Structural characteristics of new high-Q (1−x)(Al1/2Ta1/2)O2–x(Mg1/3Ta2/3)O2 (0.2

The crystal structure and microstructure of microwave dielectric (1−x)(Al1/2Ta1/2)O2–x(Mg1/3Ta2/3)O2 (0.2≤x≤1.0) ceramics have been investigated. It is reported in the JCPDS cards that (Al1/2Ta1/2)O2 and (Mg1/3Ta2/3)O2 have orthorhombic and tetragonal structure, respectively. (1−x)(Al1/2Ta1/2)O2–x(Mg1/3Ta2/3)O2 ceramics had two phases of orthorhombic and tetragonal at low (Mg1/3Ta2/3)O2 concentration but as (Mg1/3Ta2/3)O2 concentration increased, (1−x)(Al1/2Ta1/2)O2–x(Mg1/3Ta2/3)O2 transformed into tetragonal structure. Specimens having tetragonal single phase could be obtained over x=0.6. As (Mg1/3Ta2/3)O2 concentration increased, the cell parameters, X-ray density, and the grain size increased. However, apparent density increased from 0.2 to 0.65 concentration of (Mg1/3Ta2/3)O2 and then decreased over 0.65 concentration of (Mg1/3Ta2/3)O2. The number and size of pores in grains also decreased from 0.2 to 0.65 concentration of (Mg1/3Ta2/3)O2 and then increased over 0.65 concentration of (Mg1/3Ta2/3)O2. It is expected that the relationship between structural characteristics and microwave dielectric characteristics have a good correlation.