Preventing Humidity-Induced PCB Failures: How Multiphysics Simulation Isolates Hidden Root Causes
Published: August 03, 2026
As modern technology scales, the demands on electronic hardware are shifting rapidly. The push for faster electric vehicle (EV) charging networks, high-density server farms, and offshore wind turbines has ushered in a new era of high-voltage, high-power electronics. However, operating at these elevated voltages brings an increased risk of catastrophic failure. While thermal management has historically dominated the safety conversation, an equally destructive—yet far more elusive—threat is ambient humidity.
The Hidden Threat: Moisture-Induced Degradation
When electronic assemblies operate in real-world environments, they are inevitably subjected to varying climatic conditions. Fluctuations in temperature and humidity lead to condensation forming on the surfaces of printed circuit boards (PCBs). This microscopic layer of moisture acts as an electrolyte, setting the stage for two primary destructive processes: electrochemical migration (ECM) and localized corrosion.
Under a DC bias, metal ions from the PCB’s tracks can dissolve into the moisture film and migrate toward the opposite electrode, forming conductive metallic filaments known as dendrites. Once these dendrites bridge the gap between conductors, they cause immediate short circuits. In high-voltage applications, these short circuits do not merely cause a system reset; they can generate intense localized heat, leading to smoke, component destruction, or even fire.
The "Unidentified" Root Cause Dilemma
Pinpointing corrosion as the definitive source of hardware failure remains a significant challenge for failure analysis engineers. It is estimated that up to half of all field failures in electronics are classified as having an "unidentified" root cause. When a device fails in the field and is returned to the lab for diagnostic teardown, the ambient moisture that caused the short circuit has often evaporated, leaving behind little to no visible trace of corrosion or dendrite growth.
To address this diagnostic blind spot, the Centre for Electronic Corrosion (CELCORR) at the Technical University of Denmark (DTU) has pioneered research aimed at modeling and predicting how moisture interacts with circuit designs before physical prototypes are even manufactured. Led by Dr. Rajan Ambat, the research group is bridging the gap between materials science and electrical engineering to develop robust, climate-resilient hardware.
Simulating the Microscopic Wet World
To evaluate how environmental conditions affect circuit reliability, the researchers at CELCORR collaborated with Aalborg University to construct multiphysics models using COMSOL Multiphysics software. By modeling a simplified PCB geometry, the team was able to simulate a 10-micrometer water film resting on the substrate surface, replicating the effects of high relative humidity.
Through these simulations, the team can dynamically adjust critical variables, including:
- The distance and spatial geometry between electrodes and conductors.
- The thickness and electrical conductivity of the condensing water film.
- Applied voltage differentials across adjacent traces.
- Ambient temperature fluctuations that drive condensation phases.
By computing the resulting electrochemical leakage currents across these parameters, the model provides a clear indicator of whether a specific PCB layout is highly susceptible to corrosion and subsequent failure. This predictive approach enables engineers to identify structural vulnerabilities early in the layout phase, long before committing to expensive production runs.
Democratizing Simulation with Custom Apps
While multiphysics modeling is incredibly powerful, it traditionally requires specialized expertise to configure and interpret. To make these insights accessible to their industrial partners, CELCORR utilized the Application Builder in COMSOL Multiphysics to create standalone, parameterized simulation applications.
These user-friendly apps present a simplified user interface, turning complex finite element analysis into a "plug-and-play" tool for PCB designers. Engineers can adjust physical parameters—such as cathode voltage, trace spacing, and blockage lengths—and immediately visualize the current density distribution and streamline plots of the electrolyte potential. This interactive capability allows hardware designers to benchmark different layout iterations and establish clear safety margins regarding maximum permissible humidity exposure.
Looking Ahead: Tertiary Models and High-Power Systems
CELCORR's research is continually evolving to address increasingly complex physics. Currently, the team is developing tertiary current distribution models to examine the precise mass transport properties and chemical reaction kinetics occurring within the electrolyte layer. Rather than treating the water film as a static conductor, these advanced models simulate the actual migration of chemical species and the rate-limiting chemical reactions driving the degradation process.
With a recent grant from the Grundfos Foundation, CELCORR has established the Centre for Climate Robust Electronics Design (CRED). This new facility is specifically dedicated to investigating the performance and reliability of high-voltage and high-power electronics operated under severe climatic stress. The ultimate goal is to generate actionable, open-access guidelines and advanced modeling workflows that help the broader engineering community build hardware capable of surviving the harshest environmental conditions.
Actionable Design Strategies for Developers
While access to advanced multiphysics simulation tools is ideal, embedded engineers and DIY makers can immediately implement several key design principles to minimize the risks of humidity-induced failure:
- Increase Creepage and Clearance: Ensure that high-voltage traces are separated by physical barriers or generous spacing to reduce the electric field strength, lowering the driving force for electrochemical migration.
- Apply Conformal Coatings: Use high-quality acrylic, silicone, or polyurethane coatings to establish a hydrophobic barrier over vulnerable components and solder joints, preventing direct contact with atmospheric moisture.
- Optimize Thermal Dissipation: Design thermal dissipation pathways to maintain a slightly elevated, stable localized temperature. Keeping the PCB surface slightly warmer than the surrounding ambient air prevents condensation from forming (dew point mitigation).
- Implement Potting Compounds: For extreme environments, fully potting the electronic assembly in epoxy or polyurethane ensures complete isolation from external moisture and corrosive agents.
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EDATA SL shares practical electronics, embedded systems, Arduino, ESP32, Raspberry Pi, IoT, repair guides, DIY projects and technical news for engineers, students and makers.
Original news rewritten with AI for educational purposes.
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