• Journal of Powder Materials
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• v.11 no.5
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• pp.383-390
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• 2004

In order to investigate behavior of abnormal expansion of the iron-copper compacts, we compared the dilatometric curves of the compacts which mixed the copper powder to the iron powder with those of compacts which mixed the copper powder to the iron-copper alloy powder. The dilatometric curves were obtained below the sintering conditions, which heated up to 115$0^{\circ}C$ by a heating rate of 1$0^{\circ}C$/min, held for 60min at 115$0^{\circ}C$ and cooled down at a rate of 2$0^{\circ}C$/min to room temperature. The dilatometric curves of the compacts showed the different expansion behavior at temperatures above the copper melting point in spite of same chemical composition. All of the compacts of former case showed large expansion, but all of the compacts in latter case showed large contraction. The microstructures of sintered compacts also showed the different progress in alloying of the copper into the iron powder. Namely we could observe the segregation at alloy part of copper into iron powder in case of the sintered compacts, which mixed the copper powder to the iron powder, but could not observe the segregation in compacts which mixed the copper powder to the iron-copper alloy powder. But the penetration of liquid copper into the interstices between solid particles was occurred at both cases. Therefore, the showing of the different dimensional changes in the compacts in spite of same chemical composition is due to more the alloying of copper into iron powder than the penetration of liquid copper into the interstices between solid particles.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.812-813
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• 2006

Dimensional change of compact made from (Fe-Cu) prealloyed powder and copper powder compared to that of compact made from iron-copper elemental powder. The compact made from the prealloyed powder with a copper content of 7.18mass% which is nearly equal to its solution limit and copper powder showed only the large contraction in spite of penetration of liquid copper into grain boundary of the prealloyed powder. But the compact made from iron-copper elemental powder showed the large expansion in spite of same chemical composition with former case.

• Journal of the Korean Electrochemical Society
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• v.10 no.3
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• pp.175-178
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• 2007

Pure iron, Fe-0.4, and 1.2 wt.%Cu alloys were examined by conducting the electrochemical techniques in the weakly alkaline solution, pH9, controlled by $Ca(OH)_2$, solution added with 0.02M NaCl. The $R_P$ measured from ac impedance, selected 10 kHz and 10mHz, in weakly alkaline solutions containing chloride ions indicated that the addition of copper up to 1.2wt.% into the pure iron significantly improved the pitting resistance of iron. In contrast to alloy, the pure iron showed the rapid pitting occurrences in drying period. During the drying period, the corrosion potential of pure iron was shifted to less noble value, pitting initiation.

• Journal of the Korean Society for Heat Treatment
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• v.25 no.1
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• pp.22-26
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• 2012

An influence of the addition of copper (0.5, 1.0 and 1.5 mass% Cu) on the microstructure and mechanical properties of high purity iron (99.998 mass%) was characterized. The microstructure and microhardness of high-purity iron based samples, which were rolled at room temperature and subsequently annealed, were investigated in this work. The microstructure of the samples has been observed by electron back scattering diffraction (EBSD) and the mechanical properties have been studied by using micro-Vickers hardness test. The results of microstructural observation showed that deformation band was formed in high purity iron by rolling at room temperature, and it was recovered by annealing up to about 900 K. The microhardness results showed that the softening of high-purity iron occurred by annealing up to about 900 K, while the hardness of iron added with about 0.5-1.5 mass% copper was kept over 100 Hv and at the early time of annealing reached a maximum. The hardness of iron added with a small amount of copper may be attributed to precipitation hardening as well as solution hardening. The orientation of crystal in recrystallized grain was almost same as that of deformed grain.

• Composites Research
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• v.36 no.4
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• pp.241-245
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• 2023

Aluminum (Al) and copper(Cu) are non-ferrous alloys with excellent electrical and thermal conductivity but have relatively lower mechanical properties than iron alloys. Stainless steel(STS), an iron alloy, is a high-strength industrial material due to its excellent mechanical properties and corrosion resistance compared to non-ferrous Al and Cu. In this research combined Al, Cu, and STS to fabricate as a functionally graded material (FGM) through a powder metallurgical process. The produced FGM exhibited lightweight and excellent surface hardness compared to copper and iron alloys and also showed higher thermal conductivity than single Al and STS materials.

• Conservation Science in Museum
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• v.1
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• pp.15-26
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• 1999

More than 200 objects selected for the newly-opened Kimhae National Museum were treated for conservation. The objects which represent ancient Kaya culture, were mainly composed of metallic such as gilt bronze, silver, copper alloy and iron. The corrosion products on gilt bronze and copper alloy objects were preserved or removed according to their stability. Minimum treatment was done for preserving the original state of the objects. For silver objects and iron objects with silver-plate decorations, silver surfaces were revealed after treatment of corrosion products and treatments to prevent corrosion of silver and iron were done emphatically. For iron objects, which were stabilized, the original shape of objects was restored and acrylic coating was applied to prevent further corrosion. For the objects which were being corroded, 2-step de-chloride treatments were undertaken. The first step was immersing the objects in a solution of 0.3M sodium hydroxide and the second was the pressure de-chloride treatment using borax-distilled water. The main purpose of those treatments was to get rid of the causes of corrosion. Besides, conservation treatments for potteries, making of special mounting board for exhibition and amendment of various modeling were done too.

