EMI Shielding Materials

Comprehensive Shielding Solutions for Research & Industrial Applications from Eata Electronic

Figure 1: EMI shielding gasket installed along the flange of an electronic enclosure

Electromagnetic interference has become one of the most persistent challenges facing modern electronics design. As devices operate at higher frequencies, pack more circuitry into tighter spaces, and communicate through wireless protocols, the risk of unwanted electromagnetic emissions and susceptibility grows accordingly. Effective EMI shielding demands materials that can attenuate, absorb, or redirect electromagnetic energy across the full spectrum from kilohertz to gigahertz. Whether your project involves shielding a sensitive medical instrument from external noise, containing emissions from a high-speed processor, or protecting telecommunications infrastructure, the selection of appropriate shielding materials determines whether your device passes regulatory testing and performs reliably in real-world environments.

Eata Electronic supplies a broad range of shielding materials engineered to address virtually every EMI control requirement encountered in research laboratories and industrial production. Our portfolio encompasses conductive elastomer gaskets, fabric-over-foam seals, knitted wire mesh, conductive fabric tapes, metal foil laminates, sprayable conductive coatings, and high-permeability magnetic shielding alloys. Each material category offers multiple formulations, profiles, and performance grades to match specific frequency ranges, environmental conditions, compression forces, and budget constraints. Our materials team works directly with customers to identify the optimal shielding approach for each unique application.

Figure 2: Conductive silicone gasket under compression between aluminum test plates

EMI Shielding Gaskets

EMI shielding gaskets represent the most widely deployed category of shielding materials, providing electrical continuity across mechanical seams, doors, panels, and access points in electronic enclosures. These gaskets fill gaps between mating surfaces, maintaining a low-impedance path that prevents electromagnetic energy from leaking through enclosure discontinuities. Eata Electronic supplies several gasket construction types, each suited to particular mechanical, environmental, and electrical requirements.

Fabric-Over-Foam (FOF) Gaskets

Fabric-over-foam gaskets combine a compressible polyurethane or neoprene foam core with an outer layer of nickel-copper or nickel-plated conductive fabric. This construction delivers excellent shielding effectiveness up to 102 dB at 100 MHz across a wide frequency range, while requiring relatively low compression force. The foam core provides consistent spring-back over thousands of compression cycles, and the conductive fabric ensures reliable electrical contact even on lightly loaded flange designs. Available in rectangular, D-shaped, C-fold, P-profile, and custom cross-sections, FOF gaskets are ideal for consumer electronics, telecommunications equipment, medical devices, and automotive control modules where low closure force and cost efficiency are priorities.

Conductive Elastomer Gaskets

Conductive elastomer gaskets are manufactured from silicone or fluorosilicone rubber loaded with conductive filler particles, typically silver-plated aluminum, silver-plated copper, nickel-graphite, or silver-plated glass. These solid rubber gaskets provide both EMI shielding and environmental sealing against moisture, dust, and chemical exposure. Shielding effectiveness reaches 120 dB at 10 GHz depending on filler type and compression. Silver-aluminum filled silicone meets MIL-DTL-83528 Type B requirements and offers the best balance of conductivity, corrosion resistance, and cost for aerospace and defense applications. Nickel-graphite filled variants provide strong commercial-grade performance at significantly lower cost, achieving 60 dB from 30 MHz to 10 GHz. Operating temperature spans from minus 60 to plus 185 degrees Celsius, with certain grades tolerating up to 220 degrees Celsius.

Knitted Wire Mesh Gaskets

Knitted wire mesh gaskets are produced from metal wires including Monel, tin-plated copper-clad steel, aluminum, and stainless steel, knitted into a tubular or flat configuration. These gaskets excel in demanding environments where mechanical durability, high-temperature tolerance, and broadband shielding performance are required. Shielding effectiveness typically exceeds 100 dB across 10 MHz to 1 GHz. When combined with an elastomer core, knitted mesh gaskets provide dual-function EMI and environmental sealing suitable for military shelters, industrial control cabinets, and aerospace enclosures.

