emi gaskets | silver aluminum silicone | emi gasket | rf gasket

EMI Gaskets

SSP fabricates EMI gaskets from the shielding silicones and fluorosilicones that we make.

Choose standard or custom products from the following material types.

  • MIL-DTL-83528 QPL Certified
  • Corrosion Resistant
  • Low Shore A/Soft
  • Fuel & Solvent Resistant
  • Low Outgassing (ASTM E595)
  • Most Electrically Conductive
  • Flame Retardant (UL 94V-0)
  • Reinforced
  • Most Cost Effective
  • Non-Silicone Based

What are EMI Gaskets?

EMI gaskets provide shielding against electromagnetic interference (EMI), environmental sealing, and thermal insulation. They are used in electrical and electronic enclosures for military and civilian applications. SSP’s EMI gaskets are made of silicones or fluorosilicones that are filled with metal or metal-coated particles to provide electrical conductivity. 

Ask SSP for standard or custom EMI gaskets, including M83528 part numbers. We offer low minimum order quantities (MOQs) and quick turn-around times for cut or molded parts. Compare our materials to Parker Chomerics CHO-SEAL, Nolato Jabar, and W.L. Gore products. 

How Do EMI Gaskets Work? 

EMI gaskets seal the gap between two mating surfaces, such as a housing and a lid, in an enclosure. Like other types of environmental seals, they keep out the external environment or seal-in to prevent leakage. What makes EMI gaskets different is that they also seal against conducted or radiated EMI that can interfere with circuits.

When this electromagnetic “noise” reaches the EMI gasket, the signals are negated and the resulting electrical current is sent to ground. Silicone is normally an electrical insulator rather than an electrical conductor, but the addition of metal particles imparts the necessary electrical conductivity.

What are EMI Gaskets Made of?

EMI gasket materials from SSP use silicone or fluorosilicone as the base elastomer. They are filled with metal, metal-coated, or bimetallic materials that impart electrical conductivity. 

  • Silicone EMI gaskets are used because of their wide temperature range, flexibility, and cost effectiveness. They are suitable for enclosures where shielding and weather resistance are equally important.
  • Fluorosilicone EMI gaskets combine electrical conductivity with exceptional resistance to fuels, solvents, and aggressive chemicals. These EMI gaskets are the material of choice for aerospace, defense, and industrial applications exposed to hydraulic fluids or jet fuel.
  • Electrically conductive fillers include silver-aluminum, silver-copper, silver-nickel, nickel-aluminum, and nickel-graphite.

Video: EMI Shielding Webinar

How are EMI Gaskets Fabricated?

SSP fabricates EMI gaskets from EMI silicone sheets and EMI silicone rolls in standard and custom sizes. We also fabricate gaskets from EMI extrusions and ready-to-mold compounds. SSP can flash cut, die cut, or compression mold EMI gaskets from the shielding silicones that we make. SSP can also apply pressure-sensitive adhesive (PSA) backings for ease-of-installation. Gaskets that are cut from EMI extrusions can be cold bonded or hot spliced.

  • Flash cut EMI gaskets use CNC equipment to cut EMI elastomers into specific shapes without custom tooling. Flash cutting is ideal for rapid prototyping and short runs, and this gasket fabrication method produces extremely smooth edges with minimal loss of material. This digital manufacturing process works from your CAD file and supports flash cut EMI gaskets with a conductive PSA.
  • Die cut EMI gaskets are cut into specific shapes from sheets or rolls of EMI silicones and fluorosilicones. SSP makes its own dies in-house and fabricates die cut EMI gaskets with a high degree of uniformity, even across higher volumes. Precise dimensions, parts nesting, and punched holes with specific radii are readily achievable. SSP can also apply conductive pressure-sensitive adhesive (PSA) tapes to die cut EMI gasket materials for peel-and-stick parts.
  • Molded EMI gaskets are produced using compression molding, a process that places a preformed rubber material into the cavity of a heated mold. Standard EMI gaskets in M83528 slash sizes and custom molded EMI gaskets are available. SSP makes its own molds in-house and produces compression-molded EMI gaskets using the same materials that we supply as sheets, rolls, and extrusions. For large picture-frame style gaskets, molding can increase material yields and reduce material waste.
  • Cold bonded EMI gaskets re joined by using an RTV silicone adhesive or a non-silicone glue. Using a non-conductive adhesive increases the risk of EMI leakage, but conductive glues are available. With non-silicone glues, acrylic adhesives lack the temperature resistance of silicones.
  • Hot spliced EMI gaskets are joined by applying heat and pressure. A splicing tool, or mold, is required, but hot spliced EMI gaskets have consistent properties throughout. They don’t have a “hard spot” like with a cold bonded EMI gasket either.

