• Journal of the Korean Ceramic Society
• /
• v.38 no.11
• /
• pp.959-961
• /
• 2001

Nanosized CeO$_2$Powders were prepared under high temperature and pressure conditions by precipitation from metal nitrates with aqueous potassium hydroxide. Spherical shape of CeO$_2$powder was obtained at 175$^{\circ}C$ for 6h. TEM and X-ray diffraction patterns showed that the synthesized particle was crystalline. The average size and size distribution of the synthesized particles were below 30 nm and narrow, respectively. In addition, the effects of synthesis parameters under hydrothermal process are discussed.

• Journal of Powder Materials
• /
• v.26 no.4
• /
• pp.340-344
• /
• 2019

Due to the rapid development of electricity, electronics, information communication, and biotechnology in recent years, studies are actively being conducted on nanopowders as it is required not only for high strengthening but also for high-function powder with electric, magnetic, and optical properties. Nonetheless, studies on nickel nanopowders are rare. In this study of the synthesis of nickel nanoparticles from $LiNiO_2$ (LNO), which is a cathode active material, we have synthesized the nanosized nickel powder by the liquid reduction process of $NiSO_4$ obtained through the leaching and purification of LNO. Moreover, we have studied the reduction reaction rate according to the temperature change of liquid phase reduction and the change of particle size as a function of NaOH addition amount using hydrazine monohydrate ($N_2H_4{\cdot}H_2O$) and NaOH.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2002.11a
• /
• pp.19-19
• /
• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 1999.10a
• /
• pp.12-12
• /
• 1999

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 1998.10b
• /
• pp.38-38
• /
• 1998

• Resources Recycling
• /
• v.27 no.2
• /
• pp.32-37
• /
• 2018

This study was conducted as a preliminary study for the recycling of palladium and palladium oxide. In this study, thermodynamic equations for the formation of palladium oxide (PdO) are established. Palladium chloride is dissolved into hydrochloric acid to generate a palladium chloride solution. Nanosized palladium oxide powder with an average particle size below 30 nm were generated from this raw material solution by means of a spray pyrolysis process. The palladium oxide particles were composed of a single solid crystal. The results of XRD analysis showed that only a PdO phase of the generated powder was formed. And, the specific surface area of the generated palladium powder was approximately $32m^2/g$.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2003.03a
• /
• pp.155-155
• /
• 2003

• Carbon letters
• /
• v.16 no.4
• /
• pp.233-240
• /
• 2015

Electrochemical synthesis was employed to prepare a novel hydroxyapatite/graphene (HAP/Gr) composite powder suitable for medical applications as a hard tissue implant (scaffold). The synthesis was performed in a homogeneous dispersion containing Na₂H₂EDTA·2H₂O, NaH₂PO₄ and CaCl₂ with a Ca/EDTA/PO₄³⁻ concentration ratio of 0.25/0.25/0.15M, along with 0.01 wt% added graphene nanosheets, at a current density of 137 mA cm⁻² and pH value of 9.0. The field emission scanning electron microscopy and transmission electron microscopy observations of the composite HAP/Gr powder indicated that nanosized hydroxyapatite particles were uniformly placed in the graphene overlay. Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction confirmed graphene incorporation in the HAP/Gr powder. The electrochemically prepared HAP/Gr composite powder exhibited slight antibacterial effect against the growth of the bacterial strain Staphylococcus aureus.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.173-175
• /
• 2003

At the low temperature of $950^{\circ}C$ the $\mu\textrm{m}$-sized whisker growth during the catalytic CVD of pyrolytic carbon from methane with $H_2$- and Ar-gas on quartz substrate with NiO powder was found in this work. In the preliminary study it was observed from pure methane pyrolysis without catalyst at the high temperature $1500~1700^{\circ}C$. If the growth whisker should be stopped at initial stage, about 20 min. of the methane pyrolysis, it would be nanosized whisker growth. The screw growth mechanism and unique mechanical properties of whisker for composites were also recognized. If the pyrolysis would be continued, we could found also spiral growth of whistlers with diameter of about 1, 5 mm. The large length of whisker was about 10 cm in 20 minute.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.3
• /
• pp.22-27
• /
• 2014

Nanosized zeolite was prepared in an autoclave at a hydrothermal temperature range of 100 to $170^{\circ}C$. In TEM and particle-size analyses, the size of the nanosized powders was found to be 10-300 nm, and its distribution is uniform and spherical, depending on the hydrothermal temperature. XRD confirms that the nanosized powder is MFI zeolite.