• Journal of the Korean institute of surface engineering
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• v.21 no.4
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• pp.176-182
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• 1988

Effects of Cr, Ni and W on the anodic polarization behavior were investigated for Fe-Cr-Ni-W alloys in deaerated 1N HCI solution. Surface films formed on the polarization were analysed using AES, SEM and EDAX. A higerconcentration of tungten was found in the surface oxide film compared to the matrix. It played an importanet role on incresing the stability of the passive film. The presence of an adequate amount of Cr was essential to increase the pitting resistance of the alloys in acid chloride media. Under 12 wt%cr,alloys containing 6wt%W did not exhidit any passivity at all. The main role of Ni was to control the microstructure rather than to modify the corrosion resistance. In 23 cr-14Ni-^W alloy, the duplex microstructure of ferrite($\delta$-phase) in an austenic matrix was developed. The reson why proferred pitting appeared in austenite and ferrite/austenite interface was that ferrite had more amount of Cr and W than austenite.

• Journal of Korea Foundry Society
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• v.25 no.2
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• pp.73-79
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• 2005

Effects of Cr and Ni addition on damping capacity, mechanical property, and corrosion resistance of Fe-17%Mn martensitic alloy have been studied. Martensite start temperature($M_{S}$) of the alloy decreases linearly with increasing Cr and Ni contents up to 15%. The damping capacity decreases gradually from 27 to 22% in specific damping capacity(SDC) with increasing Cr and Ni contents from zero to 10%, and decreases rapidly with further Cr and Ni content in Fe-17%Mn alloy. The tensile strength of the alloy maintains a level of 60 $kgf/mm^{2}$ regardless of Cr content with an elongation of 20 to 25%. But, in case of Fe-17%Mn-x%Ni alloy, the tensile strength decreased rapidly with the Ni content of above 10% because of austenite morphology. Immersion test in 5% NaCl solution leads to the result that the corrosion resistance of the alloy becomes excellent above 10% Cr. From the above results, it is concluded that the optimum Cr content to improve the mechanical property and corrosion resistance of the alloy in 5%NaCl solution with a lesser decrease in damping capacity is about 10%. In the case of 5% $H_{2}SO_{4}$ condition, the Fe-17%Mn-10%Ni is an optimum alloy.

• Particle and aerosol research
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• v.8 no.2
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• pp.83-88
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• 2012

The electrical wire explosion process in liquid media is promising for nano-sized metal and/or alloy particles. The hybrid Pt/Fe-Cr-Al and Pt/Ni-Cr-Fe nanoparticles for exhaust emission control system are synthesized by electrical wire explosion process in liquid media. The alloy powders have spherical shape and nanometer size. According to the wire component, while Pt/Fe-Cr-Al nanoparticles are shown the well dispersed Pt on the Fe-Cr-Al core particle, Pt/Ni-Cr-Fe nanoparticles are shown the partially separated Pt on the Ni-Cr-Fe core particle. Morphologies and component of two kinds of hybrid nano catalyst particles were characterized by transmission electron microscope and energy dispersive X-ray spectroscopy analysis.

• Journal of the Korean Ceramic Society
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• v.44 no.11
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• pp.639-644
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• 2007

Spinel pigments, developing black color in high temperature glazes at oxidation or reduction atmosphere, without CoO because of its high price were synthesized by solid solution method. Ten mixed compositions consisted of NiO, MnO, $Fe_2O_3 and $Mn_2O_3$ were fired at $1250^{\circ}C$ for 1h. The resulting pigments were characterized by using XRD, FT-IR, SEM and UV-vis spectrometer. Structure of the pigments are spinel and particles' shape are spherical or cubic. Glazed tiles containing 5 wt% pigments were fired at $1260^{\circ}C$ and $1240^{\circ}C$ in reduction atmosphere. Color in glazes were analyzed by UV-vis spectrometer. Colors of NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.4875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0125 mole% and NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.3875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.1125 mole% in lime glaze showed black in oxidation, in reduction NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.4875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0125 mole% and NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.55{\cdot}Mn_2O_3$ 0.0125 mole% showed black. In case of lime-barium glaze, NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.3875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.1125 mole%, NiO 0.975 MnO $0.075{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% and NiO 0.925 MnO $0.075{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% showed black color in oxidation and NiO 0.875 MnO $0.125{\cdot}Fe_2O_3$ $0.3875{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.1125 mole%, NiO 0.925 MnO $0.075{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% and NiO 0.725 MnO $0.275{\cdot}Fe_2O_3$ $0.4375{\cdot}Cr_2O_3$ $0.50{\cdot}Mn_2O_3$ 0.0625 mole% showed black one in reduction.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.285-291
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• 2004

As a part of assessment of the structural material for the molten salt handling system, corrosion behavior of Inconel 718, X-750, Haynes 75 and Haynes 263 alloys in the molten salt of LiCl-Li$_2$O-O$_2$was investigated in the range of temperature; $650^{\circ}C$, time; 24~168h, $Li_2O$; 3wt%, mixed gas; Ar~10%$O_2$. In the molten salt of LiCl-$Li_2O-O_2$, the order corrosion rate was Haynes 263 ＜ Haynes 75 ＜ Inconel X-750 ＜ Inconel 718. Haynes 263 alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of alloys were as fellows: Haynes 75: $Cr_2O_4$, $NiFe_2O_4$, $LiNiO_2$, $Li_2NiFe_2O_4$, Inconel 718; $Cr_2O_4$, $NiFe_2O_4$, Haynes 263; $Li(Ni,Co)O_2$, $NiCr_2O_4$, $LiTiO_2$, Inconel X-750; $Cr_2O_3$, $NiFe_2O_4$,$FeNi_3$, (Al,Nb,Ti)$O_2$. Haynes 263 showed local corrosion behavior and Haynes 75, Inconel 718 and Inconel X-750 showed uniform corrosion behavior.

