Comparative Analysis of Li2CO3 Doped (Ba,Sr)TiO3 and ZnBO Doped (Ba,Sr)TiO3 Ceramics for the Low Temperature Sintering Applications.

For the research on the LTCC(Low Temperature Co-fire Ceramic) applications, low temperature sintered ceramics have been extensively investigated. In this study, we have focused on the Li2CO3 doped (Ba,Sr)TiO3 and ZnBO doped (Ba,Sr)TiO3ceramics which have moderate dielectric properties such as high dielectric permittivity and low loss tangent. Until now, B2O3 has been commonly employed as the low temperature sintering aid. However, in this paper, we suggest Li2CO3 and ZnBO as alternative sintering aids to the B2O3. 1∼5 wt% of Li2CO3 or ZnBO was added to BST ceramics in order to reduce the sintering temperature. Li2CO3 doped BST and ZnBO doped BST ceramics were respectively sintered from 700°C to 1050°C and 750°C to 1250°C by 50°C to confirm the sintering temperature with different dopants concentrations. By adding Li2CO3 to the BST ceramics, the sintering temperature of BST ceramics was drastically lowered down to 900°C, whereas by introducing ZnBO dopants to BST, the loss tangent was decreased. From the XRD analysis, ZnBO doped BST ceramics have no pyro phase. 3 wt% Li2CO3 doped BST ceramics, which sintered at 900°C, have moderate relative dielectric permittivity of 1451 at 1 kHz, while 5 wt% ZnBO doped BST ceramics, sintered at 1100°C, have decreased dielectric permittivity of 1180 at 1 kHz. The loss tangent of ZnBO doped BST was decreased compared with that of BST. The loss tangent of ZnBO (1 wt%) doped BST was decreased down to 2.71 × 10-3 at 1 MHz. [ABSTRACT FROM AUTHOR]