Phase evolution, microstructure, and dielectric properties of zinc orthosilicate, Zn2-2xSi1+xO4, sintered at 1350 oC wereinvestigated. 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 wereobserved clear, which indicates that the grain growths in these compositions were well developed. From these results, thecomposition of the synthesized zinc orthosilicate was assumed to be x = ~0.02, Zn1.96Si1.02O4, where Zn/Si is 1.922. The darkcoloredgrains having 0.52 of Zn/Si ratio were assumed to be the liquid phase in the sintering which promoted the liquid phasesintering. The specimens of x = 0.05, Zn1.9Si1.05O4, exhibited improved microwave dielectric characteristic of 6.27 in thedielectric constant and 104,323 GHz in the quality factor. The value of the quality factor for Zn1.9Si1.05O4 was much higher thanother specimens with different compositions, probably due to the effect of the grain boundaries.

Keywords: Zinc orthosilicate, Grain growth, Liquid phase sintering, Dielectric constant, Quality factor