$Zn(NO_3)_2$의 첨가공정이 부분 공침법으로 제조된 $(Zr_{0.8}Sn_{0.2})TiO_4$ 유전체의 특성에 미치는 영향

The Effect of Adding Process of $Zn(NO_3)_2$ on the Properties of $(Zr_{0.8}Sn_{0.2})TiO_4$ Dielectrics Prepared by Coprecipitation of $(Zr^{4+}, Ti^{4+})$-Hydroxides in the Presence of $SnO_2$ Particles

ZST powders were synthesized by coprecipitation of (Zr4+, Ti4+)-hydroxide in the presence of SnO2 particles. Zn(NO3)2 was used as a sintering additive, and according to the adding sequence, sintering and dielectric properties were investigated. Sintered densities of ZST prepared by adding Zn(NO3)2 before calcination were a little higher than those added after calcination, and dielectric properties of the specimen added by Zn(NO3)2 after calcination were better (sintered at 125$0^{\circ}C$/2 h ; Q$\times$f(GHz)=49, 000, $\varepsilon$r=41) than before calcination (Q$\times$f(GHz)=42, 000, $\varepsilon$r=39.5). Through the observation of TEM, it was identified that the cause was due to the difference of the degree of Zn2+ diffusion into grains. With increasing sintering time from 2 to 8 hrs, grain size was doubled and dielectric properties were somewhat deteriorated.