Conductive Foam Gaskets

Electrically conductive foam gaskets consist of open-cell polyurethane foam impregnated with conductive material throughout the matrix. These lightweight, highly conformable gaskets are well suited for compact electronic assemblies, I/O panel shielding, and connector gasketing where space is limited and low compression force is essential. Available with or without conductive pressure-sensitive adhesive backing, conductive foam provides shielding effectiveness exceeding 103 dB at 100 MHz. The material can be die-cut into complex shapes, kiss-cut on rolls for automated assembly, or supplied in continuous sheet form.

EMI Gasket Material Comparison

Figure 3: Roll of nickel-copper plated conductive fabric tape with conductive adhesive backing

Conductive Fabric Tapes and Metal Foil Laminates

Conductive tapes provide a versatile, easy-to-apply shielding solution for cable wrapping, seam sealing, grounding, and component-level shielding where rigid gaskets cannot be installed. These materials bridge the gap between flexible textile processing and electrical conductivity.

Conductive Fabric Shielding Tape

Our conductive fabric tape is constructed from polyester substrate electroplated with nickel followed by copper and a protective nickel overlayer, creating a metal-textile composite with excellent surface conductivity and electromagnetic shielding from 100 kHz to 3 GHz. The conductive fabric is laminated with a conductive pressure-sensitive acrylic adhesive that maintains electrical continuity through the Z-axis between the tape and the substrate. Sheet resistivity below 0.03 ohms per square and shielding effectiveness of 70 dB at 100 MHz, 80 dB at 1 GHz, and 90 dB at 3 GHz make this tape suitable for notebook computer cable shielding, LCD cable wrapping, laboratory test fixture shielding, and lightweight electronic grounding. Available in standard widths from 10 mm to 100 mm, with custom die-cut configurations supported.

Copper and Aluminum Foil Tapes

Solid metal foil tapes offer the highest electrical conductivity among tape solutions. Copper foil tape with conductive adhesive provides exceptional shielding for RF cable wraps, transformer winding termination, and electrostatic discharge grounding. Aluminum foil tape offers a lighter, more economical alternative for general-purpose EMI shielding and moisture barrier applications. Both materials are available with standard or flame-retardant adhesive systems and can be supplied in rolls or pre-cut shapes.

Conductive Coatings and Paints

When enclosure redesign is impractical or when shielding must be applied to complex internal geometries, conductive coatings offer an effective sprayable, brushable, or dip-coatable solution. These coatings convert electrically insulating surfaces into conductive shields that attenuate electromagnetic emissions.

Silver-Filled Conductive Coating

Silver-filled acrylic or epoxy coatings provide the highest shielding effectiveness among sprayable materials, achieving 60 to 80 dB across 30 MHz to 1.5 GHz. The silver flake content ensures excellent surface conductivity below 0.1 ohm per square. These coatings adhere strongly to ABS, polycarbonate, nylon, PVC, and other common plastics used for electronic housings. No heat curing is required for acrylic versions, simplifying production integration.

Silver-Coated Copper Conductive Paint

Silver-coated copper conductive paint delivers near-silver shielding performance at substantially lower material cost. The acrylic lacquer base pigmented with highly conductive silver-coated copper flake produces a smooth, hard, abrasion-resistant finish suitable for high-volume plastic enclosure production. This one-part, solvent-based system is ready to spray with no let-down necessary, adheres strongly to most injection-molded plastics, and provides effective EMI/RFI shielding across a broad frequency range. Available in liquid and aerosol formats.

Nickel and Carbon Conductive Coatings

Nickel-filled coatings provide a corrosion-resistant, broadband shielding option at moderate cost, suitable for industrial and commercial electronics where extreme conductivity is not required. Carbon-filled conductive paints offer an economical entry-level solution for ESD protection and low-frequency EMI control on wood, drywall, and other porous substrates.

Figure 4: Automated spray system applying copper conductive coating to interior of plastic electronic enclosure

Magnetic Shielding Materials

While the majority of EMI shielding materials address electric field and plane-wave radiation through conductivity-based reflection, low-frequency magnetic fields require a fundamentally different approach. Magnetic shielding relies on high-permeability materials that redirect magnetic flux lines away from sensitive regions rather than reflecting electromagnetic energy.

