Application of High Permittivity Bismuth Copper Titanate in Multilayer Capacitors

Abstract

A nonferroelectric high permittivity compound with the perovskite structure, Bi 2/3 Cu 3 Ti 4 O 12 , was synthesized at 900• C. The ceramic powder and appropriate organic additives were used for preparation of a slurry for tape casting. The obtained green tapes were smooth, flexible, and with a uniform thickness of 25 µm after drying at 50• C. Ag electrodes were screen printed on green rectangular sheets cut by a laser. Subsequent operations were screen printing of Ag internal electrodes, stacking of green sheets, isostatic lamination, cutting, deposition of external terminations and co-firing of dielectric and conductive layers at 850• C. Scanning electron microscopy observations showed well sintered, dense, fine-grained microstructure of ceramic layers and good cooperation with the electrodes made of commercial Ag paste. Capacitance and dissipation factor of multilayer capacitors were examined in the temperature range from −55 to 330• C at frequencies 10 Hz-2 MHz. The fabricated multilayer capacitors exhibit high capacitance and relatively low temperature coefficient of capacitance in the temperature range from −55 to 110• C. The obtained lead-free high permittivity nonferroelectric material Bi 2/3 Cu 3 Ti 4 O 12 is a spontaneously formed internal barrier capacitor. This material seems to be a promising alternative for conventional lead-based relaxor dielectrics in multilayer ceramic capacitors.

Dielectric properties of high-permittivity A2/3CuTa4O12 ceramics

“…Internal or surface barrier layer capacitance effects have been indicated as the origin of the high effective permittivity of this material (Subramanian et al, 2000, Sinclair et al, 2002, Prakash and Varma, 2006, Krohns et al, 2008, Ramirez et al, 2009, Schmidt et al, 2012, Thongbai et al, 2013. Similar properties have been found for some new, CaCu 3 Ti 4 O 12 -relative compounds, such as Bi 2/3 Cu 3 Ti 4 O 12 (Liu et al, 2004, Szwagierczak, 2009, Szwagierczak and Kulawik, 2012, Tan et al, 2010, ACu 3 B 4 O 12 (with A ϭ alkali, alkaline earth or rare earth; B ϭ Ru, Ti) (Ebbinghaus et al, 2009), Cu 2 Ta 4 O 12 (Ebbinghaus, 2007, Renner et al, 2004, Szwagierczak and Kulawik, 2008) and A 2/3 CuTa 4 O 12 (Szwagierczak and Kulawik, 2010, Szwagierczak, 2012.…”

Multifunctional antiferroelectric MLCC with high‐energy‐storage properties and large field‐induced strain

“…MLCC is made up of a ceramic body, in which alternating layers in parallel of conductive metal electrodes are embedded. In fact, as a kind of important passive component, MLCC is widely used in different electronic devices . However, the field‐induced phase transition and related multiple functions are rarely reported in lead‐based AFE MLCC up to now, to the best of our knowledge.…”

“…In fact, as a kind of important passive component, MLCC is widely used in different electronic devices. [10][11][12][13] However, the field-induced phase transition and related multiple functions are rarely reported in lead-based AFE MLCC up to now, to the best of our knowledge.…”

Investigation of the Microstructure and Chemical Composition of CaCu3Ti4O12 Multilayer Elements using SEM, EDS, and XPS

“…High dielectric constant and nonlinear current-voltage characteristics exhibited by these materials originate from spontaneous formation of internal barrier layers, mainly at grain boundaries. Potential applications of CaCu 3 Ti 4 O 12 -type compounds in low temperature cofired ceramics (LTCC) multilayer electronic components, like capacitors and varistors, have not been so far intensively investigated [8][9][10][11].…”