The sintering and microwave dielectric characteristics of MgO-CaO-Al_2O_3-SiO_2 glass-fluxed Ba(Mg_(1/3)Ta_(2/3))O_3 ceramics

摘要

Samples of 6 wt.% MgO-CaO-Al_2O_3-SiO_2 (MCAS) glass-fluxed Ba(Mg_(1/3)Ta_(2/3))O_3 ceramics are investigated, and its sintering and microwave dielectric properties are measured. The densification of the MCAS-fluxed Ba(Mg_(1/3)Ta_(2/3))O_3 ceramics can be performed well at 1350℃. Although the 1350℃-sintered Ba(Mg_(1/3)Ta_(2/3))O_3 ceramics own 96.3% theoretical density, the satellite phases of Ba_5Ta_4O_(15), Ba_4Ta_2O_9, Ba_7Ta_6O_(22) and Mg_4Ta_2O_9 are difficult to eliminate completely. As the sintering temperatures increase from 1250 to 1450℃, the microwave dielectric properties of MCAS-fluxed Ba(Mg_(1/3)Ta_(2/3))O_3 ceramics change as follows: The ε_r values first decrease, saturate at 1350℃-sintered ceramics and then slightly increase. The Q x f values first increase, saturate at 1350℃-sintered ceramics and then slightly decrease. The τ_f values linearly shift from 95.3 to -39.9 ppm/℃.