폴리올법에 의한 편상의 은 분말 합성

Abstract

Monodispersed flaky silver powder was obtained by controlling the ratios of H2O2/NH3 and NH3/Ag in a mixed solution of ethylene glycol and ammonia with an addition of PVP. The effects of NH3/Ag, H2O2/Ag and H2PtCl6/Ag on its morphology and size were investigated. In H2O2-NH3-AgNO3 system, NH3/Ag molar ratio was found to be an important reaction factor for the nucleation and crystal growth of Ag powder. The synthesis of flaky powder was optimized at over 6 of NH3/Ag and 5 of H2O2/Ag under 1.0 × 10-3 of Pt/Ag. Moreover, as the NH3/Ag molar ratio increased, the size of precipitates was increased regardless of the amount of Pt. In the absence of H2PtCl, the morphology and size of reduced Ag powder were found to be irregular in shape 2-4 μm in diameter. However, homogenized fine Ag powder was obtained due to heterogeneous nucleation when H2PtCl used as a catalyst, and flaky one was synthesized with the addition of Pt over 1.0 × 10-3 of Pt/Ag.