Journal of Powder Materials

Fabrication of Bulk Metallic Glass Alloys by Warm Processing of Amorphous Powders: J Korean Powder Metall Inst. 2004;11(3):193-201.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.193

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Effect of Reaction Factors on the Fabrication of Nano-Sized Ni-ferrite Powder by Spray Pyrolysis Process: J Korean Powder Metall Inst. 2004;11(3):202-209.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.202

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Abstract PDF: In this study, nano-sized powder of Ni-ferrite was fabricated by spray pyrolysis process using the Fe-Ni complex waste acid solution generated during the shadow mask processing. The average particle size of the produced powder was below 100 nm. The effects of the reaction temperature, the inlet speed of solution and the air pressure on the properties of powder were studied. As the reaction temperature increased from 800°C to 1100°C, the average particle size of the powder increased from 40 nm to 100 nm, the fraction of the Ni-ferrite phase was also on the rise, and the surface area of the powder was greatly reduced. As the inlet speed of solution increased from 2 cc/min. to 10 cc/min., the average particle size of the powder greatly increased, and the fraction of the Ni-ferrite phase was on the rise. As the inlet speed of solution increased to 100 cc/min., the average particle size of the powder decreased slightly and the distribution of the particle size appeared more irregular. Along with the increase of the inlet speed of solution more than 10 cc/min., the fraction of the Ni-ferrite phase was decreased. As the air pressure increased up to 1 kg/cm2, the average particle size of the powder and the fraction of the Ni-ferrite phase was almost constant. In case of 3 kg/cm2 air pressure, the average particle size of the powder and the fraction of the Ni-ferrite phase remarkably decreased.

Effect of Atmospheric Gas on the Size and Distribution of Cu Nano Powders Synthesized by Pulsed Wire Evaporation Method: A. Y.; J Korean Powder Metall Inst. 2004;11(3):210-216.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.210

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Abstract PDF: The possibility to decrease agglomeration of Cu nano powders and their separation during pulsed wire evaporation (PWE) process was investigated by controlling the working gas system, i.e., the design of the gas path, the type and pressure of the atmospheric gas. As a result, it was possible to choose the optimal design of the gas path providing large specific surface area and high degree of separation of the synthesized Cu nano powders. It was also shown that an Ar+10∼50N_2 mixture can be used in production of Cu nano powders, which do not react with nitrogen.

Preparation of Spherical Nickel Powder by Hydrothemal Process: J Korean Powder Metall Inst. 2004;11(3):217-223.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.217

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Submicron nickel powders were prepared from aqueous solution under hydrothermal condition. The experimental conditions including the types of protective agents, concentration of the solution and the pH were studied in detail. Starting concentration of nickel ion is a dominant factor affecting particle size. It was shown that the subsequent addition of Poly Vinyl Pyrrolidone(PVP) and Sodium Dodecyle Sulfate(SDS) can help to disperse the nickel powder. X-ray diffraction and SEM were employed to characterize the products.

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Recovery Of Nickel From Spent Nickel-Cadmium Batteries Using A Direct Reduction Process
D.J. Shin, S.-H. Joo, J.-P. Wang, S.-M. Shin
Archives of Metallurgy and Materials.2015; 60(2): 1365. CrossRef

Characteristics of Nickel-Diamond Composite Powders by Electroless Nickel Plating: Tri Hoang; J Korean Powder Metall Inst. 2004;11(3):224-232.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.224

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Ni-diamond composite powders with nickel layer of round-top type on the surface of synthetic diamond (140/170 mesh) were prepared by the electroless plating method (EN) with semi-batch reactor. The effects of nickel concentration, feeding rates of reductant, temperature, reaction time and stirring speeds on the weight percentage and morphology of deposited Ni, mean particle size and specific surface area of the composite powders were investigated by Atomic Adsortion Spectrometer, SEM-EDX, PSA and BET. It was found that nucleated Ni-P islands, acted as catalytic sites for further deposition and grown into these relatively thick layers with nodule-type on the surface of diamond by a lateral growth mechanism. The weight percentage of Ni in the composite powder increased with reaction time, feeding rate of reductant and temperature, but decreased with stirring speed. The weight percentage of Ni in Ni-diamond composite powder was 55% at 150 min., 200 rpm and 70°C .

