Conformal coating

Description

An uninterrupted coating that assumes the exact form or shape of the object. Most conformal coatings are thin, nonconductive, dielectric layers that were originally designed for the protection of electronics and electrical devices from moisture, contamination, chemicals, solvents, fungus, dust and corrosion. Because they are capable providing protection for a wide variety of substrates including metals, polymers, and semiconductors there use has expanded to include medical devices, automotive parts, consumer goods, and even works or art. Many types of polymers have been used for conformal coatings including, Acrylics, Epoxies, Silicones, Polyurethanes, Styrene and Parylene. One example, Parylene, is apllied via vapor deposited coating while more recent additions, such as Nanoproof and Vitroguard are available as solution-based coatings that can be dip or spray applied and requires little to no masking.

Synonyms and Related Terms

Product names: Parylene; Nanoproof; Aculon; Vitroguard; 3M Novec

Polymer Characteristics for Conformal Coatings

Polymer base	Advantages	Disadvantages	Application	Possible to remove?	water vapor transmission rate (g*mm/m2*day)	Service temperature	Average thickness	Commercial products
Acrylic	Low vapor phase transmission; does not shrink or give off heat when curing; low cost; clear	Can be easily damaged; low solvent resistance	Brush, spray or dip. Dry to touch in 10 minutes, typically cured within 24 hours.	yes	15.9	82 C	0.03-0.13 mm	AFA and HPA Electrolube
Epoxy	Extreme hardness, high strength and abrasion resistance; high resistance to heat moisture and solvents; can be pigmented	Removal of epoxy may cuse damage to underlying composnets	Brush, spray or dip. May shrink and produce heat when curing.	no	0.94	177 C	0.03-0.13 mm
Polyurethane	Excellent adhesion, high resistance to abrasion, moisture, chemicals and UV; low cost; clear	Can break down with heat	Brush, spray or dip. May take 1-30 days to cure.	no	0.9-3.4	121 C	0.03-0.13 mm	PUCAF
Silicone	Resistant to chemicals with low moisture penetration; withstands high temperature; provides thermal and vibration insulation; typicall pigmented	Relatively thick and soft; can be easily damaged; low solvent resistance	Brush, spray or dip. Typically cured within 1 hour.	maybe	1.7-47.5	260 C	0.05-0.21 mm
Parylene N	Ultra-thin coating that can provide excellent resistance to moisture, chemicals and solvents	Requires special application equipment	Applied with vapor deposition at room temeprature.	no	0.59	60-70 C	0.01-0.05 mm	Parylene N SCS
Amorphous fluoropolymer	Excellent resistance to oils, solvents and water; ultrathin	Requires special application equipment	Brush, spray or dip. Fast dry time					Fluorocoat; FPC

Risks

• Wear protective gloves and use fume hood for application
• Aculon is dissolved in a fluorocarbon solvent
• Aculon: SDS

Working Properties

• Applications methods: spray, jet, dip, vapor deposition

Resources and Citations

• Wikipedia: Conformal Coatings Accessed Feb. 2025
• Specialty Coating Systems: Conformal Coatings
• Aculon: NanoProof coatings Accessed Feb. 2025