Phase evolution and microwave dielectric properties of TiO2-modified (Mg0.95Co0.05)2TiO4 ceramics

Phase evolution and microwave dielectric properties of (1-x)(Mg0.95Co0.05)(2)TiO4-xTiO(2) (x = 0-1) ceramics prepared by the conventional mixed oxide route have been investigated. Increasing the TiO2 content would lead to a main phase transformation from (Mg0.95Co0.05)(2)TiO4 to (Mg0.95Co0.05)TiO3, (Mg0.95Co0.05)Ti2O5 and then TiO2. Not only did the TiO2 addition compensate the tau(f), it also lowered the sintering temperature of specimen. A huge drop of Q x f occurs at a 40-60 mol% TiO2 addition was attributed to the formation of (Mg0.95Co0.05)Ti2O5 phase. Specimen with x = 0.78 can possess an excellent combination of microwave dielectric properties: epsilon(r) similar to 24.77, Q x f similar to 38,500 GHz and tau(f)similar to-1.3 ppm/degrees C. (C) 2011 Published by Elsevier B.V.