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Thermal Properties of Diamond Aligned Electroless Ni Plating Layer/Oxygen Free Cu Substrates
Da-Woon Jeong, Song-Yi Kim, Kyoung-Tae Park, Seok-Jun Seo, Taek Soo Kim, Bum Sung Kim
Journal of Korean Powder Metallurgy Institute.2015; 22(2): 134. CrossRef

Consolidation of Rapidly Solidified Al-20 wt％ Si Alloy Powders Using Equal Channel Angular Pressing: J Korean Powder Metall Inst. 2004;11(3):233-241.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.233

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In this study, bottom-up type powder processing and top-down type SPD (severe plastic deformation) approaches were combined in order to achieve both full density and grain refinement of Al-20 wt% Si powders without grain growth, which was considered as a bottle neck of the bottom-up method using the conventional powder metallurgy of compaction and sintering. ECAP (Equal channel angular pressing), one of the most promising method in SPD, was used for the powder consolidation. The powder ECAP processing with 1, 2, 4 and 8 passes was conducted for 100°C and 200°C It was found by microhardness, compression tests and micro-structure characterization that high mechanical strength could be achieved effectively as a result of the well bonded powder contact surface during ECAP process. The SPD processing of powders is a viable method to achieve both fully density and nanostructured materials.

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Ultrafine Grained Cu-diamond Composites using High Pressure Torsion
Eun-Yoo Yoon, Dong-Jun Lee, Taek-Soo Kim, Hyoung-Seop Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(3): 204. CrossRef
Analysis of Densification Behavior of Nano Cu Powders during Cold Isostatic Pressing

Journal of Korean Powder Metallurgy Institute.2004; 11(4): 341. CrossRef

Synthesis of FePt Nanoparticles by Chemical Reduction Process: J Korean Powder Metall Inst. 2004;11(3):242-246.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.242

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Abstract PDF: FePt nanoparticles for high-density magnetic recording media were synthesized by the simultaneous chemical reduction of Fe(acac) _2 and Pt(acac) _2 with 1,2-hexadecanediol as the reducing reagent. TEM images showed that the shape of as-synthesized FePt nanoparticle was spherical and average particle size was 3 nm. Also, SAD pattern showed that crystal structure was disordered FCC (face centered cubic). These FCC structured nanoparticles were transformed FCT (face centered tetragonal) structure by annealing at 550°C for 30 min in Ar atmosphere. XRD analysis revealed that as-synthesized FePt nanoparticles were transformed from disordered FCC to ordered FCT. Finally, the coercivity of 2 kOe for FePt nanoparticles with FCT structure was obtained by VSM measurement.

Fabrication of Composite Powders by Mechanical Alloying of Magnetite-M (M = Ti, Al) Systems: J Korean Powder Metall Inst. 2004;11(3):247-252.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.247

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Abstract PDF: Recently, it has been found that mechanical alloying (MA) facilitates the nanocomposites formation of metal-metal oxide systems through solid-state reduction during ball milling. In this work, we studied the MA effect of Fe_3O_4-M (M = Al, Ti) systems, where pure metals are used as reducing agents. It is found that composite powders in which Al_2O_3 and TiO_2 are dispersed in alpha-Fe matrix with nano-sized grains are obtained by mechanical alloying of Fe_3O_4 with Al and Ti for 25 and 75 hours, respectively. It is suggested that the large negative heat associated with the chemical reduction of magnetite by aluminum is responsible for the shorter MA time for composite powder formation in Fe_3O_4-Al system. X-ray diffraction results show that the reduction of magnetite by Al and Ti if a relatively simple reaction, involving one intermediate phase of FeAl_2O_4 or Fe_3Ti_3O_10. The average grain size of alpha-Fe in Fe-TiO_2 composite powders is in the range of 30 nm. From magnetic measurement, we can also obtain indirect information about the details of the solid-state reduction process during MA.