What are the Technical Standards for EMI Gaskets?

EMI gasket standards include requirements for EMI shielding and environmental sealing. Some standards, such as NEMA and IP ratings, apply only to environmental sealing but may still affect EMI gaskets made of electrically conductive silicones. In addition to NEMA, the following organizations maintain standards that EMI gasket designers may need to meet.

  • U.S. Department of Defense (DoD)
  • Underwriters Laboratories (UL)
  • ASTM International (ASTM)

DoD Standards

For some military applications, EMI gaskets must use materials that meet MIL-DTL-83528 requirements. MIL-DTL-83528 is a detail specification from the DoD that establishes general requirements for electrically-conductive elastomeric shielding gaskets. MIL-DTL-83528 contains lettered sections, each of which contains requirements for the base elastomer, durometer, fill material, plane wave shielding effectiveness, and continuous use temperature. Because MIL-DTL-83528 only applies to fill materials that are pure silver or silver-coated, it does not encompass nickel-graphite filled silicones or wire-oriented silicones that contain Monel or aluminum mesh.

UL Standards

UL maintains two flammability standards that may apply to EMI gaskets: UL 94 V0 and UL 50-E. Neither standard is silicone-specific, and both apply to plastics. UL 94 V-0 is part of a larger standard, UL 94, that classifies materials according to how they burn in various orientations and part thicknesses. UL 50E is an IP standard against dust and water that applies to enclosures for electrical equipment that will be installed and used in non-hazardous locations.

ASTM Standards

For EMI gaskets that require resistance to galvanic corrosion, such as those used in marine environments, ASTM B117 may apply. Galvanic corrosion occurs when two dissimilar metals are immersed in a conductive solution, such as salt water, and are electrically connected. There are also electrically conductive silicones for EMI gaskets that need to meet ASTM E595 for outgassing, a problem in high vacuum environments, such as outer space, where released gases can condense upon and cloud optics. 

Video: Tooling for EMI Gaskets

This video shows how SSP’s in-house machine shop makes the tooling we use for EMI gaskets.

Which Types of EMI Gasket Materials are Available?

SSP fabricates your EMI gasket from shielding silicones and fluorosilicones in the following types.

  • MIL-DTL-83528 QPL Certified
  • Corrosion Resistant
  • Low Shore A/Soft
  • Fuel & Solvent Resistant
  • Low Outgassing (ASTM E595)
  • Most Electrically Conductive
  • Flame Retardant (UL 94V-0)
  • Reinforced
  • Most Cost Effective
  • Non-Silicone Based

What are MIL-DTL-83528 QPL Certified EMI Gaskets?

MIL-DTL-83528 QPL Certified EMI gaskets meet the requirements of MIL-DTL-83528 and are part of the Qualified Products List (QPL) for this specification. MIL-DTL-83528 (MIL-G-83528) is a U.S. military specification that defines conductive elastomer types and shielding effectiveness levels. Materials on the M83528 QPL meet all MIL-DTL-83528 requirements and have been tested by the Defense Logistics Agency (DLA), which is part of the U.S. Department of Defense (DoD).

What are M83528 Part Numbers (Slash Sizes)?

M83528 part numbers are fabricated from materials that meet the requirements of the  MIL-DTL-83528 specification. They are divided into numeric types that are preceded by a slash (/). That’s why these part number designations are also called slash sizes.  

Use the table below to find M83528 part numbers.

Specification Sheet

Short Description

Long Description

M83528/001

Solid Cord (Circular Strip)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Circular Strip, .040 Through .250 Diameter.

M83528/002

Standard EMI O-Rings

Gasketing Material, Conductive, Shielding Gasket, Electrical, O-Ring, Standard.

M83528/003

Solid D (Solid D Strip)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Solid “D” Shaped Strip.

M83528/004

EMI Connector Gaskets (Flange Mount Connectors)

Gasketing Material, Conductive, Shielding Gasket, Electronic, EMI/RFI, Connector Flange Mount.

M83528/005

Non-Standard EMI O-Ring

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, O-Ring, Non-Standard.

