Effect of zeta potential on coating morphology of SiO2-coated copper powder and conductivity of copper film

Abstract

In this study, the zeta potential on the surface of copper powder was adjusted by changing the pH value and adding cetyltrimethylammonium bromide (CTAB). Silica sol was coated directly on copper powder through physical adsorption. The as-prepared SiO2-coated copper powders were mixed with organic vehicle and screen printed on low-temperature co-fired ceramic substrate to form copper films. The binder-burn-out process of the films was carried out at 550 °C for 1 h in N2/H2O atmosphere and then sintered at 910 °C for 1 h in N2 atmosphere. The results proved that zeta potential had a major effect on the coating morphology of SiO2-coated copper powder. The SiO2-coated copper powder with a weight ratio of 1% showed a uniform and smooth surface. When the CTAB concentration was 1 × 10–4 mol/L, the copper powder exhibited the highest zeta potential of 98.2 mV, and the copper film had the best conductivity with a sheet resistance of 1.8 mΩ/□.