Preparation of high dispersed nickel pastes for thick film electrodes

Ultra-thinning of Ni paste films for BMEMLCC (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 (g = 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 (Ra = 0.10 lm and Rmax = 0.97 lm) at a viscosity (g = 2.80 · 105 mPas at 0.1 s–1) adaptable to screen-printing. In addition, the Ni paste/thick film had the low sheet resistivity (q = 1.11 · 10–4 Wcm) and an excellent microstructure after sintering at 1,290 C for 3 h in a 97% N2/3% H2 atmosphere.