Cu-Mn compacts are fabricated by the pulsed current activated sintering method (PCAS) for sputtering target application. For fabricating the compacts, optimized sintering conditions such as the temperature, pulse ratio, pressure, and heating rate are controlled during the sintering process. The final sintering temperature and heating rate required to fabricate the target materials having high density are 700°C and 80°C/min, respectively. The heating directly progresses up to 700°C with a 3 min holding time. The sputtering target materials having high relative density of 100% are fabricated by employing a uniaxial pressure of 60 MPa and a sintering temperature of 700°C without any significant change in the grain size. Also, the shrinkage displacement of the Cu-Mn target materials considerably increases with an increase in the pressure at sintering temperatures up to 700°C.

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• Fabrication and Mechanical Property of Fe-20Cu-1C Compacts by SPS process with Different Heating Rate
  Jung-Han Ryu, Soo-Sik Shin, Byung-Rok Ryu, Kyung-Sik Kim, Jun-Ho Jang, Ik-Hyun Oh, Kap-Tae Kim, Hyun-Kuk Park
  Journal of Korean Powder Metallurgy Institute.2017; 24(4): 302.     CrossRef

A bulk-type Ta material is fabricated using the kinetic spray process and its microstructure and physical properties are investigated. Ta powder with an angular size in the range 9-37 μm (purity 99.95%) is sprayed on a Cu plate to form a coating layer. As a result, ~7 mm-sized bulk-type high-density material capable of being used as a sputter material is fabricated. In order to assess the physical properties of the thick coating layer at different locations, the coating material is observed at three different locations (surface, center, and interface). Furthermore, a vacuum heat treatment is applied to the coating material to reduce the variation of physical properties at different locations of the coating material and improve the density. OM, Vickers hardness test, SEM, XRD, and EBSD are implemented for analyzing the microstructure and physical properties. The fabricated Ta coating material produces porosity of 0.11~0.12%, hardness of 311~327 Hv, and minor variations at different locations. In addition, a decrease in the porosity and hardness is observed at different locations upon heat treatment.

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• Sintering Behavior and Microstructures of Tantalum and Tantalum-Tungsten Alloys Powders
  Youngmoo Kim, Sung Ho Yang, Seong Lee, Sung Ho Lee, Joon-Woong Noh
  Journal of Korean Powder Metallurgy Institute.2020; 27(5): 373.     CrossRef
• Manufacturing of Large-Scale Cold-Sprayed Ta Target Material and Its Sputtering Property
  Gi-Su Ham, Dong-Yeol Wi, Jun-Mo Yang, Kee-Ahn Lee
  Journal of Thermal Spray Technology.2019; 28(8): 1974.     CrossRef
• Mechanical properties of Mo-Nb-Si-B quaternary alloy fabricated by powder metallurgical method
  Jong Min Byun, Su-Ryong Bang, Se Hoon Kim, Won June Choi, Young Do Kim
  International Journal of Refractory Metals and Hard Materials.2017; 65: 14.     CrossRef

Niobium is one of the most important and rarest metals, and is used in the electronic and energy industries. However, it’s extremely high melting point and oxygen affinity limits the manufacture of Nb coating materials. Here, a Nb coating material is manufactured using a kinetic spray process followed by hot isotactic pressing to improve its properties. OM (optical microscope), XRD (X-ray diffraction), SEM (scanning electron microscopy), and Vickers hardness and EPMA (electron probe micro analyzer) tests are employed to investigate the macroscopic properties of the manufactured Nb materials. The powder used to manufacture the material has angular-shaped particles with an average particle size of 23.8 μm. The porosity and hardness of the manufactured Nb material are 0.18% and 221 Hv, respectively. Additional HIP is applied to the manufactured Nb material for 4 h under an Ar atmosphere after which the porosity decreases to 0.08% and the hardness increases to 253 Hv. Phase analysis after the HIP shows the presence of only pure Nb. The study also discusses the possibility of using the manufactured Nb material as a sputtering target.

The microstructural properties and electrical characteristics of sputtering films deposited with a Cu-Ga target are analyzed. The Cu-Ga target is prepared using the cold spray process and shows generally uniform composition distributions, as suggested by secondary ion mass spectrometer (SIMS) data. Characteristics of the sputtered Cu-Ga films are investigated at three positions (top, center and bottom) of the Cu-Ga target by X-ray diffraction (XRD), SIMS, 4-point probe and transmission electron microscopy (TEM) analysis methods. The results show that the Cu-Ga films are composed of hexagonal and unknown phases, and they have similar distributions of composition and resistivity at the top, center, and bottom regions of the Cu-Ga target. It demonstrates that these films have uniform properties regardless of the position on the Cu-Ga target. In conclusion, the cold spray process is expected to be a useful method for preparing sputter targets.

