Effect of fluxing additive on sintering temperature, microstructure and properties of BaTiO3

Abstract

Abstract. Various fluxing materials are added to technical ceramics in an attempt to lower their sintering temperatures and make their processing economical. The effect of 0·3 wt% Li 2 CO 3 addition on the phase, microstructure, phase transition temperatures and dielectric properties of BaTiO 3 was investigated in the present study. The addition of 0·3 wt% Li 2 CO 3 was observed to lower the optimum sintering temperature by ∼200 • C with no second phase formation and cause a five-fold reduction in grain size. Rhombohedral-to-orthorhombic and tetragonal-to-cubic phase transitions at the expected temperatures were evident from the Raman spectra, but the orthorhombic-totetragonal phase transition was not clearly discernible. The persistence of various phase(s) at higher temperatures in the flux-added materials indicated that the phase transitions occurred relatively slowly. A decrease in dielectric constant of Li 2 O-added BaTiO 3 in comparison to pure BaTiO 3 may be due to the diminished dielectric polarizability of Li + in comparison to Ba 2+ .

Novel BaTiO3-Based, Ag/Pd-Compatible Lead-Free Relaxors with Superior Energy Storage Performance

“…Excess 0.5 mol % Bi 2 O 3 was added to compensate for Bi-loss during processing and Li 2 CO 3 was used as a fluxing agent to reduce the sintering temperature. 57 − 59 Mixed powders were ball milled for 16 h, dried, and calcined 2 h at 900 °C. After calcination, the mixed powder was ball milled for 16 h, dried, and uniaxially pressed into 10 mm diameter pellets, followed by sintering 4 h from 1050–1200 °C.…”

“…A-site deficient x Bi 2/3 (Mg 1/3 Nb 2/3 )­O 3 –(1 – x )­BaTiO 3 ( x B 2/3 MN-BT) ceramics, with ( x = 0.00, 0.02, 0.04, 0.06, 0.08, and 0.10) solid solution were synthesized using a conventional solid–state reaction with analytical-grade raw powders of BaCO 3 (>99.5%), TiO 2 (>99.9%), MgO (>99.9%), Nb 2 O 5 (>99.5%), and Bi 2 O 3 (>99.9%). Excess 0.5 mol % Bi 2 O 3 was added to compensate for Bi-loss during processing and Li 2 CO 3 was used as a fluxing agent to reduce the sintering temperature. − Mixed powders were ball milled for 16 h, dried, and calcined 2 h at 900 °C. After calcination, the mixed powder was ball milled for 16 h, dried, and uniaxially pressed into 10 mm diameter pellets, followed by sintering 4 h from 1050–1200 °C.…”

Effect of sintering temperature on microstructure and electrical properties of Sr1−x(Na0.5Bi0.5) x Bi2Nb2O9 solid solutions

“…Increasing the amount of Bi 2 O 3 addition and sintering temperature enhancs the development of the preferred orientation and coarsening of grains [21]. In a recent work for BaTiO 3 compound, the addition of small amounts of Li 2 O to various ceramics has been reported to lower the sintering temperature by various mechanisms [22]. In another recent work, an addition of H 3 BO 3 effectively lowers the sintering temperature of Li 2 ZnTi 3 O 8 ceramics from 1075 to 880 [23].…”

Redesigning Multilayer Ceramic Capacitors by Preservation of Electrode Conductivity and Localized Doping

“…One can though of two mechanisms responsible for the high activation energy in coated MLCCs. First, Li 2 CO 3 has been used as a sintering aid in many systems. , It can improve the bonding (i.e., the interdiffusion) between the electrode and dielectric at the interface and increase the activation energy at the electrode interface . Second, the work function of the Ni electrode or the intermix layer between electrode and dielectric (i.e., the intermetallic layer of Ni, Ba, and Ti) may increase due to incorporation of Li ions.…”