Influence of B₂O₃ additions to 0.8(Mg_0.95Zn_0.05)TiO₃-0.2Ca_0.61Nd_0.26TiO₃ ceramics on sintering behavior and microwave dielectric properties

The effects of additive sintering aids on the microstructures and microwave dielectric properties of 0.8(Mg_0.95Zn_0.05)TiO₃-0.2Ca_0.61Nd_0.26TiO₃ ceramics were investigated. B₂O₃ was selected as a liquid phase sintering aid to lower the sintering temperature of 0.8(Mg_0.95Zn_0.05)TiO₃-0.2Ca_0.61Nd_0.26TiO₃ ceramics. With added B₂O₃, the densification temperature of 0.8(Mg_0.95Zn_0.05)TiO₃-0.2Ca_0.61Nd_0.26TiO₃ can be effectively reduced from 1350 °C to 1125-1250 °C. Low-level doping of B₂O₃ (0.5-4 wt.%) significantly improves the density and dielectric properties of 0.8(Mg_0.95Zn_0.05)TiO₃-0.2Ca_0.61Nd_0.26TiO₃ ceramics. The quality factor Q × f was strongly dependent upon the amount of additives. Q × f values of 21200 and 54900 GHz could be obtained at 1125-1250 °C with 0.5 to 4 wt.% B₂O₃ added, respectively. Over all ranges of addition, the relative dielectric constants differed significantly and ranged from 24.1 to 26.6. The temperature coefficient varied from 2.9 to 10.03 ppm/°C.