M83528/006

Rectangular D

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Rectangular, D-Cross Section.

M83528/007

Hollow D Strip

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow D-Strip.

M83528/008

Hollow P Strip

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow P-Strip.

M83528/009

Solid Rectangle Strip

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Solid Rectangular Strips.

M83528/010

Solid U Channel (Channel Strip)

Gasketing Material, Conductive, Elastomer, Electrical, EMI/RFI, Channel Strip.

M83528/011

Hollow Tube (Hollow O Strip)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, Hollow O-Strip.

M83528/012

Flat EMI Waveguide Gaskets (Flat Circular Washers)

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, Electrical, EMI/RFI, Flat Circular Washer.

M83528/013

Round EMI Waveguide Gaskets

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, Electrical, EMI/RFI, Waveguide.

M83528/014

Time Totalizing Meter

Gasketing Material, Conductive, Shielding Gasket, Electronic, Elastomer, EMI/RFI, for Use in Time Totalizing Meters Covered by MIL-M-7793.

Which M83528 EMI Gasket Material Do You Need?

MIL-DTL-83528 is divided into lettered sections. SSP makes MIL-DTL-83528 QPL certified EMI gasket materials that meet the requirements of A, B, C, D, and K, as shown in the table below. 

Type

Base Elastomer

Filler

Typical Applications

Key Strengths

A

Silicone

Silver-Copper

Aerospace enclosures

High shielding effectiveness

B

Silicone

Silver-Copper

Military electronics

Good balance of shielding and other properties 

C

Fluorosilicone

Silver-Copper

Jet fuel environments

High shielding effectiveness

D

Fluorosilicone

Silver-Aluminum

Harsh aerospace environments

Good balance of shielding and other properties 

K

Silicone

Silver-Copper

Commercial/industrial

High shielding effectiveness

Which MIL-DTL-83528 EMI Gasket Materials are Available?

Click the images or links below to learn more about SSP’s MIL-DTL-83528 Type A, B, C, D, and K materials.

What are Corrosion Resistant EMI Gaskets?

Corrosion resistant EMI gaskets resist galvanic corrosion, which occurs two dissimilar metals are in contact with each other in the presence of an electrolyte (like water or salt solution) and an electrical current flows between them, causing one metal to corrode preferentially.

SSP’s corrosion resistant EMI gasket materials are shown below. These nickel-aluminum-filled silicones are a cost-effective alternative to silver-filled EMI shielding gaskets. SSP2529 is an offset to CHO-SEAL 6502 and SSP2551 is an offset to CHO-SEAL 6503.

Corrosion resistant EMI gaskets are used in environments where enclosures require EMI shielding and are exposed to harsh environments with moisture, salt, chemicals, or temperature extremes. Other gasket materials can rapidly degrade, but corrosion resistant EMI gaskets maintain sealing and shielding over time. They are used in these and other applications.

  • Naval and Marine Equipment: radar systems, communications consoles, and watertight enclosures
  • Military Ground Vehicles: enclosures for electronics in tanks, armored vehicles, and field-deployed control systems
  • Aerospace Systems: external aircraft electronics, connectors, and sealed avionics housings
  • Outdoor Telecommunications Equipment: control panels, monitoring systems, and instrument enclosures
  • Medical Devices in Harsh Cleaning Environments: MRI shielding rooms, portable diagnostic devices, and surgical enclosures 
  • Rail and Mass Transit Systems: signal control boxes, communications enclosures, and power converters

White Paper: Corrosion Resistant EMI Gaskets

Nickel-aluminum-filled silicones exhibit the lowest amount of flange pitting from galvanic corrosion, an electrochemical process that occurs when two different metals are in contact in a saltwater environment. These shielding silicones also exhibit excellent galvanic stability with aluminum flanges.

What are Soft EMI Gaskets?

Soft EMI gaskets are made of shielding silicones with durometers as low as 30 Shore A. They provide reliable sealing under low closure force.

Like other types of elastomeric gaskets, a soft EMI shielding gasket is compressed by a percentage of its size. This compression forms a seal that physically fills the gap between two surfaces. When the compressive stresses are removed, the EMI gasket is supposed to return to its original thickness. If it does not, this irrevocable deformation (compression set) can leave a gap and cause seal failure.