• Korean Journal of Materials Research
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• v.28 no.10
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• pp.595-600
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• 2018

This study investigates the microstructural properties of CoCrFeMnNi high entropy alloy (HEA) oxynitride thin film. The HEA oxynitride thin film is grown by the magnetron sputtering method using nitrogen and oxygen gases. The grown CoCrFeMnNi HEA film shows a microstructure with nanocrystalline regions of 5~20 nm in the amorphous region, which is confirmed by high-resolution transmission electron microscopy (HR-TEM). From the TEM electron diffraction pattern analysis crystal structure is determined to be a face centered cubic (FCC) structure with a lattice constant of 0.491 nm, which is larger than that of CoCrFeMnNi HEA. The HEA oxynitride film shows a single phase in which constituting elements are distributed homogeneously as confirmed by element mapping using a Cs-corrected scanning TEM (STEM). Mechanical properties of the CoCrFeMnNi HEA oxynitride thin film are addressed by a nano indentation method, and a hardness of 8.13 GPa and a Young's modulus of 157.3 GPa are obtained. The observed high hardness value is thought to be the result of hardening due to the nanocrystalline microstructure.

• 한국해양학회지
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• v.18 no.1
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• pp.49-54
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• 1983

sediments were collected from 23 ststions in Jinhae Bay and Cd, Cr, Cu, Fe, Ni, Mn, Pb and Zn were determined by atomic absorption spectrohotometry. The concentrations of Cd, Cr, Cu, Pb and Zn in the sediments decreased gradusally with increasing distance from the gead of Masan Bay, indicating pollutant transport from industrial and municipal wastewaters. But the levels of Co, Fe, Ni and Mn showed no difference througout the bay. analysis of correlation coefficients showed that Cd, Cr, Cu, Pb and Zn in the sediments were [losely associated to one another, whereas co, Fe and Ni were so associated.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.203-210
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• 2016

In this study, nine heavy metals were analyzed in seaweeds collected from market and laver culture farm of Korea and a food safety assessment were also carried out for these heavy metals. The level of heavy metal concentrations in seaweeds was in the following order: Fe>As>Zn>Cu>Cd>Pb>Cr>Ni>Hg. Except for zinc and cadmium, seven heavy metals were significantly higher in cultured laver than in processed laver. Significant correlation was observed Cr-Fe in cultured laver and Cu-Zn, Cd-Cu, Cd-Zn and Pb-Ni in processed laver and Cu-Cr, Cu-Zn, Cd-Cr and Ni-Fe in sea tangle and Zn-Fe, Cr-Fe, Cr-Zn, Cd-Ni, Cu-Cd and Cu-Pb in processed sea mustard. Considering differences in heavy metal concentration between processed laver and cultured laver and in correlation among heavy metals, removal efficiency of heavy metals may be attributed to seaweed treatment process. The average weekly intakes of Cu, Cd, Zn, Fe and Hg via seaweeds consumption were about 0.1~7.6% of PTWI (Provisional Tolerable Weekly Intakes). Therefore, it was found that heavy metals in the seaweeds were very safe for consumption.

• Journal of Welding and Joining
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• v.15 no.5
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• pp.46-55
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• 1997

This study has evaluated the liquation cracking behavior in the heat affected zone of several Ni base superalloys (Incoloy 825, Inconel 718 and Inconel 600). 304 and 310S austenitic stainless steels were also included for comparison. In addition, the mechanism of liquation cracking in the HAZ was postulated based on the extensive microstructural examinations with SEM, EDAX and TEM. The liquation cracking resistance of Ni base alloys was found to be far inferior to that of austenitic stainless steels. The liquation cracking of Incoloy 825 and Inconel 718 was believed to be closely related with the Laves-austenite(Ti rich in 825 and Nb rich in 718) and MC-austenitic eutectic phases formed along the grain boundaries by constitutional liquation and incipient melting under rapid welding thermal contraction. Further, liquation cracking resistance of the HAZ was dependent not only upon the type and amount of low melting phases but also on the grain size.

• Korean Journal of Environment and Ecology
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• v.13 no.2
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• pp.176-183
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• 1999

울산지역의 사문암과 유문암 토양 및 쑥과 참억새의 중금속 함량을 비교하기 위하여 중금속 농도를 분석한 결과 사문암 풍화토의 Ni, Cr 및 Co 함량은 매우 높았다. Ni은 1,483~1.524ppm, Cr은 372~435ppm, Co는 68~79ppm였으며, 유문암 풍화토의 Zn 함량은 222ppm으로 사문암 풍화토보다 높았다. 사문암 풍화토에서 생육하는 쑥의 중금속 함량은 Ni이 108~195ppm. Cr이 135~180ppm, Co가 10.2~22.5ppm으로 유문암 풍화토의 쑥보다 높았고, Zn은 유문암 토양 쑥에서 높았다. 참억새의 경우는 Ni, Cr, Co, As, Se, Mo 및 Fe 가 사문암 토양에서 높았고, Zn 흡수는 유문암 토양에서 많았다. 쑥의 중금속 함량은 대체적으로 지상부가 지하부보다 높았으나, 참억새의 경우는 지하부가 높은 경향을 나타내었다. 토양과 식물체(쑥과 참억새)의 중금속 함량을 비교해 보면 Ni, Cr, Co, As, Sc, Mo 및 Fe의 함량은 토양의 식물체보다 높았으나, 유문암 토양에 있는 쑥의 Zn 흡수는 토양보다 다소 높았다. 식물체의 Fe:Ni 비율은 유문암 토양보다는 사문암 토양이, 참억새보다는 쑥이 낮게 나타났다.