What Are Dielectric Coatings and Why Are They Important?

What Is A Dielectric Coating?

A dielectric coating is a thin coating applied to a component’s surface to provide electrical insulation. It is engineered from materials with tightly bound electrons. There are few or no free charge carriers available to conduct current. This lets the coating withstand high electric fields without breaking down. By blocking free electron movement, dielectric coatings prevent shorts, arcing, and electrical shock between conductive surfaces, improving both safety and reliability. The result is extended component life, reduced maintenance, and consistent performance in demanding environments.

Dielectric Strength, Coating Thickness, and Pinholes

Dielectric strength is the maximum electric field an insulating material can withstand before it breaks down and electrical current can flow to the substrate. The higher a coating’s dielectric strength, the greater the voltage it can resist without electrical failure.

Dielectric strength is closely related to coating thickness. In general, thicker coatings can withstand higher voltages because they provide a greater isolating barrier between conductive surfaces. However, increasing coating thickness is not always the best solution, as it can affect part dimensions, functionality, or performance. DECC works closely with customers to determine the optimal coating thickness that meets both performance requirements and dielectric testing standards.

One common cause of dielectric failure is the presence of pinholes or other contamination mixed into the coating. These openings can create potential pathways for electrical current, reducing the coating’s isolating effectiveness. This is where surface preparation is crucial to allowing for the most effective adhesion to the part. To verify that a coated part provides specified electrical insulation, DECC uses high-potential (hipot) testing.

What is Hipot Testing?

Hipot testing (high-potential testing) is used to verify that a dielectric coating provides the required level of electrical isolation. During the test, a specified voltage is applied to the coated component to determine whether the coating can withstand the electrical stress without breaking down or allowing current leakage. The test voltage is typically set higher than the component’s operating voltage to provide an additional margin of safety and ensure reliable performance.

DECC can hipot test up to 100% of parts up to 5 kV to ensure high quality and confirm the integrity of its dielectric coatings. By verifying that coated surfaces remain non-conductive under high-voltage conditions, DECC ensures that components can meet your performance requirements and are protected against electrical shorts, arcing, and insulation failures.

DECC’s Dielectric Coating Application Process

We have a dedicated cell for dielectric coatings with ample capacity, separate from our core coating operations. Dielectric coatings require a high level of precision, not only in coating thickness, but also in the exact areas where the coating is applied. In many applications, certain surfaces must be electrically insulated to prevent current flow, while other areas must remain conductive to ensure the part functions as intended. With these requirements in mind, DECC has developed a proven process that delivers consistent, high-quality results.

The process begins with one of the most important steps: surface preparation. Proper surface preparation is the long-term foundation for strong coating adhesion. DECC utilizes a three-stage alkaline cleaning process consisting of wash, rinse, and dry. Depending on the application and substrate, we also offer additional surface preparation methods to ensure the coating bonds properly and performs as intended.

Once the parts are properly prepared, they move through our automated reciprocating flatline spray system, which can coat parts up to 48 inches wide and virtually unlimited in length. This system delivers precise coating application, making it ideal for both flat and contoured components while supporting high-volume production.

After coating, the parts move through our versatile curing system, which utilizes multiple-spectrum wavelengths to accommodate a variety of dielectric coating materials and curing requirements. Once cured, each part is tested to verify it meets the customer’s specified performance requirements, ensuring the coating delivers the electrical isolation needed for its intended application.

Whether you’re developing a new component or preparing for production, DECC can support your project with small-batch test runs and engineering guidance throughout the process. Our experienced team works closely with customers to help refine coating requirements, validate performance, and move confidently from design to production.

Benefits of DiElectric Coatings

Electrical Insulation: The coatings use dielectric material to stop electrical currents from passing through.

 Electrical Safety: The coating creates a protective barrier preventing electrical breakdown, which can be dangerous to the whole operation.

Enhanced Durability: With the coating acting as a protective layer, it helps the component resist wear, abrasion, and harsh operating environments.

Increased Reliability: Extends component life and reduces the need for maintenance.

Dielectric Coatings DECC APPLIES

Parker Lord® Sipiol UV: Developed specifically for electric vehicle (EV) battery applications. The coating can be applied anywhere electrical insulation is necessary inside a battery pack, such as cooling plates, battery cells, and adjacent components. It cures in seconds when exposed to UV light. Features of this coating include excellent adhesion to different aluminum and metals.

• Electrical Insulation (1 x 10¹¹ ohm-cm)
• Dielectric strength (81–101 kV/mm)
• Dielectric losses
• Thermal conductivity (0.5 W/m·K)
• UL rated

H.B. Fuller® EV Therm 602: A two-component thermally conductive coating that is UV curable. The coating provides good adhesion to various metals and plastics with low viscosity and surface tension to reduce air bubbles. The recommended application for this coating includes heatsinks, cold plates, electronics, and other thermal dissipation applications.

• Electrical insulation (8.9 x 10¹³ ohm-cm)
• Dielectric strength (70 kV/mm)
• Dielectric losses (0.012 dissipation factor at 1 MHz)
• High thermal conductivity (1.0 W/m·K)
• UL rated

Parker Lord®  JMC-700K: Coating provides parts with electrical insulation, heat resistance, and oil resistance. This coating is thermal epoxy, which makes it stand out comparatively to the other listed coatings because it is not UV cured. This coating is intended for aluminum, steel, and motor magnets and is typically used to coat E-motors, cooling plates, and heat sinks.

• Electrical insulation (1.1 x 10¹⁵ ohm-cm)
• Dielectric strength (40–100 kV/mm) – the wide range is due to the desired thickness.
• Low dielectric losses (0.0092 dissipation factor)
• Moderate thermal conductivity (0.52 W/m·K)

Henkel® Bonderite B-DC 5100: Thin coating that provides sufficient electrical isolation without increasing the component weight. This coating is also UV cured, ideal for complex parts such as battery cooling plates, busbars, and housings. Bonderite’s primary substrates are aluminum and copper, but it can be applied to parts that need electrical insulation and thermal management.

• Electrical insulation (1 x 10¹³ ohm-cm)
• Dielectric strength (80 kV/mm)
• Thermal conductivity (0.3-0.4 W/m·K)

Industries Served and Common Applications

While DECC’s current application for dielectric coatings is automotive, battery, and industrial industries, there are other sectors. As the electronic world continues to advance, the need for dielectric coating follows. Get in touch with us today to see if we are able to solve your component problems.

• Automotive: EV battery enclosures, cooling plates, bus bars
• Battery Manufacturing: Battery modules, energy storage systems
• Industrial Manufacturing: Electric motors, generators, robotics, automation equipment
• Medical: Medical devices, imaging equipment, diagnostic electronics
• Alternative Energy: Solar inverters, wind power systems, battery energy storage systems (BESS)

Why You Should Choose DECC

With a dedicated area specifically for dielectric coatings, DECC has a large capacity for coating a high volume of parts from start to finish. We can surface prep, coat, cure, and test parts all in-house, allowing for faster turnaround and increased quality assurance. As every coating application is different, we have the ability to create custom masking and coating designs to suit your specific needs. DECC also has complete traceability throughout every step of the process with our ERP system.