Protect electronics.
Moisture, temperature fluctuations, vibration, dust, and various media can damage electronic assemblies. This overview will guide you to the appropriate protection method, from thin protective coatings to full potting and targeted encapsulation, and to suitable materials. SILITECH provides support with selection, datasheets, and alternatives, available from stock in Gümligen.
On this page
Stresses · Protection methods · Material families · Selection guide · By application · Selection criteria · Processing · Common errors · FAQ · Further information
Why protect
What damages electronics
Electronic assemblies rarely fail due to the component itself, but rather due to their environment. Depending on the application, multiple stresses act simultaneously, often for years and without the possibility of remediation. Proper protection begins with understanding the relevant stresses.
- Moisture and condensation lead to leakage currents, corrosion, and dendrite formation on conductor tracks.
- Temperature changes: create mechanical stresses due to differential expansion (CTE) of the component, circuit board and potting compound.
- Vibration and shock put stress on solder joints, wires and connectors, especially in vehicles, drones and military technology.
- Dust, media and chemicals: Oils, fuels, cleaners and salt spray attack unprotected components.
- Heat: Waste heat must be dissipated, otherwise lifespan and reliability will decrease.
- Electric fields and EMC: High voltage requires insulation, sensitive electronics require shielding against interference fields.
Method selection
Protection methods in detail
Six ways to protect electronics, from thin films to shielding. They can be combined.
Protective varnish (conformal coating)
Thin layer, repairable
A micrometer-thick protective layer against moisture and stray currents with minimal weight. Base materials vary depending on the type: acrylic, polyurethane, silicone, or parylene. Suitable when a light, broad-area base layer is sufficient.
Potting
Maximum protection
The assembly is completely encapsulated: maximum protection against media, vibration, and tampering. This results in a higher weight, and the system's rigidity should be appropriate for the component's load.
Encapsulation
Targeted rather than broad-based
Targeted encapsulation of individual areas or components, as a middle ground between thin coating and full potting. At the chip level, also known as globtop, underfill, or dam-and-fill.
Thermal management
Dissipate waste heat
Thermally conductive potting compounds, gap fillers, and thermal pastes dissipate heat from the assembly. The lambda value is product-dependent and can be found in the datasheet.
Electrical insulation
High voltage safe
For power and high-voltage electronics, dielectric strength, volume resistance, and tracking resistance (CTI) are important. Characteristic values according to the datasheet and relevant standard (e.g., IEC).
EMI/RFI shielding
Dampen interference fields
Conductive silicones and coatings seal and shield simultaneously against electromagnetic interference. Important in electronics, aerospace, and defense. Shielding attenuation varies depending on the product.
Chemistry
Material families in comparison
Most potting and coating systems are based on one of three chemical compounds. Each has a specific profile. Specific properties are product-dependent and can be found in the data sheet.
| Characteristic | epoxy | Polyurethane (PU) | silicone |
|---|---|---|---|
| strength | very high, hard | tough-elastic | soft, permanently elastic |
| Temperature range | high | medium | very high and very low |
| Mechanical stress on components | high | medium | low (low stress) |
| Media and chemical resistance | very good | good | good, media-dependent |
| Repairability / Rework | barely | conditional | often possible |
| Typical strength | robust, solid protection | impact-resistant potting compounds | Temperature changes, UV, flexibility |
Rule of thumb: Epoxy for maximum strength and media resistance, polyurethane for tough-elastic and impact-resistant potting, silicone for temperature-change and UV-stressed electronics with low mechanical stress and partial repairability.
Decision
Selection aid
| Requirement | More suitable | Notice |
|---|---|---|
| Lightweight moisture protection, repairable | Conformal coating (acrylic, PU, silicone) | fast, lightweight |
| rugged media and vibration protection | Full encapsulation (epoxy, PU, silicone) | Adjusting stiffness to component |
| High temperatures or flexibility | Silicone systems | Temperature range depends on the product |
| Dissipate heat | Thermally conductive potting compound, gap filler | Lambda value according to data sheet |
| High voltage and insulation | Potting compound with high dielectric strength | Characteristic values according to IEC and TDS |
| Shielding against electromagnetic interference (EMC) | conductive silicones and coatings | Shielding attenuation depends on the product |
| Space travel, vacuum | Low-outgassing systems | ASTM E595 (TML, CVCM) according to TDS |
| Lightweight construction (drones, aviation) | Coating instead of full potting where possible | Weighing weight against protection level |
The decisive factors in each individual case are geometry, load, temperature, media contact, and documentation. The specific parameters can be found in the respective technical data sheet.
According to use case
Typical use cases
What is required in practice, and where the choice of materials is particularly important.
