Sinterability studies and microwave dielectric properties of sol–gel synthesized Ba(Zn1/3Ta2/3)O3 nanoparticles

Nanosized phase pure powder of Ba(Zn1/3Ta2/3)O3 (BZT) was prepared by sol–gel method and subsequent pyrolysis of the dried gel. The powders were pyrolyzed at different elevated temperatures and the effect of pyrolysis temperature on particle size was investigated. The sinterability of BZT ceramics made from nanopowders was found to be very high. Hence the sintered microstructure shows very large grains. However sintered density and microwave dielectric properties of sintered nanopowders were found to be poor. Reason for the poor densification was found to be the formation of large amounts of intergranular porosity and drastic grain growth during sintering. The samples were sintered by muffling with calcined BZT powder. Different sintering additives were added to calcined nanosized powders and then sintered. Most of the dopants are found to promote grain growth of sintered microstructure. Some of the dopants are found to reduce temperature coefficient of resonant frequency to zero when the average ionic radius was about 0.615 Å.