Phase evolution, microstructure, and microwave dielectric properties of Zn2-2xSi1+xO4

Phase evolution, microstructure, and dielectric properties of zinc orthosilicate, Zn2-2xSi1+xO4, sintered at 1350 degrees C were investigated. All sintered specimen in the composition of 0 <= x <= 0.1 showed dense microstructures. For the specimen of x = 0, low quality factor was obtained due to the insufficient grain growth. The grain boundaries in the specimens of x >= 0.05 were observed clear, which indicates that the grain growths in these compositions were well developed. From these results, the composition of the synthesized zinc orthosilicate was assumed to be x = similar to 0.02, Zn1.96Si1.02O4, where Zn/Si is 1.922. The dark-colored grains having 0.52 of Zn/Si ratio were assumed to be the liquid phase in the sintering which promoted the liquid phase sintering. The specimens of x = 0.05, Zn1.9Si1.05O4, exhibited improved microwave dielectric characteristic of 6.27 in the dielectric constant and 104,323 GHz in the quality factor. The value of the quality factor for Zn1.9Si1.05O4 was much higher than other specimens with different compositions, probably due to the effect of the grain boundaries.