Effect of H3BO3 on the low temperature sintering and microwave dielectric properties of Li2ZnTi3O8 ceramics

The effects of H3BO3 addition on the sintering temperature, microstructure and microwave dielectric properties of Li2ZnTi3O8 ceramics were investigated. With H3BO3 addition, the densification of Li2ZnTi3O8 ceramics was improved significantly, the sintering temperature was lowered effectively, and the τf was adjusted to shift toward zero direction. In the case of 1.0 wt.% H3BO3 addition, the value of εr and Q × f reached maximum. With further H3BO3 addition, the dielectric properties were degraded due to the inferior microstructure. With 1.0 wt.% H3BO3, the Li2ZnTi3O8 ceramics sintered at 880 °C for 4 h showed excellent microwave dielectric properties of εr = 25.9, Q × f = 50,200 GHz, and τf = −6.8 ppm/°C.

► The addition of H3BO3 effectively lowered the sintering temperature of Li2ZnTi3O8 ceramics from 1075 to 880 °C.
► The nearly zero temperature coefficient of resonant frequency of −6.3 ppm/°C was obtained.
► Relationships between H3BO3 additives and microstructure evolution were investigated.
► Relationships between XRD peaks shift and τf values were evaluated.