Electrically conductive epoxies are adhesive compounds that integrate the bonding capabilities and other properties of epoxy resins with electrical conductivity. Electrically conductive adhesives (ECAs) are formulated to provide reliable electrical pathways while ensuring effective adhesion to various substrates. These qualities render ECAs highly suitable for multiple aerospace, automotive, medical, telecom, and consumer device applications. Conductive epoxies offer a clean, lead-free solder alternative for component attachment in many electronic applications where the bonded components are temperature sensitive.
This article aims to help you understand conductive epoxies, covering their types, benefits, and applications.
Composition of Conductive Epoxies
A conductive epoxy resin system consists of epoxy resin mixed with a conductive filler. The epoxy resin provides the adhesive and mechanical strength properties to the design, and the conductive filler contributes electrical conductivity. There are a variety of conductive fillers of different sizes, shapes, and types, including metallic particles (such as silver, copper, or nickel) or non-metallic particles (such as carbon or graphite).
Why Should You Use a Conductive Epoxy?
Electrically conductive epoxy performs two key functions. It can mechanically bond two surfaces (substrates) with robust bonding strength and form an electrical interconnection between the two bonded substrates. Various formulations of epoxy resin systems can improve strength and conductivity and offer properties such as low thermal expansion, high thermal conductivity, and heat resistance.
Types of Conductive Epoxies
Several conductive epoxies are available, each with unique properties and suitable for particular applications. Understanding the following types can help you choose the most suitable one for your application. It is important to consult product technical datasheets and consider compatibility with the intended substrates in selecting a product for a particular application. Specific properties and performance of conductive epoxy resin systems vary depending on the conductive filler used in the design, the filler particle size, shape, and concentration, and other factors.
Silver-Filled Conductive Epoxies
Silver (Ag) is highly conductive, making epoxies with a silver filler ideal for applications that require excellent electrical conductivity. Silver-filled epoxies also offer strong and durable adhesion to various substrates, including metals, ceramics, plastics, and glass, with reliable bonding. They exhibit good thermal conductivity and are corrosion-resistant.
Nickel-Filled Conductive Epoxies
Nickel-filled conductive epoxy systems provide a balance between cost and performance. Nickel (Ni) is a highly conductive material and provides reliable electric conduction yet is more cost-effective than metals such as silver or copper. Nickel-filled conductive epoxy has corrosion-resistant qualities, high strength and durability, relatively good thermal conductivity, and strong adhesion to various substrates, such as metals, ceramics, plastics, and glass.
Copper-Filled Conductive Epoxies
Copper (Cu) imparts excellent electrical conductivity as it is one of the most conductive metals. These epoxies contain copper particles, offering high electrical and thermal conductivity. Copper balances performance and cost, as it is more cost-effective than metals such as silver. Copper-filled conductive epoxy is an excellent thermal conductor with high strength and durability, is inherently corrosion- resistant, and exhibits strong adhesion with reliable bonding. They suit applications requiring high electrical conductivity, resistance to corrosion, and efficient heat dissipation.
Aluminum-Filled Conductive Epoxies
Aluminum (Al) filler provides moderate electrical conductivity and good thermal conductivity, and is often used when weight reduction is a concern.
Graphite-Filled Conductive Epoxies
Graphite is an excellent conductor of electricity. It can withstand mechanical stresses, thermal cycling, and vibration to ensure long-term reliability. Graphite has natural lubricating properties. Adding graphite to an epoxy system improves wear resistance and reduces friction properties. Graphite is a lightweight material and can be used to reduce the overall weight of a product. Graphite-based conductive epoxies are often used in applications requiring lubricity, such as sliding or rotating electrical contacts or coating components that experience friction.
Carbon-Filled Conductive Epoxies
Carbon-filled epoxies strike a balance between electrical conductivity and cost-effectiveness. Carbon particles, such as carbon black, have excellent electrical conductivity. They are commonly used in applications that don’t require extremely high conductivity but still need reliable electrical paths. They are lightweight compared to conductive epoxy with metallic particles, possess good thermal conductivity, and are inherently corrosion-resistant. They are more cost-effective than conductive materials such as silver.
Benefits of Conductive Epoxies
Conductive epoxies offer the following advantages, making them sought-after across diverse industries and applications:
Electrical Conductivity
The top quality of conductive epoxy resin is its ability to conduct electricity. Conductive epoxies act as efficient pathways for electrical signals, ensuring smooth and uninterrupted transmission. This characteristic is crucial in applications with vital electrical connections, such as electronic circuits or sensitive components. Electrical conductivity varies depending on the type and concentration of the conductive filler used in the system. A higher proportion of conductive filler results in higher conductivity but may weaken the bond strength by displacing the adhesive.
