Low-Fire Processing of BaTiO₃ with BaCuO₂–CuO

Abstract

The effects of a liquid-phase-sintering aid, BaCuO 2 -CuO (BCC), on the densification and dielectric properties of BaTiO 3 ceramics have been investigated. The densification temperature of BaTiO 3 is greatly reduced from 1300-1350 C down to 1050 C in the presence of BCC. This is attributed to a chemical reaction taking place at the interface of BCC/BaTiO 3 during firing. The BaTiO 3 dissolves into BCC, forming crystalline phases of BaCuO 2 , CuO, Cu 2 O and Ba 6 Ti 17 O 40 , and this enhances the densification kinetics of BaTiO 3 . For the samples with 2.0-2.5 wt% BCC, a high relative sintered density of >95% is obtained at 1050 C, and the resulting dielectric ceramics have a dielectric constant and dielectric loss in the range of 2200-2400 and <3% at 1 MHz, respectively.

Densification, microstructural evolution, and dielectric properties of hexagonal Ba(Ti1−xMnx)O3 ceramics sintered with fluxes

“…2(b)] indicate a major hexagonal phase, a minor phase of 12R polytype structure, and a trace amount of CuO phase in the ceramics. BaCuO 2 , a second phase observed in the literature [16], was not found in this study. Fig.…”

“…In the present study, [10][11][12][13][14][15][16], and followed by sintering at different temperatures. The effects of sintering aids on the densification, microstructural evolution, and microwave properties of the 6h-Ba(Ti 0.85 Mn 0.15 )O 3 ceramics were examined and discussed.…”

Improved efficiency of blue phosphorescence organic light‐emitting diodes with irregular stepwise‐doping emitting layers

“…In the device based on the (4,4 0 -N,N 0 -dicarbazole)biphenyl (CBP):FIrpic hostguest system, the performance was not influenced by three different stepwise-doping profiles (2-6-10%, 10-6-2%, 10-6-10% with direction from HTL to ETL), indicating that there is little hole and electron trapping effect in the device. The result is contradictory to the reports published previously [14,16]. In order to get a better understanding and further improve the performance of blue phosphorescent OLED, we have performed a detailed investigation on the effects of stepwise-doping profile.…”

“…However, these kinds of materials are rare and hard to design [7,8]. Based on a conventional blue phosphorescent dopant and their host materials, a common approach of improving the performance is to optimize the emitting layer (EML), such as introduction of a mixed-host architecture [9,10], double hosts [11], and stepwise EML [12][13][14][15][16], and so on.…”

“…The emitter has either hole-transporting or electron-transporting property, which is usually opposite to the host material. Lei et al [14] reported the first stepwise doping blue PHOLED by doping bis[(4,6-difluorophenyl)- (FIrpic) in N,N 0 -dicarbazolyl-1,4-dimethene-benzene (DCB) with varied concentrations of 5, 10, 20, and 45% in each step. The device showed a peak luminous efficiency of 15.4 cd A À1 , which is almost 80% higher than that of the conventional FIrpic-based PHOLED.…”