Shrinkage behavior and interfacial diffusion in Ni-based internal electrodes with BaTiO3 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: Kidlington Elsevier Science 01.08.2008
• Subjects: Applied sciences; Dielectric, amorphous and glass solid devices; Electronics; Exact sciences and technology; Materials; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Particle size; Sintering; Multiple layer; Nickel; Barium titanates; Ceramic capacitor; Electrode material; Shrinkage; Composite material
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2007.04.010

The effects of particle size of starting materials and the amount of a BaTiO3 additive on the shrinkage behaviour and elemental diffusion in Ni-based internal electrodes were investigated in order to control the shrinkage of the internal electrode in multilayer ceramic capacitors (MLCCs). Two kinds of Ni and BaTiO3 powders were used with different particle sizes. Volume shrinkage over the range 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/BaTiO3 composites with 90:10 and 70:30 volume ratios, respectively, were investigated using TEM. Composites with bimodal Ni powder showed less shrinkage than those with monomodal Ni powder, showing less shrinkage in monolith Ni of bimodal particle size. The shrinkage behaviour changed during sintering with increasing amounts of BaTiO3 additives in both Ni-based composites. The particle size of the BaTiO3 additive affects the shrinkage behaviour of the composites, without the additional amount affecting the final shrinkage. A reaction layer of about 300 nm wide was observed at the interface between the Ni and BaTiO3 powders in the composites, in which elemental Ni diffused into the BaTiO3 without counterdiffusion. 24 refs.