Microwave Sintering Modification of 85M<sub>7</sub>Z<sub>3</sub>CLT Microwave Dielectric Ceramics

The 0.85(Mg 0. 7 Zn 0. 3 )TiO 3 -0.15(Ca 0.61 La 0.26 )TiO 3 (referred to as 85M 7 Z 3 CLT) ceramics were fabricated by microwave sintering(MWS) and conventional sintering(CS) techniques. The effects of MWS and CS on the sintering property, crystal phase structure and dielectric properties of 85M 7 Z 3 CLT were discussed. Compared with CS, MWS had a short sintering period and a high volume density. The results indicated that the phase composition of 85M 7 Z 3 CLT ceramics were not changed after MWS, with (Mg 0. 7 Zn 0. 3 )TiO 3 and (Ca 0.61 La 0.26 )TiO 3 structure as the main crystal phase were also obtained by MWS. However, the grain growth was significantly inhibited due to the rapid sintering speed of MWS, which resulted in a fine, uniform microstructure. Furthermore, microwave-sintered ceramics had excellent dielectric properties due to the miscellaneous phase (Mg 0. 7 Zn 0. 3 )Ti 2 O 5 being suppressed. As a result, excellent dielectric properties of 27.11 for ε r , 103,500GHz for Q·f and +2ppm/°C for τ f were obtained by microwave sintering at 1275°C for 20 min. Therefore, the ceramic quality factor was increased by 22% compared with the conventional sintering.Key words: microwave technique; (Mg,Zn)TiO 3 ; dielectric ceramics