Low Temperature Sintering of Lead-Free BaTiO₃-Based X9R Ceramics with Bi₂O₃ Dopant and Assisted by LiF-CaF₂ Flux Agent

Abstract

The sintering temperature of BaTiO3powder was reduced to 950°C due to the Bi2O3-LiF-CaF2addition.Excellent densification was achieved after sintering at 950°C for 10h. The low sintering temperature of newly developed capacitor materials allows a co-firing with pure silver electrodes.The dielectric constant and the temperature stability of the dielectric constant satisfied the X9R standard, which dielectric properties of were ε25°C1115, ΔC/C25°C±12% (55~200°C), tanδ1.5% (25°C).

Effect of Ta2O5 and Nb2O5 Dopants on the Stable Dielectric Properties of BaTiO3–(Bi0.5Na0.5)TiO3-Based Materials

“…Accordingly, Yuan et al and a few other researchers have recently started to work on the development of dielectric formulations capable of satisfying X9R specifications (−55 °C to 200 °C, ∆C/C25 °C ≤ ±15%) [5][6][7][8][9][10][11]. The utilization of an effective Curie-point shifter, such as (Bi0.5Na0.5)TiO3 or PbTiO3, to increase the Tc point along with the formation of the core-shell structure was found to be an effective method for obtaining high-temperature stability [12][13][14][15][16]. Dielectric formulations, including BaTiO3-based compositions, such as BaTiO3-(Bi0.5Na0.5)TiO3 [5,7,8,14,[17][18][19], BaTiO3-Bi(Zn0.5Ti0.5)O3 [16,20], and BaTiO3-Pb(Ti0.55Sn0.45)O3 [10] systems, and (Bi0.5Na0.5)TiO3-based compositions, such as (Bi0.5Na0.5)TiO3-BaTiO3-CaTiO3 [6,9,21] systems, have been developed recently to meet the temperature coefficient of capacitance (TCC) requirements of the X9R specifications.…”