Mu-Metal and Permalloy Shielding

Mu-metal, also known as Permalloy C or HyMu 80, is a nickel-iron-copper-molybdenum soft magnetic alloy with initial permeability of 30,000 to 60,000 and maximum permeability exceeding 150,000, among the highest values achievable in any commercial material. This extraordinary permeability enables mu-metal to attenuate low-frequency magnetic fields from DC to several kilohertz with shielding factors exceeding 65 dB in properly designed cylindrical configurations. The alloy saturates at approximately 0.8 T, making it ideal for shielding small, sensitive instruments against Earth field variations, power line interference, and stray fields from transformers and motors. Available as sheet, foil, strip, wire, and precision-formed shields.

1J85 Permalloy

1J85 permalloy, conforming to Chinese GB/T standards with approximately 80% nickel and 20% iron content, delivers initial permeability above 80,000 and near-zero magnetostriction. This material is extensively used in precision instrumentation including fluxgate magnetometers, atomic clocks, MRI room shielding, geophysical survey equipment, and cold-atom physics research where nanotesla-level field stability is required. The alloy can be supplied in rod, plate, strip, and custom-fabricated shield configurations, with hydrogen annealing available to optimize magnetic performance after forming.

Low-Carbon Steel Magnetic Shields

For applications involving stronger magnetic fields where high-permeability alloys would saturate, low-carbon steel such as AISI 1008/1010 provides a cost-effective alternative. With saturation flux density of 2.2 T compared to 0.8 T for mu-metal, steel shields tolerate substantially higher incident fields while delivering moderate shielding effectiveness of 34 to 40 dB. Steel is also structurally robust, widely available, and easily fabricated into shields, enclosures, and barrier panels.

Figure 5: Curved mu-metal magnetic shielding sheet demonstrating material flexibility and surface finish

Board-Level Shielding Solutions

Board-level shielding represents the most cost-effective approach to EMI control when the interference source or victim is localized on a printed circuit board. Metal can shields soldered directly to ground traces isolate noisy components such as processors, oscillators, and power regulators from sensitive analog or RF circuits on the same board.

• One-piece stamped shields — Economical, high-volume production for permanent installations where post-assembly access is not required
• Two-piece shield systems — Consisting of a fence frame soldered to the board and a removable lid, enabling rework and inspection without desoldering
• Perforated shields — With precisely patterned apertures that allow thermal airflow while maintaining shielding effectiveness above 80 dB
• Custom deep-drawn shields — For applications requiring complex geometries, tall sidewalls, or integrated mounting features

Board-level shields are typically manufactured from tin-plated steel, nickel silver, or stainless steel in thicknesses from 0.15 to 0.5 mm. The shielding effectiveness depends on aperture size, material conductivity, and grounding quality, with properly designed cans achieving greater than 100 dB attenuation at frequencies above 1 GHz.

Shielding Material Selection Reference

Custom Material Development and Fabrication

Beyond our standard catalog of shielding materials, Eata Electronic provides custom engineering services for applications requiring specialized geometries, unique material formulations, or application-specific performance optimization. Our fabrication capabilities include precision die-cutting, CNC slitting, waterjet cutting, laser machining, conductive adhesive lamination, and custom profile extrusion.

For gasket applications, we can develop custom cross-sectional profiles, integrate mounting clips or adhesive backing, specify alternative elastomer bases such as fluorosilicone for fuel resistance or EPDM for outdoor durability, and adjust filler loading to meet specific conductivity or hardness targets. For magnetic shielding, we offer hydrogen annealing services, multi-layer shield design consulting, and precision-formed cylindrical or box shields fabricated to customer drawings. For coating applications, we can recommend application equipment, surface preparation protocols, and curing parameters optimized for specific substrates and production environments.

Our engineering team welcomes inquiries from research institutions and industrial development programs seeking shielding solutions for novel applications. Whether you need a prototype batch of custom-shaped gaskets, a small quantity of annealed mu-metal shields for a physics experiment, or formulation guidance for coating an unconventional substrate, we can evaluate your requirements and propose practical material solutions.

For Research or Industrial Raw Materials, Not For Personal Medical Use!