Journal of Powder Materials

Pt and Polymer Electrolyte Membrane Fuel Cell: Hye-Sook Joo, Jung-Yeul Yun, Han-Shin Choi; J Korean Powder Metall Inst. 2011;18(1):1-13.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.001

143 View
6 Download
3 Citations

PDF

Citations

Citations to this article as recorded by

Synthesis of Platinum Nanoparticles by Liquid Phase Reduction
Jin-Ho Lee, Se-Hoon Kim, Jin-Woo Kim, Min-Ha Lee, Young-Do Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(1): 60. CrossRef
Shape Control of Platinum Nanoparticles Using a Metal Salt
Seoung Yeul Kwak, Jin Ho Lee, Jin Woo Kim, Taek Kyun Jung, Young Do Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(6): 393. CrossRef
Luminescent Characteristics of CdSe Quantum Dot Phosphor Depending on Se Precursor Ratio
Nu Si A Eom, Taek-Soo Kim, Yong-Ho Choa, Bum Sung Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(6): 442. CrossRef

Synthesis of TiO₂ Nanotubes and Their Sensitivity for Toluene Gas: H.Y. Yue, S. Huang, E.J. Guo, L.P. Wang, F.W. Kang, Z.M. Yu, Y.K. Guo, F.L. Sun; J Korean Powder Metall Inst. 2011;18(1):14-17.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.014

83 View
0 Download
2 Citations

Abstract PDF

TiO_2 nanopowders with anatase structure were firstly prepared by controlling the pH value of a precursor solution without any heat-treatment at room temperature. The prepared TiO_2 nanopowders were hydrothermally treated in 10M NaOH solution at 170°C. Then, the samples were washed in DI water or 0.1M HCl. The TiO_2 nanotubes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The gas sensitivity of TiO_2 nanotubes for toluene gas was also investigated. The results show that TiO_2 nanotubes can be prepared by hydrothermal treatment. The morphology of TiO_2 nanotubes prepared by 0.1M HCl washing is destroyed to some extent. TiO_2 nanotubes with DI water washing show better sensitivity than that with 0.1M HCl washing.

Citations

Citations to this article as recorded by

Synthesis and Characterization of Nickel Nanowires by an Anodic Aluminum Oxide Template-Based Electrodeposition
Hyo-Ryoung Lim, Yong-Ho Choa, Young-In Lee
Journal of Korean Powder Metallurgy Institute.2015; 22(3): 216. CrossRef
Synthesis and Characterization of Cu Nanowires Using Anodic Alumina Template Based Electrochemical Deposition Method
Young-In Lee, Yong-Ho Choa
Journal of Korean Powder Metallurgy Institute.2012; 19(5): 367. CrossRef

The Coercivity Enhancement of (Nd,Dy)-Fe-B Sintered Magnet by Microstructure Control: Jin-Woo Kim, Se-Hoon Kim, Young-Do Kim; J Korean Powder Metall Inst. 2011;18(1):18-23.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.018

139 View
1 Download
3 Citations

Abstract PDF

Sintered Nd-Fe-B magnets are widely used in many fields such as motors, generators, actuators, microwaves and so on due to their excellent magnetic properties. Many researchers have shown that the Nd-rich phase was essentially important for high magnet properties. In this study, we focused on controlling of the Nd-rich phase to enhance magnetic properties by the cyclic sintering process. Nd-Fe-B based sintered magnets were prepared by isothermal sintering and cyclic sintering processes. Magnetic properties and microstructure of the magnets were investigated. The coercivity was enhanced from 21.2 kOe to 23.27 kOe after 10 cycles of the sintering. The Nd-rich phase was effectively penetrated into the grain boundary between the Nd_2Fe_14B grains by the cyclic sintering.

