Dependence of Electrode Ni Paste Properties on the Amount of Added BaTiO3 Powder.

Abstract

We evaluated the characteristics of Ni paste used for the fabrication of internal electrodes of multilayer ceramic chip capacitors (MLCs). The effect of addition of BaTiO3 powders to Ni paste on green density and sintering characteristics of electrode films were also evaluated. A green density of electrode film increased monotonically with an increase in the amount of BaTiO3 powder and showed the maximum value, 5.4g/cm3, at 15mass% BaTiO3. The experimental result reversed that the added BaTiO3 particles were located into three pocket of Ni particles up to 15mass% BaTiO3. However, the addition of more BaTiO3 powder (20mass%) resulted in decrease in green density of electrode film. Because an excess addition of BaTiO3 powder may cause random packing of BaTiO3 and Ni particles in electrode films. From the measurement of shrinkage of electrode film, it was observed that the shrinkage of electrode film decreased with an increased in the amount of BaTiO3 powder. The electrode films with 20mass% BaTiO3 powder showed the same tendency as monolithic BaTiO3. The results indicated that an addition of BaTiO3 to Ni paste prevented a sintering of Ni particles. The similar results were observed from SEM observation on the surface of sintered electrode film.