Powder injection molding (PIM), which combines the advantages of powder metallurgy and plastic injection molding technologies, has become one of the most efficient methods for the net-shape production of both metal and ceramic components. In this work, plasma display panel glass bodies are prepared by the PIM process. After sintering, the hot isostatic pressing (HIP) process is adopted for improving the density and mechanical properties of the PIMed glass bodies. The mechanical and thermal behaviors of the prepared specimens are analyzed through bending tests and dilatometric analysis, respectively. After HIPing, the flexural strength of the prepared glass body reaches up to 92.17 MPa, which is 1.273 and 2.178 times that of the fused glass body and PIMed bodies, respectively. Moreover, a thermal expansion coefficient of 7.816 × 10⁻⁶/°C is obtained, which coincides with that of the raw glass powder (7.5-8.0 × 10⁻⁶/°C), indicating that the glass body is fully densified after the HIP process.

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• Fabrication and characteristics of Li2TiO3 pebbles manufactured by using powder injection molding (PIM) process
  Young Ah Park, Yi-Hyun Park, Mu-Young Ahn, Young Soo Yoon
  Journal of Nuclear Materials.2024; 597: 155140.     CrossRef
• Combined simulation of micro and nanoparticles in RF inductively coupled plasma torches with the variations of metallic species and feeding nozzle location
  Cheongbin Cheon, Ho Jun Kim, Hae June Lee
  Japanese Journal of Applied Physics.2023; 62(SA): SA1014.     CrossRef
• High-throughput injection molding of transparent fused silica glass
  Markus Mader, Oliver Schlatter, Barbara Heck, Andreas Warmbold, Alex Dorn, Hans Zappe, Patrick Risch, Dorothea Helmer, Frederik Kotz, Bastian E. Rapp
  Science.2021; 372(6538): 182.     CrossRef
• Controlling the sintering response in the development of multilayered components produced via powder injection molding route—a review
  O. J. Ojo-kupoluyi, S. M. Tahir, T. T. Dele-Afolabi, M. S. Anuar
  The International Journal of Advanced Manufacturing Technology.2020; 107(9-10): 3755.     CrossRef
• Fabrication of pressureless sintered Si3N4 ceramic balls by powder injection molding
  Chang Woo Gal, Gi Woung Song, Woon Hyung Baek, Hyung Kyu Kim, Dae Keun Lee, Ki Wook Lim, Seong Jin Park
  Ceramics International.2019; 45(5): 6418.     CrossRef
• Thermal decomposition behavior and modeling of PMN-PZT ceramic feedstock with varying binder compositions
  Jae Man Park, Jun Sae Han, Chang Woo Gal, Joo Won Oh, Dongguo Lin, Jaebum Noh, Kunal H Kate, Sundar V Atre, Youngmoo Kim, Seong Jin Park
  Materials Research Express.2019; 6(6): 065316.     CrossRef
• Powder Injection Molding Process in Industrial Fields
  Joo Won OH, Chang Woo GAL, Daseul SHIN, Jae Man PARK, Woo Seok YANG, Seong Jin PARK
  Journal of the Japan Society of Powder and Powder Metallurgy.2018; 65(9): 539.     CrossRef
• Optimization of Process Condition for Fe Nano Powder Injection Molding
  Joo Won Oh, Won Sik Lee, Seong Jin Park
  Journal of Korean Powder Metallurgy Institute.2017; 24(3): 223.     CrossRef

10 wt.% and 20 wt.%Li-TiO₂ composite powders are synthesized by a sol-gel method using titanium isopropoxide and Li₂CO₃ as precursors. The as-received amorphous 10 wt.%Li-TiO₂ composite powders crystallize into the anatase-type crystal structure upon calcination at 450°C, which then changes to the rutile phase at 750°C. The asreceived 20 wt%Li-TiO₂ composite powders, on the other hand, crystallize into the anatase-type structure. As the calcination temperature increases, the anatase TiO₂ phase gets transformed to the LiTiO₂ phase. The peaks for the samples obtained after calcination at 900°C mainly exhibit the LiTiO₂ and Li₂TiO₃ phases. For a comparison of the photocatalytic activity, 10 wt.% and 20 wt.% Li-TiO₂ composite powders calcined at 450°C, 600°C, and 750°C are used. The 20 wt.%Li-TiO₂ composite powders calcined at 600°C show excellent efficiency for the removal of methylorange.

