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-mu-m 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-degrees-C for 3 h into bodies with > 96.0% of theoretical density. The dense sintered bodies of (Zr0.80Sn0.20)TiO4 showed good microwave characteristics: epsilon-r = 40.0, Q = 5000, and tau-t = 3 ppm/degrees-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.