A Study of Low-Temperature Sintering of (Ba_0.6Sr_0.4)(Ti_0.94Cu_0.06)O₃Ceramics with B₂O₃Addition

Abstract

The low-temperature sintering of (Ba 0.6 Sr 0.4 ) (Ti 0.94 Cu 0.06 )O 3 (BSTC) ceramics was investigated by conventional ceramics processing using a B 2 O 3 sintering aid, and the dielectric properties and microstructures of the ceramics were examined. BSTC powders without B 2 O 3 could not be fully densified at sintering temperatures lower than 1150 • C. However, the addition of B 2 O 3 markedly enhanced the sinterbility of BSTC powders, and the sintering temperature decreased from 1150 to 980 • C. This may be due to the promotion of liquid-phase sintering. The 3 at.% B 2 O 3 -doped BSTC ceramics sintered at 980 • C for 2 h exhibited a high density of 5.48 g/cm 3 . Transmission electron microscopy examination indicated that there are two kinds of secondary phases produced in BSTC ceramics during B 2 O 3 addition; one is BaTi(BO 3 ) 2 with rhombohedral structure, and the other is Ba 4 Ti 12 O 27 with monoclinic structure. The BSTC ceramics with 3 at.% B 2 O 3 sintered at 980 • C in air for 2 h exhibited a maximum permittivity, ε max = 1216, and a bulk density > 96% of theoretical density.

Effect of Boron Deposition and Poisoning on the Surface Exchange Properties of LSCF Electrode Materials of Solid Oxide Fuel Cells

“…The significant grain growth of the particles on the LSCF surface is probably due to the effect of liquid-phase sintering caused by the low melting temperature of deposited boron. 41,42 The most remarkable change was observed on LSCF samples after heat-treatment in the present of E-glass at 800 • C for 48 h. The surface became rough and large number of small particles and nano-pores on the surface of LSCF grains were Figure 3 is the XRD patterns of the surface of LSCF bar samples with and without the presence of E-glass. Sharp XRD peaks reflect a well-developed crystallization and all the peaks can be indexed as a rhombohedral perovskite structure.…”

Thermally stable dielectric responses in uniaxially (001)-oriented CaBi4Ti4O15 nanofilms grown on a Ca2Nb3O10− nanosheet seed layer

“…In addition, the ε r of thin-film capacitors produced using (Ba, Sr)TiO 3 -based materials as the dielectric layer is severely degraded as the film thickness decreases, making it difficult to enhance the capacitance density by decreasing the film thickness8910. One possible reason for this sensitivity to film thickness may be the high strain sensitivity of ε r , which remains as the film thickness decreases.…”

“…This should allow the capacitor size to be scaled down or the total capacitance to be increased. In the case of (Ba, Sr)TiO 3 film capacitors, ε r is reported to change drastically not only with film thickness but also with temperature, which makes it difficult to design a capacitor with a small capacitance change over a wide temperature range8910. For (001)-oriented CaBi 4 Ti 4 O 15 films, the capacitance density reaches 4.5 μF/cm 2 as the film thickness is decreased to 50 nm, and the capacitance has a small temperature coefficient from room temperature to 400 °C despite the increase in the residual strain as the film thickness decreases.…”