Citations

Citations to this article as recorded by

Effect of cyclic sintering process for NdFeB magnet on microstructure and magnetic properties
Jin Woo Kim, Sun Yong Song, Young Do Kim
Journal of Alloys and Compounds.2012; 540: 141. CrossRef
Transmission electron microscopy studies of sintered Nd-Fe-B magnets prepared by cyclic sintering
Jin Woo Kim, Se Hoon Kim, Sun Yong Song, Young Do Kim
Journal of Applied Physics.2012;[Epub] CrossRef
Magnetic Properties and Sintering Behavior of (Nd,Dy)-Fe-B Permanent Magnet by Spark Plasma Sintering
Sun-Yong Song, Jin-Woo Kim, Se-Hoon Kim, Young-Do Kim
Journal of Korean Powder Metallurgy Institute.2012; 19(2): 105. CrossRef

Effect of Cu Content on Microstructural and Magnetic Properties of a Nd-Fe-B Strip Cast: Song-E Park, Tae-Hoon Kim, Seong-Rae Lee, Dong-Hwan Kim, Seok NamKung, Tae-Suk Jang; J Korean Powder Metall Inst. 2011;18(1):24-28.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.024

137 View
0 Download
2 Citations

Abstract PDF

Effect of Cu content on microstructural and magnetic properties of a (Nd_26.06,Dy_6.51)Fe_bal. Cu_xB_0.97(wt.%), (x = 0.2, 0.3, 0.4, 0.5) strip-cast was studied. The average inter-lamellar spacing in the free surface and wheel side of the strip cast increased as the Cu content increases. The grain uniformity, the grain alignment, and (00L) texture of the strip cast increased with Cu contents up to 0.4 wt.%. These microstructural changes were attributed to the decrease of the effective cooling rate of the melted alloy caused by the decrease of the melting temperature of resulting from Cu addition. Coercivity and remanence were increased because of the grain alignment and (00L) texture improvement with Cu contents up to 0.4 wt.%.

Citations

Citations to this article as recorded by

Microstructure and magnetic properties of (Nd,Dy)FeB and (Nd,Pr)FeB strips
Seung-Yeon Park, Jin-Ho Kim, Kyoung-Mook Lim, Sung-Yong Ahn, Kang Ryong Choi, Chul-Sung Kim
Journal of the Korean Physical Society.2015; 66(11): 1755. CrossRef
Effects of the cooling rate on the microstructure of Nd-Fe-B alloys fabricated by strip casting
Kyoung-Mook Lim, Seung-Yeon Park, Sung-Yong Ahn, Chul-Sung Kim
Journal of the Korean Physical Society.2013; 63(6): 1203. CrossRef

Magnetic Properties of (Nd, Dy)-Fe-B Sintered Magnets Mixed with Dy Compounds: S. NamKung, M.W. Lee, I.S. Cho, Y.D. Park, T.H. Lim, S.R. Lee, T.S. Jang; J Korean Powder Metall Inst. 2011;18(1):29-34.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.029

62 View
0 Download

Abstract PDF: In order to increase the coercivity of (Nd, Dy)-Fe-B sintered magnets without much reduction of remanence, small amount of Dy compounds such as Dy_2O_3 and DyF_3 was mixed with (Nd, Dy)-Fe-B powder. After mixing, the coercivity of (Nd, Dy)-Fe-B sintered magnets apparently increased with the increase of Dy compound in the mixture. Addition of DyF_3 was more effective than Dy_2O_3 for the improvement of coercivity. Reduction of the remanence by the addition of Dy compound, however, was larger than expected mostly due to unresolved coarse Dy compound in the magnet. EPMA analysis revealed that Dy was diffused throughout the grains in the magnet mixed with DyF_3 whereas Dy was rather concentrated around grain boundaries in the magnet mixed with Dy_2O_3.

Characteristics of Spodumene Powders Synthesized by Polyvinyl Alcohol Solution Technique: Sang-Jin Lee, Ji-Eun Park; J Korean Powder Metall Inst. 2011;18(1):35-40.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.035

63 View
0 Download
2 Citations

Abstract PDF

LAS-system ceramic powder, spodumene (Li_2OcdotAl_2O_3cdot4SiO_2), was successfully synthesized by a chemical solution technique employing PVA(polyvinyl alcohol) as an organic carrier. The PVA content affected the microstructure of porous precursor gels and the crystalline development. The optimum PVA content contributed to homogeneous distribution of metal ions in the precursor gel and it resulted in the synthesis of glass free beta-spodumene powder having a specific surface area of 7.57;m2/g. The agglomerated beta-spodumene powders were also enough soft to grind to fine powders by a simple ball milling process. The microstructures of the densified powder compacts were strongly dependant on the minor phases of spodumene solid solution and amount of liquid phase, which were formed from the inhomogeneous precursors.

