Preparation of high dispersed nickel pastes for thick film electrodes
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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 (Ra = 0.10 μm and Rmax = 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.
KeywordsThick Film Ethyl Cellulose Viscosity Variation Nickel Powder Internal Electrode
The authors would like to acknowledge the financial assistance of the Ministry of Information and Communication of Korea supported by the IMT-2000 project.