Influence of metallic oxide additives on the synthesis and high-temperature dielectric properties of β-Yb2Si2O7

Abstract A pressureless solid-liquid reaction method was used to prepare β-Yb2Si2O7 powders in this article. Effects of different metallic oxides (Li2O, MgO and Al2O3) on synthesis process and high-temperature dielectric properties of β-Yb2Si2O7 were systematically studied. Chemical kinetics of synthesis process was calculated, and the apparent activation energy of Yb2O3/SiO2/Li2O, Yb2O3/SiO2/MgO, Yb2O3/SiO2/Al2O3 systems was calculated to be 42.98, 63.48, and 74.33 kJ/mol, respectively, which decreased by 77.3%, 66.5%, and 60.7% compared with that in additives free system. However, the microscopic network structure of intercrystalline glass phase formed by Li2O or MgO was looser than Al2O3 additive, leading to an intense structural relaxation polarization and a sharp increase in dielectric loss. β-Yb2Si2O7 prepared by adding Al2O3 had the best high-temperature dielectric performance. Its dielectric constant was less than 6, and the dielectric loss tangent was less than 2.5 × 10−2 from room temperature to 1200 °C in the range of 7–18 GHz. Such excellent dielectric property gave it the potential to be used as a wave-transmitting component at high temperature.