Citations

Citations to this article as recorded by

Pulverization and Densification Behavior of YAG Powder Synthesized by PVA Polymer Solution Method
Hyun-Ho Im, Sang-Jin Lee
Korean Journal of Materials Research.2020; 30(11): 573. CrossRef
Synthesis of YAG:Ce3+Phosphor Powders by Polymer Solution Route and Alumina Seed Application
Yong-Hyeon Kim, Sang-Jin Lee
Journal of Korean Powder Metallurgy Institute.2013; 20(1): 37. CrossRef

Microstructure and PTCR Characteristics of Porous BaTiO₃-based Ceramics Prepared by Adding Carbon Black: Ki-Ju Lee, Dongxu Tang, Won-Seung Cho; J Korean Powder Metall Inst. 2011;18(1):41-48.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.041

82 View
0 Download

Abstract PDF: As a pore precursor, carbon black with different content of 0 to 60 vol% were added to (Ba,Sr)TiO_3 powder. Porous (Ba,Sr)TiO_3 ceramics were prepared by pressureless sintering at 1350°C for 1h under air. Effects of carbon black content on the microstructure and PTCR characteristics of porous (Ba,Sr)TiO_3 ceramics were investigated. The porosity of porous (Ba,Sr)TiO_3 ceramics increased from 6.97% to 18.22% and the grain size slightly decreased from 7.51;µm to 5.96;µm with increasing carbon black contents. PTCR jump of the (Ba,Sr)TiO_3 ceramics prepared by adding carbon black was more than 105, and slightly increased with increasing carbon black. The PTCR jump in the (Ba,Sr)TiO_3 ceramics prepared by adding 40 vol% carbon black showed an excellent value of 9.68times105, which was above two times higher than that in (Ba,Sr)TiO_3 ceramics. These results correspond with Heywang model for the explanation of PTCR effect in (Ba,Sr)TiO_3 ceramics. It was considered that carbon black is an effective additive for preparing porous BaTiO_3 based ceramics. It is believed that newly prepared (Ba,Sr)TiO_3 cermics can be used for PTC thermistor.

Fabrication and Growth of Ni Nanowires by using Anodic Aluminum Oxide(AAO) Template via Electrochemical Deposition: Seong-Ju Sim, Kwon-Koo Cho, Yoo-Young Kim; J Korean Powder Metall Inst. 2011;18(1):49-55.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.049

86 View
1 Download
4 Citations

Abstract PDF

Ni nanowires were fabricated using anodic aluminum oxide (AAO) membrane as a template by electrochemical deposition. The nanowires were formed within the walls of AAO template with 200 nm in pore diameter. After researching proper voltage and temperature for electrochemical deposition, the length of Ni nanowires was controlled by deposition time and the supply of electrolyte. The morphology and microstructure of Ni nanowires were investigated by field emission scanning electron microscope (FE-SE), X-ray diffraction (XRD) and transmission electron microscope (TEM).

Citations

Citations to this article as recorded by

Electrocrystallization of Metals in Channels of Porous Films of Anodic Aluminum Oxide: The Real Template Structure and the Quantitative Model of Electrodeposition
A. A. Noyan, I. V. Kolesnik, A. P. Leont’ev, K. S. Napol’skii
Russian Journal of Electrochemistry.2023; 59(7): 489. CrossRef
Electrocrystallization of Metals in Channels of Porous Films of Anodic Aluminum Oxide: The Real Template Structure and the Quantitative Model of Electrodeposition
A. A. Noyan, I. V. Kolesnik, A. P. Leont’ev, K. S. Napol’skii
Электрохимия.2023; 59(7): 378. CrossRef
Synthesis and Characterization of Nickel Nanowires by an Anodic Aluminum Oxide Template-Based Electrodeposition
Hyo-Ryoung Lim, Yong-Ho Choa, Young-In Lee
Journal of Korean Powder Metallurgy Institute.2015; 22(3): 216. CrossRef
Synthesis and Characterization of Cu Nanowires Using Anodic Alumina Template Based Electrochemical Deposition Method
Young-In Lee, Yong-Ho Choa
Journal of Korean Powder Metallurgy Institute.2012; 19(5): 367. CrossRef

