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Microstructural Characterization of Gas Atomized Copper-Iron Alloys with Composition and Powder Size
Abbas, Sardar Farhat,Kim, Taek-Soo The Korean Powder Metallurgy Institute 2018 한국분말재료학회지 (KPMI) Vol.25 No.1
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.
Sardar Farhat Abbas,Taek-Soo Kim,Bum-Sung Kim 대한금속·재료학회 2018 METALS AND MATERIALS International Vol.24 No.4
With the increase in global demand for highly functionalized materials, there is continued interest in exploiting the materialproperties of metals either individually or in the form of alloys. Copper–iron alloy is considered unique with its remarkablecombination of strength and high electrical conductivity. Due to the low cost of iron, this alloy is expected to replace alloyslike Cu–Ag and Cu–Nb. In order to explore the microstructural features, copper–iron alloy with three Different compositions(10, 30, and 50 at.% Fe) were prepared by a gas atomization process. A detailed microstructural characterization was performedusing scanning electron microscopy, X-ray diff raction, and electron backscattered diff raction. Spark plasma sinteringwas used to sinter the powders to evaluate their electrical conductivities. The mechanism of the microstructure formation isalso discussed in detail. As the Fe content increases, the Fe-rich phase changes its shape from spherical to irregular with aconcomitant sharp decrease in the electrical conductivity of the alloy.
사다르 파라트 아바스,이상현,이빈,김범성,김택수,Abbas, Sardar Farhat,lee, Sang-Hyun,Lee, Bin,Kim, Bum-Sung,Kim, Taek-Soo 한국분말야금학회 2018 한국분말재료학회지 (KPMI) Vol.25 No.2
Rare earth elements (REEs) are considered to be vital to modern industry due to their important roles in applications such as permanent magnets, automobile production, displays, and many more. The imbalance between demand and supply of REEs can be solved by recycling processes. Regarding the needs of industry and society, the International Organization for Standardization, Technical Committee 298 (ISO/TC298) Rare Earths has been recently launched for developing international standards on rare earth elements. In accordance with the suggestion of its constituents, it is tentatively working to develop the appropriate standards under five working groups (WG) on terms and definitions (WG1), element recycling (WG2), environmental stewardship (WG3), packaging, labelling, marking, transport, and storage (WG4), and testing analysis (WG5). The scope and structure of ISO/TC298 on the topic of rare earths is discussed in this document.
ISO TC 298에서의 희토류 분야 표준화 현황과 우리나라의 전략 및 과제
엄누시아,사다르 아바스,무하마드 아닉,무하마드 자라르,이미혜,김범성,김택수,이빈,Eom, Nu Si A,Abbas, Sardar Farhat,Aneeq, Haq Muhammad,Zarar, Rasheed Mohammad,Lee, Mi Hye,Kim, Bum Sung,Kim, Taek-Soo,Lee, Bin 한국분말재료학회 (*구 분말야금학회) 2019 한국분말재료학회지 (KPMI) Vol.26 No.3
Since the ISO decided to deal with rare-earth elements at the $298^{th}$ Technical Committee (TC) in 2015, Korea has participated in four plenary meetings and proposed four standards as of June 2019. The status of ISO TC 298, the standards covered by the TC, and the standardization strategies of Korea are summarized. Korean delegations are actively engaged in WG2, which deals with recycling, proposing four standards for fostering the rare-earth recycling industry. However, the participation of domestic experts is still low compared with the increase in the number of working groups and the number of standards in TC 298. The aim of this article is to summarize the current status of ISO international standards related to rare-earth elements, to encourage relevant experts to participate in standardization, and to develop international standards that accurately reflect the realities of the industry.
Rizwan, Muhammad,Ali, Shafaqat,Qayyum, Muhammad Farooq,Ok, Yong Sik,Adrees, Muhammad,Ibrahim, Muhammad,Zia-ur-Rehman, Muhammad,Farid, Mujahid,Abbas, Farhat Elsevier 2017 Journal of hazardous materials Vol.322 No.1
<P><B>Abstract</B></P> <P>The concentrations of engineered metal and metal oxide nanoparticles (NPs) have increased in the environment due to increasing demand of NPs based products. This is causing a major concern for sustainable agriculture. This review presents the effects of NPs on agricultural crops at biochemical, physiological and molecular levels. Numerous studies showed that metal and metal oxide NPs affected the growth, yield and quality of important agricultural crops. The NPs altered mineral nutrition, photosynthesis and caused oxidative stress and induced genotoxicity in crops. The activities of antioxidant enzymes increased at low NPs toxicity while decreased at higher NPs toxicity in crops. Due to exposure of crop plants to NPs, the concentration of NPs increased in different plant parts including fruits and grains which could transfer to the food chain and pose a threat to human health. In conclusion, most of the NPs have both positive and negative effects on crops at physiological, morphological, biochemical and molecular levels. The effects of NPs on crop plants vary greatly with plant species, growth stages, growth conditions, method, dose, and duration of NPs exposure along with other factors. Further research orientation is also discussed in this review article.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Metal and metal oxide nanoparticles (NPs) are widely used worldwide. </LI> <LI> NPs has both positive and negative effects of crop plants. </LI> <LI> NPs toxicity decreased growth, biomass and yield of food crops. </LI> <LI> This review discussed the NPs effects and toxicity mechanisms in food crops. </LI> </UL> </P>