• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.37-44
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• 1995

TiO2 fine powders were synthesized using oxygenolysis and hydrolysis reaction of TiCl4 vapor in gas phase. The TiO2 powder synthesized showed morphological differences depending on reaction system as follows: TiCl4-O2 reaction system produced the monosized particles having polyhedral shape with well-defined crystal planes and the particles did not agglomerate into secondary particles. TiCl4-H2O reaction system, whereas, produced the spherical secondary particles which consisted of fine primary particles. Other powder characteristics such as particle size, impurity content and rutile content are also reported in this study.

• Journal of the Korean Ceramic Society
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• v.35 no.11
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• pp.1190-1196
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• 1998

Ultrafine ${\beta}$-SiC powders were synthesized by the vapor phase reaction of TMS[Si(CH3)4] in hydrogen The reaction temperature and TMS concentration were varied from 1000 to 1400$^{\circ}C$ and from 1 to 10% respectively. The average particle size and phase of the powders were analyzed by TEM and XRD. Ultrafine ${\beta}$-SiC powders were synthesized above 1000$^{\circ}C$ and the crystallinity of the powders increased with increasing reaction temperature. Shape of the particles were spherical and had average size of about 20 nm which showed no difference as the reaction temperature and TMS concentration increased. From the FT-IR analysis the absorption bands of Si-C of the powders shifted to higher wavenumber as the reaction temperature increased,. Under the condition of total gas flow above 1500cc/min ${\beta}$-SiC and poly-Si powders were obtained simultaneously. The Si-O bond intensity was increased under the condition of total gas flow rate above 1000cc/min which might be due to oxidation formed on poly-Si.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.14-14
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• 2001

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.10a
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• pp.14-15
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• 1997

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.10a
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• pp.34-34
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• 1997

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.11a
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• pp.37-37
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• 2005

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.04b
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• pp.47-47
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• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.10a
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• pp.57-58
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• 2003

• Journal of Powder Materials
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• v.19 no.3
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• pp.204-209
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• 2012

In this work, powder metallurgy and severe plastic deformation by high-pressure torsion (HPT) approaches were combined to achieve both full density and grain refinement at the same time. Pure Cu powders were mixed with 5 and 10 vol% diamonds and consolidated into disc-shaped samples at room temperature by HPT at 1.25 GPa and 1 turn, resulting in ultrafine grained metallic matrices embedded with diamonds. Neither heating nor additional sintering was required with the HPT process so that in situ consolidation was successfully achieved at ambient temperature. Significantly refined grain structures of Cu metallic matrices with increasing diamond volume fractions were observed by electron backscatter diffraction (EBSD), which enhanced the microhardness of the Cu-diamond composites.

• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.145.1-145.1
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• 2000