Preparation of Ni paste using binary powder mixture for thick film electrodes

To achieve high dispersed Ni paste/thick film for BME-MLCC (base metal electrode multilayered ceramic capacitor) internal electrode, dispersion properties of paste/thick film using binary Ni powder mixtures were investigated. The viscosity of Ni paste containing binary powders is higher than that of Ni paste containing mono-sized powders regardless of mixing ratio of different sized Ni powders. On the other hand, the Ni paste containing 75 wt.% 500 nm powders and 25 wt.% 200 nm powders had the smallest surface roughness (Ra = 0.07 μm and Rmax = 0.61 μm). After drying at 100 °C in an air atmosphere, the microstructure of dried thick film exhibited an overall flatness on the cross-section and few voids on the top surface. These effects may be explained by the filling of grooves and voids among large powders during three-roller milling process.