Drones and UAVs
lightweight, vibration-resistant
Lightweight moisture protection and vibration resistance for flight controllers, GPS, and radios. Often coated instead of fully encapsulated to save weight. Aerospace.
Battery packs
thermal, insulating
Encapsulation and heat dissipation of cells and modules, often using thermally conductive, flame-retardant systems. E-mobility & batteries.
Sensors and cameras
precise, low-stress
Protection of sensitive sensors from moisture and vibration at low mechanical stress; partially optically transparent. Electronics & printed circuit boards.
High voltage
Breakdown, insulation
High-dielectric strength potting compounds for transformers, sensors, and power electronics. Energy & High Voltage.
Aerospace
Low Outgassing
Low outgassing in vacuum according to ASTM E595, wide temperature range, documented materials. Aerospace.
defense
Shock, salt spray
Shock, continuous vibration, salt spray, and large temperature fluctuations over extended periods of operation. Defense & Security.
specification
What you should clarify before making your selection
- Operating and peak temperatures as well as temperature changes.
- Heat dissipation: if significant power loss occurs, a thermally conductive solution is needed.
- Geometry and layer thickness: full encapsulation, encapsulation or thin coating.
- Mechanics: Vibration, shock, and how sensitive the components are to stress.
- Media: Moisture, oils, fuels, cleaners, salt spray.
- Electrical: voltage level, required dielectric strength, EMC.
- Repairability: must the assembly remain accessible later?
- Approvals: e.g. UL94 (fire class), Low Outgassing (ASTM E595), industry-specific certifications.
- Processing: Dosage, pot life, curing, quantity.
Using this information, we will jointly narrow down suitable products and review the data sheets.
processing
Process cleanly
- Mixing: with 2K systems, the mixing ratio must be adhered to exactly, otherwise curing and properties will suffer.
- Degassing: Remove air inclusions in a vacuum, especially in high-voltage and densely packed assemblies.
- Dosing: Static mixers and dosing technology ensure reproducible application.
- Curing: Pot life and curing conditions according to the data sheet; if necessary, temper for final properties and low outgassing.
- Pretreatment: clean, dry surfaces; primer or plasma treatment may be necessary for adhesion.
Caution: Inhibition: Platinum-curing silicones will not cure in contact with certain substances (tin, sulfur, amines, some adhesive tapes and plastics). If in doubt, perform a compatibility test on the original material.
From practice
Common mistakes
- Overly rigid system on a component subjected to temperature fluctuations: stress cracks at solder joints.
- Air inclusions in the potting compound: local weak points in insulation and heat dissipation.
- Thermal bonding underestimated: Coating instead of thermally conductive solution despite power loss.
- Inhibited platinum silicones due to contamination: sticky, uncured areas.
- Full potting without a rework concept, even though repair would be necessary.
FAQ
Frequently Asked Questions
Conformal coating or full potting?
Coating for lightweight, repairable basic protection against moisture at minimal weight. Full encapsulation when maximum protection against media, vibration and tampering is required and the additional weight is acceptable.
Epoxy, polyurethane or silicone?
Epoxy for maximum strength and media resistance, polyurethane for tough-elastic and impact-resistant potting, silicone for temperature changes, UV and low component stress with partial repairability.
How do I dissipate heat?
Via thermally conductive potting compounds, gap fillers, or thermal pastes. The lambda value in W/mK is product-dependent and can be found in the data sheet.
What applies to space travel and vacuums?
Low-outgassing materials are required there, evaluated according to ASTM E595 (TML, CVCM). The values are specified in the product-specific data sheet.
Can a potted seal be reopened?
Silicone potting compounds are often repairable, epoxies rarely. If rework is anticipated, this should be factored into the choice of material.
Further information
Matching products, worlds, articles & industries
Product groups: Resins & potting solutions · Silicone products · Adhesives & sealants · Surface treatment
Themed areas: Resins & potting solutions · Silicones · Adhesives & sealants
Knowledge articles: Conformal coatings compared · Potting vs. encapsulation · Thermally conductive potting compounds · Potting compounds for electronics · E-mobility battery assembly
Industries: Electronics & Printed Circuit Boards · E-Mobility & Batteries · Energy & High Voltage · Aerospace · Defense & Security
Terms: in the glossary (potting, conformal coating, dielectric strength, lambda value, low outgassing).
Technical basis: The information provided is for general guidance only and does not constitute a product guarantee. The manufacturer's data sheets (TDS) and relevant standards are binding. Specific characteristics (temperature range, lambda, dielectric strength, pot life, outgassing) are product-dependent.
contact
Unsure which protection is right for your assembly?
Describe the setup, environment, and load. We will check suitable materials, technical data sheets, and alternatives, including availability from our Gümligen warehouse.