The main objective of this project was to develop a low contact resistance passivate coatings for electrical system components. The coatings inhibited the build-up of resistive corrosion on electrical connector backshells as well as on steel components that are commonly used in electrical equipment. The coated components demonstrated superior corrosion resistance compared to the respective steel and ZnNi components.
The developed coatings were based on assemblies of superhydrophobic diatomaceous earth and silica particles. To enhance the corrosion resistance and achieve low electrical resistance, exfoliated graphene sheets were dispersed in polydimethylsiloxane and the electrically conductive suspension was impregnated inside the porous patterns of the silica and diatomaceous earth particles. Amorphous silica nanoparticles were synthesized using sol-gel techniques. The particles were fluorinated to impart them with superhydrophobic properties. The graphene nanoplatelets were exfoliated using ultrasonic agitation and high-shear mixing techniques.
The synergistic effects of the water repellency, and moisture and oxygen barrier resulted in an impermeable coating that protected metal components from corrosion (proof-of-concept). The assemblies of graphene nanoplatelets, and superhydrophobic silica particles demonstrated excellent corrosion resistance. The samples retained their superhydrophobic properties and were corrosion free after 240 h of salt-fog testing.
The coatings can be applied to steel components, steel components coated with zinc-nickel and electrical connectors through an aerosol spray process. Corrosion in electronic components cannot be readily detected and is the predominant cause for electronic component failures when electrical equipment is exposed to environmental conditions. The developed coatings are inexpensive and scalable and can potentially be utilized to effectively protect critical infrastructure from corrosion. The developed coatings are compatible with coatings that are currently being used in electronic components (i.e. zinc-nickel).