Fabrication and Growth Behavior of TiO₂ Nanotube Arrays by Anodic Oxidation Method: Seon-Min Kim, Ki-Won Kim, Kwang-Sun Ryu, Yoo-Young Kim, Kwon-Koo Cho; J Korean Powder Metall Inst. 2011;18(1):56-63.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.056

65 View
0 Download

Abstract PDF: Recently, TiO_2 nanotubes have considerably researched because of their novel application about photocatalysis, dye-sensitized solar cells (DSSCs), lithium ion battery, etc. In this work, self-standing TiO_2 nanotube arrays were fabricated by anodic oxidation method using pure Ti foil as a working electrode in ethylene glycole with 0.3M NH_4F + 2%H_2O. Growth behavior of TiO_2 nanotube arrays was compared according to temperature, voltage and time. The morphology, structure and crystalline of anodized TiO_2 nanotube arrays were observed by FE-SEM (field emission scanning electron microscope) and XRD (X-ray diffraction).

Evaluation of Mechanical Properties by Using Instrumented Indentation Testing for Resistance Spot Welds: Chul-Young Choi, Jun-Ki Kim, Jae-Keun Hong, Jong-Taek Yeom, Yeong-Do Park; J Korean Powder Metall Inst. 2011;18(1):64-72.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.064

88 View
1 Download
1 Citations

Abstract PDF

Nondestructive instrumented indentation test is the method to evaluate the mechanical properties by analyzing load - displacement curve when forming indentation on the surface of the specimen within hundreds of micro-indentation depth. Resistance spot welded samples are known to difficult to measure the local mechanical properties due to the combination of microstructural changes with heat input. Particularly, more difficulties arise to evaluate local mechanical properties of resistance spot welds because of having narrow HAZ, as well as dramatic changed in microstructure and hardness properties across the welds. In this study, evaluation of the local mechanical properties of resistance spot welds was carried out using the characterization of Instrumented Indentation testing. Resistance spot welding were performed for 590MPa DP (Dual Phase) steels and 780MPa TRIP (Transformation Induced Plasticity) steels following ISO 18278-2 condition. Mechanical properties of base metal using tensile test and Instrumented Indentation test showed similar results. Also it is possible to measure local mechanical properties of the center of fusion zone, edge of fusion zone, HAZ and base metal regions by using instrumented indentation test. Therefore, measurement of local mechanical properties using instrumented indentation test is efficient, reliable and relatively simple technique to evaluate the tensile strength, yield strength and hardening exponent.

Citations

Citations to this article as recorded by

Vacuum brazing of dissimilar tubular component of AA2219 and AISI 304 by a low melting Al-18Ag-20Cu-5Si-0.2Zn braze alloy
Srinivas V., Amit Kumar Singh, Gopala Krishna V., Madhusudhan Reddy G.
Journal of Materials Processing Technology.2018; 252: 1. CrossRef

Synthesis of Yttrium Oxide Nanowire by Hydrothermal Method: Kyung-Ki Kim, Yong-Jin Kim, Jung-Ho Ahn; J Korean Powder Metall Inst. 2011;18(1):73-77.; DOI: https://doi.org/10.4150/KPMI.2011.18.1.073

101 View
0 Download
1 Citations

Abstract PDF

Y(OH)_3 nanowires were synthesized by a hydrothermal reaction of metallic Y with aqueous solution of LiOH. The morphology and the size of the nanowires changed with varying the volume of the LiOH solution inside the autoclave. Y(OH)_3 nanowires transformed to Y_2O_3 by a subsequent heat-treatment without morphological change. By a proper control of hydrothermal reaction parameter and heat-treatment, the yield of pure Y_2O_3 nanowires up to 97% was attained.

Citations

Citations to this article as recorded by

Synthesis and Characterization of SnO2-CoO/carbon-coated CoO Core/shell Nanowire Composites
Yu-Jin Lee, Bon-Ryul Koo, Hyo-Jin Ahn
Journal of Korean Powder Metallurgy Institute.2014; 21(5): 360. CrossRef

Previous issues