into heat that is dissipated. Proper attenuation may be achieved through various material thicknesses. The attenuating material in the MG series is magnetic metal. Parts are typically waterjet cut to obtain optimum yield but may also be die cut. Various adhesives are available to meet specific application needs.
Oriented Wire in Silicone Rubber
Stockwell Elastomerics has partnered with a supplier of silicone impregnated oriented mesh products to provide .030", .062" and .125" thick solid silicone rubber shielding products. These gasketing materials tend to be less costly than conductive silicone materials, with EMI properties provided by oriented Monel mesh (QQ-N-281) and Aluminum mesh (AMS-4182, alloy 5056).
Conductive Adhesive Backings
Stockwell Elastomerics applies conductive metal fiber filled acrylic adhesive backings to many conductive EMI gasket materials.
Common MIL-G-83528C fill and polymer specifications
- Type A = Silver coated Copper - Silicone (65 Durometer)
- Type B = Silver coated Aluminum - Silicone (65 Durometer)
- Type C = Silver coated Copper - Fluorosilicone (75 Durometer)
- Type D = Silver coated Aluminum - Fluorosilicone (70 Durometer)
- Type M = Silver coated Glass - Silicone (65 Durometer)
EMI Shielding Material Conductivity Video
This video offers a simple visual demonstration of the conductivity of various EMI shielding gasket materials. The tan material in the video has silver coated aluminum particles, the dark grey material is nickel coated graphite. The last example shows a 3M conductive adhesive where the conductive path flows through the metal plate, up through the adhesive, through the conductive material into the LED.
Contact Stockwell Elastomerics for EMI Shielding Materials
EMI Shielding Materials
ESD, EMI, and Electrically Conductive Materials Technical Data Sheets
Listing of Pressure Sensitive Adhesives
3M9713 - 3 Axis Electrically Conductive Tape