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        검색결과 3

        1.
        2020.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        CeO2 nanoparticles, employed in a lot of fields due to their excellent oxidation and reduction properties, are synthesized through a solvothermal process, and a high specific surface area is shown by controlling, among various process parameters in the solvothermal process, the type of solvent. The synthesized CeO2 nanoparticles are about 11~13 nm in the crystallite size and their specific surface area is about 65.38~84.65 m2/g, depending on the amount of ethanol contained in the solvent for the solvothermal process; all synthesized CeO2 nanoparticles shows a fluorite structure. The dispersibility and microstructure of the synthesized CeO2 nanoparticles are investigated according to the species of dispersant and the pH value of the solution; an improvement in dispersibility is shown with the addition of dispersants and control of the pH. Various dispersing properties appear according to the dispersant species and pH in the solution with the synthesized CeO2 nanoparticles, indicating that improved dispersing properties in the synthesized CeO2 nanoparticles can be secured by applying dispersant and pH control simultaneously.
        4,000원
        2.
        2012.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Y2O3 nanomaterials have been widely used in transparent ceramics and luminescent devices. Recently, many studies have focused on controlling the size and morphology of Y2O3 in order to obtain better material performance. Y2O3 powders were prepared under a modified solvothermal condition involving precipitation from metal nitrates with aqueous ammonium hydroxide. The powders were obtained at temperatures at 250˚C after a 6h process. The properties of the Y2O3 powders were studied as a function of the solvent ratio. The synthesis of Y2O3 crystalline particles is possible under a modified solvothermal condition in a water/ethylene glycol solution. Solvothermal processing condition parameters including the pH, reaction temperature and solvent ratio, have significant effects on the formation, phase component, morphology and particle size of yttria powders. Ethylene glycol is a versatile, widely used, inexpensive, and safe capping organic molecule for uniform nanoparticles besides as a solvent. The characterization of the synthesized Y2O3 powders were studied by XRD, SEM (FE-SEM) and TG/DSC. An X-ray diffraction analysis of the synthesized powders indicated the formation of the Y2O3 cubic structure upon calcination. The average crystalline sizes and distribution of the synthesized Y2O3 powders was less than 2 um and broad, respectively. The synthesized particles were spherical and hexagonal in shape. The morphology of the synthesized powders changed with the water and ethylene glycol ratio. The average size and shape of the synthesized particles could be controlled by adjusting the solvent ratio.
        3,000원