Regulation of Laser-Deposited Silver Microstructures on Ceramic Surfaces and Their Effects on Electrical Conductivity

Silver conductive structures were fabricated on 96% alumina ceramic substrates by selectively irradiating a silver nitrate precursor liquid film using a 355 nm Nd:YAG nanosecond laser under ambient conditions, without the use of external reducing agents. The effects of laser energy density, scan number, precursor concentration, plasma pretreatment, and PVP-30 addition on the morphology, composition, electrical conductivity, and adhesion of the deposited structures were investigated using XRD, SEM, EDS, contact angle measurements, resistance measurements, and tape-peeling tests. XRD confirmed the formation of metallic Ag in the laser-scanned regions. Insufficient laser energy density led to incomplete Ag⁺ reduction and discontinuous conductive paths, whereas excessive energy input caused hollow formation and Ag edge accumulation. A laser energy density of 12.03 J/cm² provided a favorable balance among structural integrity, Ag enrichment, and electrical conductivity. Increasing the scan number promoted particle coalescence and conductive network formation, while 1000 scanning cycles provided a suitable balance between structural continuity and dimensional precision. As the AgNO₃ concentration increased, the deposited structures evolved from isolated particles into continuous and compact layers, with 5 mol/L showing favorable deposition performance. Plasma pretreatment combined with PVP-30 addition reduced the contact angle of the ceramic surface from 48.25° to 19.05°, thereby improving the continuity, uniformity, and compactness of the deposits. After the scan spacing was reduced to form continuous silver films, the samples retained more than 98% of their conductivity after five tape-peeling cycles, with a resistivity of 6.14 × 10^-8 Ω·m. These results demonstrate that laser-induced deposition is a controllable strategy for fabricating conductive silver structures on ceramic surfaces.