Yen-Lin Huang

A Study of Low-Temperature Sintering of (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 Ceramics with B2O3 Addition

The low-temperature sintering of (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 (BSTC) ceramics was investigated by conventional ceramics processing using a B2O3 sintering aid, and the dielectric properties and microstructures of the ceramics were examined. BSTC powders without B2O3 could not be fully densified at sintering temperatures lower than 1150°C. However, the addition of B2O3 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.% B2O3-doped BSTC ceramics sintered at 980°C for 2 h exhibited a high density of 5.48 g/cm3. Transmission electron microscopy examination indicated that there are two kinds of secondary phases produced in BSTC ceramics during B2O3 addition; one is BaTi(BO3)2 with rhombohedral structure, and the other is Ba4Ti12O27 with monoclinic structure. The BSTC ceramics with 3 at.% B2O3 sintered at 980°C in air for 2 h exhibited a maximum permittivity, ϵ max = 1216, and a bulk density > 96% of theoretical density.