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- 저자 : Frank Edwin (검색결과 2 건)
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Nanocrystalline α-Al2O3 powder preparation with sucrose as a template through a chemical route
Rifki Septawendar,Suhanda,Frank Edwin 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.4
Nanocrystalline α-Al2O3 powder was prepared through a chemical route via a reaction between aluminum nitrate nona hydrate with a sucrose template in variation ratios of the salt to the organic namely 1 : 2, 3 : 1, and 6 : 1 at a heating temperature of 200 oC. The homogenization process of the nanopowder was assisted by milling a“charcoal precursor” in a non polar solvent for 24 hours, which was then successfully calcined at temperatures of 900 oC and 1100 oC. The products were evaluated by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The optimum condition was obtained at a ratio of the aluminum salt to the organic compound of about 6 : 1, at a calcination temperature of 900 oC, which produced a 100% pure α-Al2O3 phase with a crystallite size of 44.6 nm. The SEM micrographs showed the particle sizes of nanocrystalline α-Al2O3 powders were found to be near 100 nm at 1100 oC. The TEM results indicate that nanocrystalline α-Al2O3 powders calcined at 900 oC had grain sizes below 50 nm. An increase of the sucrose concentration leads to smaller crystal sizes, meanwhile an elevation of the calcination temperature from 900 oC to 1100 oC leads to the formation of larger particle and crystal sizes of alumina.
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Nanocrystalline ZrO2 powder preparation using natural cellulosic material
Rifki Septawendar,Bambang Sunendar Purwasasmita,Suhanda,Leanddas Nurdiwijayanto,Frank Edwin 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.1
Nanocrystalline zirconia powder has been successfully prepared using a precursor calcination process involving hydrolysis of zirconium(IV) isopropoxide and utilizing Oryza Sativa pulp (Merang Pulp) as the cheapest natural template. The potential of Oryza Sativa pulp as a template in the preparation of nanocrystalline zirconia is investigated in this research. It is also shown that the presence of the pulp can produce zirconia in nanocrystallites because the agglomeration tendency has been reduced in the as-synthesized ZrO2 particles. The effect of the calcination temperature on this zirconia preparation is found out by variation of the applied calcination temperature. XRD characterization shows monoclinic zirconia as a fully dominant phase,and the largest ZrO2 crystallite is found to be 42.7 nm. However, the zirconia crystallite size will increase with an elevation of the calcination temperature.
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