With the layout of naval vessels, controlling electromagnetic interference (EMI) is a must to maintain operations. Consider all the systems operating within a single vessel, including radar (search, navigation), satellite communications (SATCOM), radios operating at multiple frequency bands (HF, UHF, VHF) and systems for electronic warfare. With all these instruments operating within proximity, there is a strong likelihood of EMI between neighbouring systems with overlapping frequencies.   

EMI Aboard Naval Vessels Compromises Systems Performance and Stealth

In the simplest context, EMI is the transmission of frequencies between neighbouring devices where unwanted signals from one device are picked up by the other. These unwanted signals can disrupt the device receiving the signals resulting in disruption or malfunction. Aboard naval vessels, EMI can cause several critical systems to fail, compromising the entire operation.

Specifically, EMI reduces both the range and resolution with radar systems. With radio systems, EMI causes crosstalk, hampering communication efforts. Stray frequencies not properly contained also increase the electromagnetic signature of the vessel, which jeopardizes the stealth of the ship, increasing visibility to combatants.

Any shortcomings from shielding EMI will lead to downtime as crews must be dispatched to work on repairs. Higher overall maintenance and operations costs are a downstream consequence of improper or incomplete shielding. Amongst the many materials that protect a vessel from EMI are electrically conductive coatings which are particularly useful for tight spaces and retrofitting.    

Electrically Conductive Coatings Shield Critical Naval Equipment

A well-known method for shielding and containing EMI is to surround equipment with electrically conductive material. You essentially put the device in a Faraday cage which attenuates any signals generated. There are two main mechanisms that a conductor achieves attenuation: reflection and absorption. 

Many assemblies aboard naval vessels are composed of plastic and composite materials which have advantages over metals; namely they help lightweight the ship for less drag and resist corrosion from saltwater exposure. The shortcoming of these materials is their transparency to EMI, meaning the parts must be metallized to contain EMI.

Electrically conductive coatings are an easy way to metallize insulating materials like plastics so they can effectively shield internal devices from EMI. Coatings are highly durable, engineered to last many years and can conform to the intricate geometries of structures like radar housing. 

MG Chemicals’ Electrically Conductive Coatings for Naval Vessels

MG chemicals boast a full line of electrically conductive coatings that effectively shield EMI. This line contains different binder systems suited for different environments and substrate types. More specifically, the AR series are designed for interior environments, especially plastic housing, materials increasingly used for radar circuits. Applying conductive coatings to parts of the interior radar housing unit helps to block external RF, mitigating problems like radar ghosting. 

Complimentary to the AR series are the water-based conductive coatings (WBU series). These coatings have similar performance to the AR series but with the binder dispersed in water, they have little odor, meaning there is little downtime following application. The WBU series also adheres well to a wide variety of substrates like glass, plastics, metal and wood, making it easy to apply around common building materials. The coating can be applied around seams and joints within the ship, preventing gaps where radiation can leak into or out of. 

For spaces that are subjected to harsh chemicals like fuels, hydraulic fluids and cleaners, our ER series coatings have exceptional chemical resistance and can withstand repeated exposure with no loss in performance. These coatings are especially suitable for parts like power distribution housing, pump control enclosures and junction boxes within engine rooms. 

Conductive coatings contain fillers like nickel, silver, silver-coated copper and carbon that govern signal attenuation. It is critical when choosing a conductive coating to know what frequencies must be shielded and what level of attenuation is needed. 

Electrically conductive coatings are a practical, turnkey solution for mitigating issues related to EMI in within high-density structures like naval vessels. These coatings offer a quick method to metallize modern lightweight insulating materials, helping the ship maintain operational readiness while reducing maintenance and downtime.

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MG Chemicals, a CADSI and Ontario Defence Association (ODA) member, manufactures specialty chemicals for electronics and defence applications from its facility in Burlington, Ontario. ​​