Conductor pastes are the heartbeat of thick film circuits, defining how they perform under diverse demands. Silver, gold, and copper dominate, each with distinct traits. Silver’s affordability and conductivity (5.8 × 10⁷ S/m) make it a staple for wearables, though it migrates in humid conditions. Gold, pricier, resists corrosion and excels in biosensors for medical or aerospace use. Copper, fired in nitrogen to avoid oxidation, offers top conductivity for heaters and high power density designs.
A Materials Science Digest review details copper’s efficiency, though its inert firing adds complexity. Silver-palladium blends balance cost and stability, while platinum emerges for extreme environments. Pastes mix metal powders with glass frit, printed and fired at 850°C to bond with substrates. Conductivity varies—copper leads, silver follows, gold lags but endures.
Applications steer selection. Wearables favor silver for cost—think fitness trackers. Biosensors need gold’s reliability for patient safety, while heaters lean on copper’s power handling for industrial uses. Challenges include silver’s migration (mitigated by barriers), gold’s cost, and copper’s processing needs.
Design hinges on purpose. Silver suits consumer tech, gold aerospace, copper power electronics. Test adhesion—poor bonding fails circuits—and balance budget with performance. A well-chosen paste ensures traces endure vibration, heat, and time.