• Title/Summary/Keyword: Surface microstructure

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Microstructure and Physical Properties of Sputtered Metal Containing Nanocrystalline Structured Carbon Coatings

  • Kim, Sung-I.;Han, Jeon-G.
    • Journal of Surface Science and Engineering
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    • v.40 no.2
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    • pp.59-62
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    • 2007
  • Metal containing hydrogen free nanocrystalline structured carbon (Me:nc-C) films were synthesized by closed-field unbalanced magnetron sputtering system (CFUBM). The aim of this study was to determine the relationship between the microstructure and physical properties of Me:nc-C films as a function of the concentration of materials. The film structures were examined by x-ray photoelectron spectroscopy and high resolution transmission electron microscopy. The physical properties of the Me:nc-C films were evaluated by using a 4-point probe. The fraction of graphite clusters was found to be increased by containing titanium and the electrical resistivity decreased with increasing amount of containing.

The Mechanism of Gold Deposition by Thermal Evaporation

  • Mark C. Barnes;Kim, Doh-Y.;Nong M. Hwang
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 2000.06a
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    • pp.127-142
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    • 2000
  • The charged cluster model states that chemical vapor deposition (CVD) begins with gas phase nucleation of charged clusters followed by cluster deposition on a substrate surface to form a thin film. A two-chambered CVD system, separated by a 1-mm orifice, was used to study gold deposition by thermal evaporation in order to determine if the CCM applies in this case. At a filament temperature of 1523 and 1773 K, the presence of nano-meter sized gold clusters was found to be positive and the cluster size and size distribution increased with increasing temperature. Small clusters were found to be amorphous and they combined with clusters already deposited on a substrate surface to form larger amorphous clusters on the surface. This work revealed that gold thin films deposited on a mica surface are the result of the sticking of 4-10 nm clusters. The topography of these films was similar to those reported previously under similar conditions.

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Study on Improvement of Surface Properties of SKD61 Powder on S45C Using Laser Cladding

  • Cheol-Woo Kim;Hyo-Sang Yoo
    • Archives of Metallurgy and Materials
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    • v.67 no.4
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    • pp.1465-1468
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    • 2022
  • In this study, we investigated the effect of cladding on structural carbon steel (S45C) using 5%Cr-1.5%Mo-Fe powder (SKD61), which is expected to show economically efficient production of die-casting parts. The process conditions were performed under argon atmosphere using a diode laser source with specialized wavelength of 900-1070 nm, and the output conditions were 3, 4, and 5 kW, respectively. After the cladding was completed, the surface coating layer's shape and the microstructure were analyzed. The hardness test was carried out with Micro Vickers hardness tester under 500 gram-force along the normal line at the interval of 0.2 mm from the surface to core direction on the cross-sectional area. In addition, polarization curve test of the surface coating layer was performed to investigate the corrosion resistance characteristics.

Microstructure and Characterisistics of Near Surface of $As^+$Ion Implanted Si (A$s^+$이온을 주입시킨 Si 표면부 미세구조와 특성)

  • Shin, D.W.;Choi, C.;Park, C.G.;Kim, J.C.
    • Korean Journal of Materials Research
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    • v.2 no.3
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    • pp.213-219
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    • 1992
  • The microstructure, dopant distribution and electrical properties of the $As^{+}$ ion-implanted surface layer differ significantly depending on the methods of subsequent heat treatments, furnace annealing(FA) and rapid thermal annealing(RTA). The amorphous layer created by ion implantation was recrystallized during the thermal annealing through solid phase epitaxial (SPE) growth. The dopant distribution and electrical properties are discussed with respect to the TEM cross-sectional microstructure observed. The microstructure, dopant distribution and electrical properties depended upon especially the annealing time of the heat treatment.

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Effect of Inductively Coupled Plasma on the Microstructure, Structure and Mechanical Properties of NbN Coatings (유도결합 플라즈마 파워가 NbN 코팅막의 미세구조, 결정구조 및 기계적 특성에 미치는 영향에 관한 연구)

  • Chun, Sung-Yong
    • Journal of Surface Science and Engineering
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    • v.48 no.5
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    • pp.205-210
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    • 2015
  • NbN coatings were prepared by ICP (inductively coupled plasma) assisted magnetron sputtering from a Nb metal target in $Ar+N_2$ atmosphere at various ICP powers. Effect of ICP on the microstructure, crystalline structure and mechanical properties of NbN coatings was investigated by field emission electron microscopy, X-ray diffraction, atomic force microscopy and nanoindentation measurements. The results show that ICP power has a significant influence on coating microstructure, structure and mechanical properties of NbN coatings. With the increasing of ICP power, coating microstructure evolves from the columnar structure of DC process to a highly dense one. Crystalline structure of NbN coatings were changed from cubic ${\delta}$-NbN to hexagonal ${\beta}-Nb_2N$ with increase of ICP power. The maximum nano hardness of 25.4 GPa with Ra roughness of 0.5 nm was obtained from the NbN coating sputtered at ICP power of 200 W.

Influence of Selective Oxidation Phenomena in CGLs on Galvanized Coating Defects Formation

  • Gong, Y.F.;Birosca, S.;Kim, Han S.;De Cooman, B.C.
    • Corrosion Science and Technology
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    • v.7 no.1
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    • pp.1-5
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    • 2008
  • The gas atmosphere in continuous annealing and galvanizing lines alters both composition and microstructure of the surface and sub-surface of sheet steel. The formation and morphology of the oxides of alloying elements in High Strength Interstitial Free (HS-IF), Dual Phase (DP) and Transformation-Induced Plasticity (TRIP) steels are strongly influenced by the furnace dew point, and the presence of specific oxide may result in surface defects and bare areas on galvanized sheet products. The present contribution reviews the progress made recently in understanding the selective formation of surface and subsurface oxides during annealing in hot dip galvanizing and conventional continuous annealing lines. It is believed that the surface and sub-surface composition and microstructure have a pronounced influence on galvanized sheet product surface quality. In the present study, it is shown that the understanding of the relevant phenomena requires a combination of precise laboratory-scale simulations of the relevant technological processes and the use of advanced surface analytical tools.