Note: Harder materials with higher durometers are more difficult to compress, but electrically conductive silicones are not excessively hard because of the addition of particles. In fact, EMI silicones are available in a range of hardnesses, including lower durometers for gaskets where there is less closure force.

Soft EMI gasket materials from SSP include SSP502-30, a nickel-graphite shielding silicone that is comparable to CHO-SEAL S6305, 6330, 6370, 6371, 6372, and 6308. Also filled with nickel-graphite is SSP502-40 silicone, an offset to CHO-SEAL S6305, 6330, 6370, 6371, 6372, and 6308.

Other soft EMI gasket materials are available as well.  SSP502-40-V0 is a soft, nickel-graphite silicone that is an offset to GORE GS2100 and provides UL 94V0 flame resistance. SSP550-45 is a soft, silver-aluminum fluorosilicone with ASTM E595 low outgassing that is comparable to CHO-SEAL 1287 and 1298.

What are Fuel and Solvent Resistant EMI Gaskets?

Fuel resistant EMI gaskets are made of fluorosilicones. They are used in military and civilian applications that require resistance to harsh chemicals, including fuels and solvents.

Fuel and solvent resistant EMI gaskets can be fabricated from a QPL certified MIL-DTL-83528, Type D elastomer and nickel-graphite materials in 50, 60, and 80 durometer (Shore A).

SSP also offers two two silver-aluminum fluorosilicones, including a passivated product. Passivation increases the corrosion resistance of the electrically conductive metal particles.

White Paper: Fluorosilicones for Environmental Sealing and EMI Shielding

Fluorosilicones combine the high and low-temperature resistance of silicones with the fuel and oil resistance of fluorocarbons. Compounds that are filled with metal or metal-coated particles also provide electrical conductivity and EMI shielding.

What are Low Outgassing EMI Gaskets?  

Low outgassing EMI gaskets are made of shielding elastomers that meet ASTM E595 requirements for low levels of silicone outgassing, or offgassing, that can occur in vacuum environments like outer space. ASTM E595 is a standard test method that determines total mass loss (TML) and collected volatile condensable materials (CVCM).

Low outgassing EMI gaskets are used in satellite communications, typically as gaskets for optics, sensors, and electronics that could cloud from silicone outgassing in the vacuum environment of space.  

SSP’s low outgassing EMI materials include a QPL certified MIL-DTL-83528, Type B offset to CHO-SEAL 1285 and an offset to CHO-SEAL 6502. Low-outgassing flame retardant offsets to GORE GS2100 and GORE GS5200 are also available. In addition, SSP makes shielding gaskets from an EMI silicone for extreme low temperature environments and a silver-aluminum fluorosilicone.

What are the Most Electrically Conductive EMI Gaskets?

The most electrically conductive EMI gaskets have silver-coated particles. Silver is the best electrical conductor because its valence electron is loosely bound and moves easily with very little resistance through the metal’s crystal structure.  

SSP’s most electrically conductive EMI gaskets can be made two MIL-DTL-83528 QPL certified EMI silicones that are filled with silver-copper.

There are also three other SSP materials for the most electrically conductive EMI gaskets.

  • SSP2476-65 is a silver-aluminum shielding silicone for optimized surface conductivity. 
  • SSP482-75 is a silver-nickel shielding silicone that meets MIL-DTL-83528, Type L requirements.
  • SSP482F-75 is a silver-nickel fluorosilicone for harsh environments.

White Paper: How to Choose Particle-Filled Silicones to Meet Multiple Design Requirements

The EMI shielding that’s used in automotive, aerospace, and medical electronics must meet multiple design requirements. For example, an EMI gasket that’s used with aircraft may need to resist the splash of jet fuel. Shielding that’s used with EV charging stations may require compliance with UL 94 standards for flammability. 

What are Flame Retardant EMI Gaskets (UL-94V0)?

Flame-retardant EMI gaskets materials are made of shielding silicones with a UL 94 V0 flame rating. They contain nickel-graphite particles and meet ASTM E595 requirements for low levels of outgassing. Applications include wireless infrastructure equipment, telecommunications equipment, portable electronic devices, microwave equipment, high frequency cable connectors, military programs and spaceflight. 

Use SSP’s flame rated EMI shielding materials instead of GS2100 or GS5200 from W.L. GORE, which discontinued these popular GORE-SHIELD® materials in 2020.

What are Reinforced EMI Gaskets?