Synthesis of W₁₈O₄₉ Phase by Carbothermal Reduction of Tungsten Oxide and its Field Emission Characteristics: Hyo-Seung Yang, Hoon Park, Hyoung-chul Kim, Jae-Pyoung Ahn, Moo-Young Huh, Jong-Ku Park; J Korean Powder Metall Inst. 2004;11(3):253-258.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.253

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Abstract PDF: We report a carbothermal reduction process for massive synthesis of monolithic W_18O_49 phase from tungsten oxide in the presence of carbon source. Carbon black powder was used as a carbon source and added to WO_3 by 40 weight percent. Bundles of W_18O_49 rods were formed over the temperature range of 800°C°C to 900°C. Pure W_18O_49 bundles could be separated from the mixture of W_18O_49 and residual carbon black powder. Field emission character of W_18O_49 phase was determined using the extracted W_18O_49 rods. Flat lamp fabricated from the W_18O_49 rods showed the turn-on field of 9.3 V/µm.

Microstructure and Mechanical Properties of (SiC)_p/Al Composite Fabricated by a Powder-in Sheath Rolling Method: J Korean Powder Metall Inst. 2004;11(3):259-264.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.259

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Aluminum based metal matrix composite reinforced with SiC particles was fabricated by the powder-in sheath rolling method. A stainless steel tube with outer diameter of 12 mm and wall thickness of 1mm was used as a sheath. Mixture of aluminum powder and SiC particles of which volume content was varied from 5 to 20vol.% was filled in the tube by tap filling and then rolled to 75% reduction at ambient temperature. The rolled specimen was sintered at 560°C for 0.5hr. The tensile strength of the (SiC)_p/Al composite increased with the volume content of SiC particles, and at 20vol.% it reached a maximum of 100㎫ which is 1.6 times higher than unreinforced material. The elongation decreased with the volume content of Al_2O_3 particles. The mechanical properties of the (SiC)_p/Al composite fabricated by the powder-in sheath rolling is compared with that of (Al_2O_3)_p/Al composite by the same process.ess.

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Microstructure and Mechanical Properties of 3vol%CNT Reinforced Cu Matrix Composite Fabricated by a Powder in Sheath Rolling Method
Seong-Hee Lee
Korean Journal of Materials Research.2020; 30(3): 149. CrossRef
Microstructure and Mechanical Properties of CNT/Al Composite Fabricated by a Powder-in-Sheath Rolling Method utilizing Copper Tube as a Sheath
Seong-Hee Lee
Journal of Korean Powder Metallurgy Institute.2014; 21(5): 343. CrossRef
Fabrication and Evaluation of Carbon Nanotube Reinforced Al Matrix Composite by a Powder-in-sheath Rolling Method
Seong-Hee Lee, Dongmin Hong
Journal of Korean Powder Metallurgy Institute.2014; 21(1): 50. CrossRef
Fabrication and Evaluation of 5 vol%CNT/Al Composite Material by a Powder in Sheath Rolling Method
동민 홍, 성희 이, 우진 김
Korean Journal of Materials Research.2013; 23(11): 607~612. CrossRef

Technology of Titanium Powder Materials: J Korean Powder Metall Inst. 2004;11(3):265-270.; DOI: https://doi.org/10.4150/KPMI.2004.11.3.265

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Deoxidation of Titanium Scrap by Calciothermic Reduction
Moo-Won Yoon, Ho-Sang Sohn
Journal of the Korean Institute of Resources Recycling.2013; 22(6): 41. CrossRef

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