Plasma-Deposited Gold Nanoparticles as a Green Alternative to ENIG Circuit Boards

Abstract

Next-generation space missions require electronics that can operate reliably under extreme radiation, thermal cycling, vacuum exposure and multi-year mission durations, while supporting increasingly demanding high-frequency communication and sensing systems. Commercial printed circuit boards (PCBs) finished with electroless nickel immersion gold (ENIG) remain widely used in aerospace, yet the Ni–P barrier layer introduces environmental, recyclability and high-frequency performance limitations that are becoming incompatible with emerging mission requirements and future visions of in-situ manufacturing. This work presents plasma-printed gold nanoparticle (AuNP) PCBs as a nickel-free, additive alternative platform designed to address these challenges. AuNPs synthesised via ultrasonic spray pyrolysis (USP) and deposited through plasma-assisted printing form gold conductive traces without chemical baths or multilayer structures. Demonstrations on alumina substrates show that the resulting microstrip transmission lines achieve insertion and return losses comparable to ENIG-finished PCBs up to 20 GHz, validating the approach for space-grade RF applications. Beyond performance parity, AuNP-based PCBs offer closed-loop recyclability and compatibility. Together, these results position plasma-printed AuNPs as a promising foundation for sustainable, high-frequency and space-ready electronics.