Formulation of screen printable cobalt nanoparticle ink for high frequency applications

Abstract

In this work, magnetic metallic cobalt nanoparticles with an average particle size of 28nm were processed as a dry powder with surface coating material and other organic additives to form a screen-printable ink to be cured at 110°C. EFTEM and TGA-DSC-MS-analyses were used to measure the thickness of the polymer, its coverage on cobalt nanoparticles and the inorganic solid content of the ink. The resolution of the printed patterns and the print quality were evaluated by surface profiler, FESEM and optical microscopy. The relative permeability of the thick film patterns with good printability was measured with a shorted microstrip structure over the frequency range of 0.2 to 4GHz and complex permeability values were calculated from measured scattering parameter data. The ink attained real part of complex permeability values of up to 5.13 at 200MHz with 70wt.% of magnetic filler. The developed ink can be utilized in various printed electronics applications such as antenna substrates and magnetic sensors.