Effect of glass doping for the sinterability of Ba(Mg1/3Ta2/3)O3 ceramics

Sintering of undoped Ba(Mg1/3Ta2/3)O3 (BMT) ceramics at 1500 °C gives BMT ceramics with 96.0% theoretical density and an ordering structure, but the satellite phases of Ba5Ta4O15, Ba4Ta2O9, Ba7Ta6O22, and Mg4Ta2O9 are difficult to eliminate completely. The addition of MgO–CaO–Al2O3–SiO2 (MCAS) glass as a sintering aid not only decreases the satellite phases of BMT ceramics but also improves the sinterability of BMT ceramics. The densification of the BMT ceramics can be performed well at lower temperatures of 1300–1350 °C. The satellite phases of Ba(Mg1/3Ta2/3)O3 powder can almost be eliminated at 1350 °C when 3 wt.% MCAS is used as a sintering aid or at 1300 °C when 6 wt.% MCAS is used as a sintering aid. When the sintering temperature is higher than 1350 °C and the amount of MCAS addition is equal to or more than 3 wt.%, the densities of BMT ceramics decrease with the increase of sintering temperature because of the increase of satellite phases and the melting of MCAS glass.