Reinforced EMI gaskets contain nickel-graphite particles and are reinforced with an inner layer of conductive fabric. They are fabricated from sheet or rolls materials that come in four different inch-based thicknesses: .020, .024, .032, .040, and .062. 

Reinforced EMI gaskets are used in applications where there is a risk of tearing. The conductive fabric layer enhances electrical conductivity and provides mechanical strength and flexibility. They are used in these and other applications.

  • Telecommunications Equipment: base stations, routers, and network switches where frequent maintenance or vibration occurs
  • Military and Aerospace Systems: enclosures, control panels, and cockpit electronics 
  • Medical Devices: MRI machines, infusion pumps, and diagnostic equipment
  • Consumer Electronics: laptops, smartphone, and gaming consoles that need reinforcement to maintain form and function over many open and close cycles
  • Automotive Electronics: ADAS, infotainment systems, and electronic powertrain modules 
  • Industrial Control Systems: PLCs, HMIs, and SCADA equipment, especially in high-vibration or dirty environments 
  • Data Centers: Server racks, cabinets, and access doors


SSP offers two composite materials, both of which have physical properties that are superior to non-reinforced elastomers.

What are the Most Cost Effective EMI Gaskets?

The most cost effective EMI gaskets are made from a nickel-graphite EMI silicone. Theys are suitable for applications where cost is a key consideration. Examples include low-cost electronics such as some mobile devices.

SSP’s most-cost effective EMI shielding silicone, SSP502-65, supports thinner, smaller, and lighter weight designs. It’s also an offset to CHO-SEAL 6305.  This 65-durometer nickel-graphite EMI elastomer offers performance levels that are comparable to shielding silicones with silver-coated particles. Independent test results for salt spray according to ASTM B117 are also available.

What are Non-Silicone EMI Gaskets?

Non-silicone EMI gaskets are made from a 75-durometer nickel-coated EPDM shielding elastomer. They are used in applications that require silicone-free products with low outgassing. Examples include clean or optical environments and production facilities that do not allow silicones to minimize the risk of surface defects in coatings, paints, or adhesives. 

SSP2514-75 EMI gasket material provides excellent ozone and UV resistance along with good compression set and solvent resistance. As with all SSP’s EMI shielding elastomers, customized versions are available in different durometers.

White Paper: Frame Gaskets for EMI Shielding – How Molding Reduces Costs, Increases Yields, and Supports Low-Volume Production

SSP supplies mold-able EMI silicones. For frame gaskets, molding minimizes material waste, maximizes material yields, and eliminates the need to bond cut lengths. Fabrication processes like die cutting are efficient, but the cut-out section of a frame gasket can represent significant material waste. 

Video: EMI Gasket Applications

White Paper: EMI Shielding for Electric Vehicles

By their very nature, EVs place a large amount of electrical and electronic content into confined spaces. The radiated and conducted emissions from these systems can disrupt circuits and result in conditions that range from minor inconveniences to dangerous losses of vehicle function. There are sources of EMI outside of the vehicle as well.  

FAQs about EMI Gaskets

Q1: What is MIL-DTL-83528?

Answer: MIL-DTL-83528 is a U.S. military specification that defines performance requirements for conductive elastomer EMI gaskets. It specifies shielding effectiveness, filler types, environmental resistance, and compliance testing. SSP’s QPL-listed EMI gaskets meet these standards for aerospace, defense, and other high-reliability applications.

Q2: What materials are used in EMI gaskets?

Answer: EMI gaskets are typically made from conductive silicone or fluorosilicone elastomers filled with conductive particles such as silver-aluminum, silver-copper, or nickel-graphite. The choice of material depends on environmental exposure, required shielding level, and cost considerations.

Q3: How much shielding effectiveness can EMI gaskets provide?

Answer: SSP’s MIL-DTL-83528 EMI gaskets deliver shielding effectiveness up to 110 dB at 10 GHz, depending on the filler and base elastomer. Performance varies by gasket type and installation method.

Q4: What industries use EMI gaskets?

Answer: EMI gaskets are essential in aerospace, defense, medical devices, telecommunications, and industrial equipment. They are used anywhere EMI shielding and environmental sealing are required.

Q5: Can EMI gaskets also provide environmental sealing?

Answer: Yes. Conductive elastomer EMI gaskets provide both EMI/RFI shielding and environmental sealing against dust, moisture, and contaminants. Fluorosilicone grades also resist fuels, solvents, and aggressive chemicals.