• 한국전기화학회:학술대회논문집
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• 2000.04a
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• pp.31-31
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• 2000

• The Journal of Advanced Prosthodontics
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• v.6 no.2
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• pp.138-145
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• 2014

Cobalt-Chromium (Co-Cr) alloys are classified as predominantly base-metal alloys and are widely known for their biomedical applications in the orthopedic and dental fields. In dentistry, Co-Cr alloys are commonly used for the fabrication of metallic frameworks of removable partial dentures and recently have been used as metallic substructures for the fabrication of porcelain-fused-to-metal restorations and implant frameworks. The increased worldwide interest in utilizing Co-Cr alloys for dental applications is related to their low cost and adequate physico-mechanical properties. Additionally, among base-metal alloys, Co-Cr alloys are used more frequently in many countries to replace Nickel-Chromium (Ni-Cr) alloys. This is mainly due to the increased concern regarding the toxic effects of Ni on the human body when alloys containing Ni are exposed to the oral cavity. This review article describes dental applications, metallurgical characterization, and physico-mechanical properties of Co-Cr alloys and also addresses their clinical and laboratory behavior in relation to those properties.

• Journal of Korea Foundry Society
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• v.14 no.1
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• pp.28-34
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• 1994

Metallurgical-grade polycrystalline silicon was directionally solidified at growth rates of $0.2{\sim}1.0mm/min$ by using split type, reusable graphite molds which were coated with $Si_3N_4$ powder. The resultant grain sizes of the silicon ingots and the shapes of the solid/liquid(S/L) interfaces were investigated. X-ray diffraction was used to determine the preferred orientation in each of the silicon ingots. The impurity content of the silicon was analyzed and the resistivities of the ingots were measured. During the growth of an ingot, the shape of the S/L interface was concave to the silicon melt, and the resistivity decreased. The presence of Al which can be acting as a carrier, is thought to be the main factor causing such a decrease in resistivity. When a growth rate of 0.2㎜/min was used, the preferred orientation was found to be (111).

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.321-335
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• 1999

Erbium(Er) doped LiNbO3(Er:LiNbO3) single crystal gibers were grown free of cracks along the c-axis by micro-pulling down method. the Er3+ concentration was distributed homogeneously along the growth axis. The samples for optical characterization were cut from as-grown single crystal fibers and polished. When the 980 nm light was incident on the sample, upconversion phenomena were observed at the green range of wavelength 510~570 nm. In addition, the intensity of upconversion was remarkably increased by increasing the concentration of Er2O3 dopant in as-grown Er:LiNbO3 crystals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.377-380
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• 1999

Erbium (Er) doped $LiNbO_{3}(Er:LiNbO_{3})$ single crystal fibers were grown free of creacks along the c-axis by micro-pulling down method. The $Er^{3+}$ concentration was distributed homogeneously along the growth axis. The samples for optical characterization were cut from as-grown single crystal fibers and polished. When the 980nm light was incident on the sample, upconversion phenomena were observed at the green range of wavelength 510~570nm. In addition, the intensity of upconversion was remarkably increased by increasing the concentration of $Er_{2}O_{3}$ dopant in as-grown $Er:LiNbO_{3}$ crystals.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.557-558
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• 2006

In all conventional sintered PM products, the pores present are of two types, primary and secondary. Primary pores forming during compaction and latter during sintering, due to penetration of formed liquid through the matrix grain boundary. Effect of carbon addition on diffusion of Cu in SH737-2Cu system was investigated. After compaction and transient liquid phase sintering at $1120^{\circ}C$ and $1180^{\circ}C$, samples were characterized for densification, showing rise in sintering density and reduction in swelling on carbon addition. Quantitative microstructural characterization (shape factor and pore size) revealed bimodal distribution for 0% carbon, more rounded pores for 0.9% carbon and higher sintering temperature, and pore coarsening at higher sintering temperature.

• Journal of Powder Materials
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• v.19 no.1
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• pp.67-71
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• 2012

The present paper gives an overview about the Atom Probe Tomography technique and its application to powder materials. The preparation of needle-shaped Atom Probe specimens from a single powder particle using focused-ion-beam milling is described. Selected experimental data on mechanically alloyed (and sintered) powder materials are presented, giving insight into the atomic-scale elemental redistribution occurring under powder metallurgical processing.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.852-858
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• 2006

It is well known that $BaMgAl_{10}O_{17}:Eu^{2+}$ (BAM) and $CaMgSi_2O_6:Eu^{2+}$ (CMS) are a highly efficient blue phosphor. However, these phosphors in the form of thin films have not yet been realized clue to technical difficulties. We prepared thin film type BAM and CMS phosphors on quartz glass substrate using a pulsed laser deposition technique. The luminescent and structural properties of thin film phosphors were monitored as a function of key processing parameters such as oxygen partial pressure inside the deposition chamber, deposition time, laser energy density and the type of post-deposition treatments used. Even though we could not obtain single homogenous phases, thin films with large homogenous areas and a high photoluminescence could be produced by optimizing these processing parameters.

• Membrane and Water Treatment
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• v.6 no.3
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• pp.251-262
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• 2015

In this work the preparation and characterization of a membrane containing a uniform mesoporous Titanium oxide top layer on a porous stainless steel substrate has been studied. The 316 L stainless steel substrate was prepared by powder metallurgy technique and modified by soaking-rolling and fast drying method. The mesoporous titania membrane was fabricated via the sol-gel method. Morphological studies were performed on both supported and unsupported membranes using scanning electron microscope (SEM) and field emission scanning microscope (FESEM). The membranes were also characterized using X-ray diffraction (XRD) and $N_2$-adsorption / desorption measurement (BET analyses). It was revealed that a defect-free anatase membrane with a thickness of $1.6{\mu}m$ and 4.3 nm average pore size can be produced. In order to evaluate the performance of the supported membrane, single-gas permeation experiments were carried out at room temperature with nitrogen gas. The permeability coefficient of the fabricated membrane was $4{\times}10^{-8}\;lit\;s^{-1}\;Pa^{-1}\;cm^{-1}$.

• Journal of Electrochemical Science and Technology
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• v.6 no.2
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• pp.65-74
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• 2015

This work examines the characterization and corrosion behaviour of laser alloyed UNSG10150 steel with three different premixed composition Zn-Sn binary powders using a 4.4 kW continuous wave (CW) Rofin Sinar Nd:YAG laser processing system. The steel alloyed samples were cut to corrosion coupons, immersed in sulphuric acid (0.5 M H₂SO₄) solution at 30℃ using electrochemical technique and investigated for its corrosion behaviour. The morphologies and microstructures of the developed coated and uncoated samples were characterized by Optic Nikon Optical microscope (OPM) and scanning electron microscope (SEM/EDS). Moreover, X-ray diffractometer (XRD) was used to identify the phases present. An enhancement of 2.7-times the hardness of the steel substrate was achieved in sample A₁ which may be attributed to the fine microstructure, dislocations and the high degree of saturation of solid solution brought by the high scanning speed. At scanning speed of 0.8 m/min, sample A₁ exhibited the highest polarization resistance R_p (1081678 Ωcm² ), lowest corrosion current density i_corr (4.81×10⁻⁸A/cm² ), and lowest corrosion rate Cr (0.0005 mm/year) in 0.5 M H₂SO₄. The polarization resistance R_p (1081678 Ωcm² ) is 67,813-times the polarization of the UNSG10150 substrate and 99.9972% reduction in the corrosion rate.