Preparation of high dispersed nickel pastes for thick film electrodes

Ultra-thinning of Ni paste films for BME-MLCC (Base Metal Electrode Multilayered Ceramic Capacitor) internal electrode was investigated. Adding various dispersants, ball-milling powder, and using the pre-dispersion process to improve Ni paste dispersion and properties of the paste electrodes/thick films, were employed. The paste containing 200 nm sized Ni powders, ethyl cellulose vehicle (η = 2.98 × 104 mPa-s at 0.1 s−1), and Emphos PS-21A as a dispersant proved to be the most desirable candidate. This paste thick film showed the smallest surface roughness (R a = 0.10 μm and R max = 0.97 μm) at a viscosity (η = 2.80 × 105 mPa-s at 0.1 s−1) adaptable to screen-printing. In addition, the Ni paste/thick film had the low sheet resistivity (ρ = 1.11 × 10−4 Ωcm) and an excellent microstructure after sintering at 1,290 °C for 3 h in a 97% N2/3% H2 atmosphere.