Shrinkage behavior and interfacial diffusion in Ni-based internal electrodes with BaTiO 3 additive

• Published in: Ceramics international Vol. 34; no. 6; pp. 1487 - 1494
• Main Authors: Kang, Ji-Hun, Joo, Dongwon, Cha, Hyun-Min, Jung, Yeon-Gil, Paik, Ungyu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2008
• Subjects: B. Interfaces; C. Diffusion; E. Capacitors; Internal electrode; Internal electrode; B. Interfaces; C. Diffusion; E. Capacitors
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2007.04.010

The effects of particle size of starting materials and amount of a BaTiO 3 additive on the shrinkage behavior and elemental diffusion in Ni-based internal electrodes have been investigated in order to control the shrinkage of the internal electrode in multilayer ceramic capacitors (MLCCs). Two kinds of Ni and BaTiO 3 powders were used with different particle sizes. Volume shrinkage over the range of 700–1300 °C at 150 °C intervals and linear shrinkage during sintering were measured for starting materials and composites in a reducing atmosphere. The interfaces of Ni/BaTiO 3 composites with 90:10 and 70:30 volume ratios, respectively, were investigated using TEM. Composites with bimodal Ni powder show less shrinkage than those with monomodal Ni powder, showing less shrinkage in monolith Ni of bimodal particle size. The shrinkage behavior is changed during sintering with increasing amounts of BaTiO 3 additives in both Ni-based composites. The particle size of the BaTiO 3 additive affects the shrinkage behavior of composites, without the additional amount affecting the final shrinkage. A reaction layer of about 300 nm wide is observed at the interface between the Ni and BaTiO 3 powders in composites, in which elemental Ni diffuses into the BaTiO 3 without counterdiffusion.