Chemical Processing and Microwave Characteristics of (Zr,Sn)TiO4 Microwave Dielectrics

Monosized spherical particles of (Zr, Sn)TiO₄ with an average diameter of about 0.3 μm were synthesized by the controlled hydrolysis of metal alkoxides. The as-prepared, amorphous, particles were compacted without any sintering aid, crystallized, and then sintered at 1600°C for 3 h into bodies with >96.0% of theoretical density. The dense sintered bodies of (Zr_0.80Sn_0.20)TiO₄ showed good microwave characteristics; ɛ_r= 40.0, Q = 5000, and τ_t= 3 ppm/°C at 10 GHz. The dielectric constant was remarkably dependent upon the relative densities of the sintered bodies and the change of the lattice parameters, while Q value was mainly affected by the oxygen deficiency. An increase of the dielectric constant with the substitution of Sn⁴⁺ in ZrTiO₄ was attributable to the enhancement of ionic polarization with the increase of the c -axis length.