Reliability on the Long Road Ahead | Proven Automotive Conformal Coating Protection that Lasts for Decades

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Mallory McGuinness | September 18, 2020

As an automotive OEM or Tier Supplier, you are consistently challenged by increased safety and regulatory requirements, as well as consumer expectations. Your team is responsible for meeting stringent warranty requirements and packing once-considered “luxury” features into standard vehicles. Consequently, you’re harnessing electronic components to meet pressing demands for safety and comfort.

This industry shift towards reliance on electronics is substantial and will continue indeterminately. In the late 1970s, the cost of electronics comprised around 5% of a vehicle’s total cost, but by 2030, components will comprise 50%. Looking into the future, connected cars responsible for preemptive safety interventions are also emerging. We expect autonomous vehicles to seamlessly travel busy roads without incident through the utilization of lidar, radar, sensors, and other critical components. As we raise the bar on safety requirements, reliability is a critical concept in the self-driving car philosophy.

Therefore, your success is contingent upon reliable electronic systems that incorporate increasing sophistication, density, and complexity. Under the hood, you need to integrate more PCBs with more functionality, and while these components are “smarter,” they are still sensitive to harsh, corrosive environments. To ensure that electronics work flawlessly, new ruggedizing techniques are a requirement.

View our webinar on how to improve automotive electronic performance in harsh service environments.

Don’t Let Harsh Automotive Service Environments Corrode the Value of Your Product

Corrosion is a ubiquitous threat for automotive design engineers and OEMs due to numerous pollutants, liquids, and solids that can erode reliability. Oil, chemicals, and standing water are just a few examples of deleterious environmental variables. Conformal coatings offer good corrosion resistance with a barrier layer, but even at their typical micrometer thinness, space confinements under the hood cause the need for thinner protection.

Parylene conformal coatings satisfy this need with protection as thin as 50 microns, still providing exceptional moisture and chemical resistance and maintaining thermal and dielectric protection through electrical current fluctuations, and ultimately maintaining component performance through adverse automotive environments. And this type of protection will maintain throughout the lifecycle or your product. Parylene lasts for decades.

Each Parylene type has distinct properties due to unique chemical compositions, and you can apply the coating with precise thickness control, so there is a Parylene to answer virtually any need.

For example, in general, Parylene C performs exceptionally well as a barrier to corrosion due to the coating’s ability to minimize the influence of the factors that affect coating lifetime and performance, including the following:

  • Oxygen permeability − low oxygen permeability for a polymer coating  
  • Ionic permeability − salts have a difficult time passing through the coating 
  • Coating porosity − at a thickness of just 5 to 8 microns, Parylene C forms a pinhole/pore-free coating  

Parylene C performs very well in environmental tests known as Salt Fog, Flowers-of-Sulfur (FoS), and Mixed Flowing Gases (MFG), proof of its superior corrosion-resistance properties.  

  • Salt Fog simulates a severe marine environment.  
  • FoS simulates sulfurous atmospheres from air pollution.  
  • MFG simulates and amplifies the types of gases that may be found in some industrial environments.


Watch how vehicles create a harsh environment for electronics

HZO PRO750 Parylene Coating Equipment

Image Courtesy of CALCE, University of Maryland

The image above shows examples of electronics before and after being exposed to MFG and the non-coated and acrylic-coated (AR1) samples show signs of corrosion, while the Parylene-coated (XY) sample doesn’t. 

Impressive Physical Properties 

Parylene exhibits many beneficial physical properties that make it a reliable corrosion-resistance solution:

Water absorption after 24 hours:


Parylene C
Parylene F
Parylene N

Water Absorption

< 0.1% (0.125")
< 0.8%
0.8% to 2.9%
< 0.1%
< 0.1%
< 0.1%

The MTVRs of the Parylenes are among the lowest of polymers:


Parylene C
Parylene F
Parylene N



To learn more about Parylene properties, speak to one of our SMEs today.

Download our automotive fact sheet

In the late 1970s, the cost of electronics comprised around 5% of a vehicle’s total cost, but by 2030, components will comprise 50%.

The Big Picture 

At HZO, your unique reliability challenges drive our development of new processes and chemistries, but Parylene is a critical part of our tool kit. Although Parylene’s application method, chemical vapor deposition (CVD), is costlier and slower to finish, the process allows for deep penetration into substrate surfaces, resulting in the highest levels of protection available for automotive components.

With confidence in our engineers, material science, SMEs, and processes, we’ve come to understand your problems, and we’ve come to understand how we can help solve them. We’ve developed an elegant solution to your challenges with large capacity coating chambers that are cubed, allowing for more substrates to coat simultaneously, bolstering reliability, and driving down cost. Up to two times more parts can be coated at once.

We know that automotive engineers and manufacturers are looking for a partnership, not a “buyer/seller” relationship, so we are open to implementing different ideas and flexibility, configuring specific solutions for unique problems so that we may earn your trust.

With lives at stake, we understand the criticality of component reliability and the importance of your position. That’s why we put our all into protecting what matters most to you.

View a webinar about improving automotive electronic performance in harsh service environments 

Parylene exhibits many beneficial physical properties that make it a reliable corrosion-resistance solution.

Mallory McGuinness

Mallory is an electronics protection evangelist who writes content for HZO. In her free time she is reading non-fiction, and hanging out with her beta fish, King Awesome.

Ryan Moore

Ryan is a 9-year veteran to the world of protecting electronics from harsh environments and a lover of all things technology.

Discover how HZO can protect your product