• Journal of Powder Materials
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• v.25 no.1
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• pp.19-24
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• 2018

Cu-Fe alloys (CFAs) are much anticipated for use in electrical contacts, magnetic recorders, and sensors. The low cost of Fe has inspired the investigation of these alloys as possible replacements for high-cost Cu-Nb and Cu-Ag alloys. Here, alloys of Cu and Fe having compositions of $Cu_{100-x}Fe_x$ (x = 10, 30, and 50 wt.%) are prepared by gas atomization and characterized microstructurally and structurally based on composition and powder size with scanning electron microscopy (SEM) and X-ray diffraction (XRD). Grain sizes and Fe-rich particle sizes are measured and relationships among composition, powder size, and grain size are established. Same-sized powders of different compositions yield different microstructures, as do differently sized powders of equal composition. No atomic-level alloying is observed in the CFAs under the experimental conditions.

• Journal of Powder Materials
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• v.27 no.6
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• pp.449-457
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• 2020

Iron and copper are practically immiscible in the equilibrium state, even though their atomic radii are similar. As non-equilibrium solid solutions, the metastable Fe-Cu alloys can be synthesized using special methods, such as rapid quenching, vapor deposition, sputtering, ion-beam mixing, and mechanical alloying. The complexity of these methods (multiple steps, low productivity, high cost, and non-eco-friendliness) is a hinderance for their industrial applications. Electrical explosion of wire (EEW) is a well-known and effective method for the synthesis of metallic and alloy nanoparticles, and fabrication using the EEW is a simple and economic process. Therefore, it can be potentially employed to circumvent this problem. In this work, we propose the synthesis of Fe-Cu nanoparticles using EEW in a suitable solution. The powder shape, size distribution, and alloying state are analyzed and discussed according to the conditions of the EEW.

• Journal of the Korean Society for Heat Treatment
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• v.1 no.1
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• pp.13-23
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• 1988

The hardenability of alloyed ductile cast irons was studied for 54 different alloy compositions obtained from eight commercial and laboratory foundries. The alloying elements investigated for their effects on hardenability were Si(2.0 to 3.0%), Mn(0.0 to 0.8%), Mo(0.0 to 0.6%), Cu(0.0 to 1.5%), and Ni(0.0 to 1.5%). Two hardenability criteria, a first-pearlite hardenability criterion and a half-hard hardenability criterion, were used to determine hardenability of ductile irons. Prediction models for each hardenability criterion were developed by multiple regression analysis and were well agreed with previous experimental results. Molybdenum was the most potent hardenability promoting element followed by manganese, copper and nickel ; silicon had little effect on hardenability and reduced the hardenability as silicon content increased. When alloying elements were presented in combination, strong synergistic effects on the hardenability were observed especially between molybdenum, copper and nickel. The hardenability of ductile iron was strongly influenced by austenitizing temperature. Increasing austenitizing temperature up to $955^{\circ}C$, hardenability increased gradually but decreasing rate and then decreased as temperature increased above $955^{\circ}C$. Unless reducing segregation by very long-time annealing treatment, the hardenability of ductile iron was not significantly influenced by segregation of alloying elements.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.5
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• pp.536-541
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• 2015

Copper has been used extensively as an electric wire or as a base material in various types of machineries owing to its good electrical and thermal conductivity and good fabricating property, as well as its good corrosion resistance compared to iron. Furthermore, the copper-nickel alloy has significant corrosion resistance in severely corrosive environments. Although, cupro-nickel alloy shows better corrosion resistance than the brass and bronze series, this alloy also corroded in severely corrosive environments, including aggressive chloride ions, dissolved oxygen, and condition of fast flowing seawater. In this study, and annealing treatment at various annealing temperatures was carried out on the cupro-nickel (Cu-10%Ni) alloy, and the effects of annealing were investigated using electrochemical methods, such as measuring the polarization and impedance behaviors under flowing seawater conditions. The corrosion resistance increased by annealing compared to non heat treatment in the absence of flowing seawater. In particular, the sample annealed at $200^{\circ}C$ exhibited the best corrosion resistance. The impedance in the presence of flowing seawater showed higher values than in the absence of flowing seawater. Furthermore, the highest impedances was observed in the sample annealed at $800^{\circ}C$, irrespective of the present of flowing seawater. Consequently, the corrosion resistance of cupro-nickel (Cu-10%Ni) alloy in a severely corrosive environment can be improved somewhat by annealing.