Strong Adhesion
Conductive epoxies excel in their adhesion properties, exhibiting excellent adhesion to a wide range of substrates. Whether metals, ceramics, plastics, or glass, they create secure connections that withstand various environmental factors.
Efficient Heat Dissipation
Conductive epoxies help prevent overheating and ensure optimal performance by efficiently dissipating heat generated by electronic components. This is particularly beneficial in high-power applications or devices with critical thermal management.
Mechanical Strength
Conductive epoxies offer excellent mechanical strength with their ability to withstand various stresses, including mechanical loads and thermal cycling.
Chemical Resistance
Conductive epoxies offer impressive resistance to chemicals, solvents, and environmental factors, safeguarding bonded components in harsh environments or against corrosive substances. This chemical resilience ensures the longevity and functionality of the epoxy’s electrical and adhesive properties, even in challenging conditions.
Thermal Stability
Many conductive epoxies exhibit good thermal stability and tolerate high temperatures without significant degradation. Conductive epoxies offer efficient thermal dissipation, thereby improving the reliability of electronic systems by cooling the component.
Versatility
Conductive epoxies can be tailored to deliver optimal application performance through formulation adjustments and targeted selection of conductive fillers.
Durability
The durability of conductive epoxy resin ensures long-term performance and reliability, reducing the need for frequent repairs or replacements. As a result, industries can rely on the enduring properties of conductive epoxies in applications where consistent and sustained performance is vital.
Ease of Application
The user-friendly nature of epoxy resin systems streamlines manufacturing and assembly processes, saving time and increasing productivity. As a result, smoother operations and faster turnaround times are enjoyed with the efficient application of conductive epoxies.
Common Applications of Conductive Epoxies
Here are some common applications where conductive epoxies are employed:
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Electronics:
electronic component assembly, such as electrical bonding components (e.g., electronic chips and printed circuit boards), die attach processes and solderless interconnections, wire bonding, component renovation, display interconnections, and heat dissipation
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Aerospace and defense:
enclosures, gaskets, and seals to provide electromagnetic interference (EMI) or radio-frequency shielding, grounding, and conductive sealing (e.g., aircraft electronics)
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Automotive:
bonding sensors (e.g., for engine management systems), electronic control units, electrical grounding applications, cameras, ADAs, radars, and LiDARs
- Medical devices: medical electronics, electrode fabrication, and implantable device production (e.g., pacemakers)
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Energy and renewable sources:
assembling fuel cells, solar panels, sensors, and batteries (e.g., for renewable energy systems or electrochemical applications)
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Telecommunications:
bonding antennas, connectors, and electronic modules (e.g., for wireless communication devices)
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Consumer electronics:
bonding touchscreens, display assemblies, and PCBs (e.g., for smartphones, tablets)
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Industrial equipment:
bonding electronic modules, sensors, and control systems (e.g., for manufacturing machinery)
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Research and development:
prototyping, circuit design, and experimental setups (e.g., in laboratories)
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Wearable Technology:
bonding flexible electronics, sensors, and smart textiles (e.g., fitness trackers, smartwatches)
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Robotics:
electrical connections, and circuit board assembly (e.g., for robotic arms, drones)
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Optoelectronics:
bonding LEDs, optical sensors, and fiber optics (e.g., for lighting systems, visual communications)
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Instrumentation:
bonding sensors, control systems, and data acquisition devices (e.g., for scientific instruments)
United Resin: Powering Connectivity With Superior Conductive Epoxies
United Resin has your solution for superior conductive epoxy resin. We have a legacy of over 50 years of experience with epoxy resin systems and have consistently met our valued customers’ epoxy resin needs. Our unwavering commitment is to excellence and quality.
United Resin’s conductive epoxy resin systems include the following featured products:
United Resin Conductive Epoxy with Hardener 601
Our most popular system, with very low resistivity and good lap shear strength. Approved and listed under NSN 8040-01-518-7921.
United Resin Silver-filled Epoxy with Hardener 601
Military-grade material meets Mil-Spec MMM-A-1931 TYPE II.
United Resin NCE Paste Adhesive with Hardener 205
For those electrically conductive applications exposed to salt water. Approved and listed under NSN 8040-01-231-2399.
United Resin Conductive Epoxy with Hardener 143
Designed to make electrical connections where soldering is impractical and for RF shielding applications. Approved and listed under NSN 8040-00-450-7259.
All United Resin epoxy systems are non-hazardous and REACH/RoHS compliant.
Contact us today to explore our high-quality epoxy resin systems, including conductive epoxy resin systems. You can also request a quote to get started.
The information presented in this blog is intended for general background and informational purposes only and not as advice about any product, application, or process. We encourage you to contact us for information concerning your specific needs and requirements and to discover how United Resin may assist you.