What are the important physical properties of a conformal coating material?

When thinking about a conformal coating’s physical properties then I always consider that there are three states.

They are the properties during the:

  • Liquid Stage (When the conformal coating is a liquid ready for production).
  • Process Stage (During the conformal coating process).
  • Dry Stage (When the conformal coating has dried and or cured).

The key properties will vary depending on which state you are looking for.

For example, for the liquid state the critical properties for the conformal coating  include:

  • Flash point
  • Storage lifetime
  • Appearance and colour
  • Density
  • Solids content
  • Viscosity

These properties are important for the conformal coating process and completely influence the outcome of the production line.

However, for the process state the critical properties the conformal coating exhibits include:

  • Wetting
  • Capillary
  • Viscosity
  • Wet Film Thickness
  • Surface Tension
  • Pot life
  • Drying and curing

These properties of the conformal coating material will again influence the final outcome.

Finally, for the dry state the critical properties of the conformal coating include:

  • Abrasion Resistance
  • Chemical Compatibility and Resistance
  • Coefficient of Thermal Expansion
  • Corrosion Resistance
  • Edge Loss
  • Flammability
  • Flexibility
  • Fungus Resistance
  • Glass Transition Temperature
  • Hydrolysis Stability
  • Outgassing
  • Permeability
  • Refractive Index
  • Temperature Gradient
  • Thermal Shock
  • Thermal Stability
  • UV Stability

Note, there are a lot of physical properties but many not be important to you.

Also, most of these physical properties may be defined by the manufacturer and contained on a data sheet.

However, many other properties may be required and you may need to test.

To find out more click key physical states for conformal coating.

Or Contact Nexus now and let us show you how we can help you.


Dr Lee Hitchens, Author of Nexus website and ebook

Dr Lee Hitchens is the Author of the Nexus eBook and a main contributor to Nexus.

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What are the critical physical properties for a conformal coating when dry?

Sticking conformal coating reduced sizeThe physical conformal coatings properties can be subdivided into three key areas.

These are:

  • Liquid
  • Process
  • Dry State

They can be further subdivided into many different individual properties dependent on the type of chemistry of the coating.

Dry State

Once the conformal coating is applied and is fully dried / cured then it will have reached its full potential physical properties. This is the dry state.

Critical properties include:

  • Edge Loss
  • Refractive Index
  • Glass Transition Temperature
  • Coefficient of Thermal Expansion
  • Temperature Gradient
  • Flammability
  • Flexibility
  • Abrasion Resistance
  • Hydrolysis Stability
  • Permeability
  • Chemical Compatibility and Resistance
  • Corrosion Resistance
  • Fungus Resistance
  • UV Stability
  • Outgassing
  • Thermal Stability
  • Thermal Shock

Click to find out more on the dry state properties of conformal coatings.