Feature: Electronics labelling
The risk to assemblies is increased significantly when outgassing occurs within the substrate
Managing outgassing in modern
electronics By Jean-Luc Pizzol, Director of Business Operation, CILS International
S
horting, adhesion loss and supplier audit failure are some of electronics engineer’s worst nightmares. Tey are commonly attributed
to faulty parts, manufacturing errors or even just poor luck. However, there is a silent disruptor potentially lurking under each component and PCB, ready to wreak havoc on unprepared production lines. Te culprit’s name is outgassing. When not considered during material selection processes, outgassing can quietly undermine assemblies and cause serious disruption. So how does outgassing occur, how to stop it, and what is NASA’s role in all this?
The science of outgassing In simple terms, outgassing refers to the gradual release of volatile substances from a material’s surface or internal layers. Tese emitted compounds can migrate and condense onto nearby components, introducing contaminants that interfere with normal device functions, causing performance problems and even failures. Tus, materials with suboptimal outgassing characteristics can compromise the function and longevity of
40 June 2026
www.electronicsworld.co.uk
systems and precision instruments. For example, when outgassing occurs within proximity of a lens, conformal coating or contact surface, it can cause failures that are extremely difficult to diagnose post-assembly. As harmful as this can be, the risk to
assemblies is increased significantly when outgassing occurs beneath a component, within the substrate. Subsurface blisters that oſten form during processing are forced to expand when exposed to external environmental conditions like vacuums or high storage temperatures. Tese emissions can cause sections of adhesive, components or labels on the PCB to fail, creating contamination pockets. Tis leads to conditions that promote galvanic corrosion, both internally and between substrate layers. As this corrosion progresses, the accumulation of corrosion products and contaminants creates areas of blistering, cracking and pitting. At this point, the released gases can cause shorting and the operational failure of electronic assemblies.
Outgassing risk in electronics It is worth noting that outgassing in small quantities can be acceptable for many
electronic assemblies. In low-fidelity electronic environments and where inherently stable metals are used in PCB housings, or where low levels of moisture are factored into the design’s build, the phenomenon of outgassing can be little more than a mild annoyance. However, for manufacturers working with builds featuring moisture- or contaminant- sensitive components, preventing outgassing-related damage should be of great concern. For these cases, there are two ways
that manufacturers can opt to manage risk: through mitigating environmental accelerators or via strategic material choices. Reducing exposure of assemblies to extreme temperatures and pressurised vacuums can reduce outgassing exposure. Tere are many practical applications
where these conditions are simply unavoidable, like in aerospace. Low- pressure environments, such as the upper atmosphere, can cause exposed surfaces to start releasing trapped or volatile substances into the surrounding space more rapidly. Also to consider is that in automotive or
power electronics, PCBs can be thermally cycled above 100-125°C, or continuously run at about the boiling point of water.
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