Production conditions and dielectric properties of microwave ceramics based on (1–x)((Mg0,2Zn0,8)TiO3–xCaTiO3 compositions

Abstract

The results of investigation of the temperature and frequency dependences of the dielectric characteristics of microwave ceramics of (1–x)((Mg_0,2Zn_0,8)TiO₃–xCaTiO₃ ((1–x)(MZT)–xCT) (0.1 ≤ x< 0.6) compositions synthesized from a mixture of oxides (the first method) and from a mixture of a pre-prepared solid solution of (Mg_0,2 Zn_0,8)TiO₃ and a CaTiO₃  compounds (the second method), as well as ceramics of these compositions doped at the stage of sintering 1–2 % tin and tungsten are presented. It is shown that the synthesized ceramics is a composite consisting of a mixture of phases formed on the basis of solid solutions of (Zn, Mg)₂ TiO₄ , (Zn, Mg)TiO₃  and the CaTiO₃  compounds, the ratio of which in ceramics depends on the composition of the initial mixture and the synthesis conditions. It is established that the dielectric constant (ε) of ceramics synthe sized from a mixture of oxides increases with increasing CaTiO₃ content in the (1–x)((Mg_0,2Zn_0,8)TiO₃–xCaTiO₃ system. This ceramics is characterized by small values of the temperature coefficient of dielectric constant (TK_ε ) and the dielectric loss tangent (tanδ) in the temperature range of 20–200 °C. For ceramics synthesized according to the second method, the high temperature stability of TK_ε and the small value of tanδ are observed in the temperature range of 20–150 °C. Doping ceramics with tin and tungsten oxides leads to an increase in ε and a decrease in dielectric losses.