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• Refractory Metal Oxide–Doped Titanate Nanotubes: Synthesis and Photocatalytic Activity under UV/Visible Light Range
  Min-Sang Kim, Hyun-Joo Choi, Tohru Sekino, Young-Do Kim, Se-Hoon Kim
  Catalysts.2021; 11(8): 987.     CrossRef
• Photocatalytic activity of rutile TiO2 powders coupled with anatase TiO2 nanoparticles using surfactant
  Jong Min Byun, Chun Woong Park, Young In Kim, Young Do Kim
  journal of Korean Powder Metallurgy Institute.2018; 25(3): 257.     CrossRef
• Synthesis and characterization of nitrogen-doped TiO 2 coatings on reduced graphene oxide for enhancing the visible light photocatalytic activity
  Yifan Zhang, Hye Mee Yang, Soo-Jin Park
  Current Applied Physics.2018; 18(2): 163.     CrossRef

BaTiO₃-coated Fe nanofibers are synthesized via a three-step process. α-Fe₂O₃ nanofibers with an average diameter of approximately 200 nm are first prepared using an electrospinning process followed by a calcination step. The BaTiO₃ coating layer on the nanofiber is formed by a sol-gel process, and a thermal reduction process is then applied to the core-shell nanofiber to selectively reduce the α-Fe₂O₃ to Fe. The thickness of the BaTiO₃ shell is controlled by varying the reaction time. To evaluate the electromagnetic (EM) wave-absorbing abilities of the BaTiO₃@Fe nanofiber, epoxy-based composites containing the nanofibers are fabricated. The composites show excellent EM wave absorption properties where the power loss increases to the high frequency region without any degradation. Our results demonstrate that the BaTiO₃@Fe nanofibers obtained in this work are attractive candidates for electromagnetic wave absorption applications.

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• Research on Electromagnetic Wave Absorption Based on Electrospinning Technology†
  Baoding Li, Jing Qiao, Yue Liu, Haoyuan Tian, Wei Liu, Qilei Wu, Zhou Wang, Jiurong Liu, Zhihui Zeng
  Chinese Journal of Chemistry.2024; 42(7): 777.     CrossRef
• Design, synthesis, and characterization of a porous ceramic-supported CeO2 nanocatalyst for CO -free H2 evolution
  Jimin Lee, Minseob Lim, Tae Sung Kim, Kee-Ryung Park, Jong-Sik Lee, Hong-Baek Cho, Joo Hyun Park, Yong-Ho Choa
  Applied Surface Science.2021; 548: 149198.     CrossRef
• Electromagnetic wave absorption properties of Fe/MgO composites synthesized by a simple ultrasonic spray pyrolysis method
  Hyo-Ryoung Lim, Seung-Jae Jung, Tae-Yeon Hwang, Jimin Lee, Ki Hyeon Kim, Hong-baek Cho, Yong-Ho Choa
  Applied Surface Science.2019; 473: 1009.     CrossRef
• Study on the Optimization of Reduction Conditions for Samarium-Cobalt Nanofiber Preparation
  Jimin Lee, Jongryoul Kim, Yong-Ho Choa
  Journal of Korean Powder Metallurgy Institute.2019; 26(4): 334.     CrossRef

Waste SiC powders obtained from silicon wafer sludge have very low density and a narrow particle size distribution of 10-20 μm. A scarce yield of C and Si is expected when SiC powders are incorporated into the Fe melt without briquetting. Here, the briquetting variables of the SiC powders are studied as a function of the sintering temperature, pressure, and type and contents of the binders to improve the yield. It is experimentally confirmed that Si and C from the sintered briquette can be incorporated effectively into the Fe melt when the waste SiC powders milled for 30 min with 20 wt.% Fe binder are sintered at 1100°C upon compaction using a pressure of 250 MPa. XRF-WDS analysis shows that an yield of about 90% is obtained when the SiC briquette is kept in the Fe melt at 1650°C for more than 1 h.

The present study demonstrates the effect of freezing conditions on the pore structure of porous Cu-10 wt.% Sn prepared by freeze drying of CuO-SnO₂/camphene slurry. Mixtures of CuO and SnO₂ powders are prepared by ball milling for 10 h. Camphene slurries with 10 vol.% of CuO-SnO₂ are unidirectionally frozen in a mold maintained at a temperature of -30°C for 1 and 24 h, respectively. Pores are generated by the sublimation of camphene at room temperature. After hydrogen reduction and sintering at 650°C for 2 h, the green body of the CuO-SnO₂ is completely converted into porous Cu-Sn alloy. Microstructural observation reveals that the sintered samples have large pores which are aligned parallel to the camphene growth direction. The size of the large pores increases from 150 to 300 μm with an increase in the holding time. Also, the internal walls of the large pores contain relatively small pores whose size increases with the holding time. The change in pore structure is explained by the growth behavior of the camphene crystals and rearrangement of the solid particles during the freezing process.

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• Fabrication of Porous Ni by Freeze Drying and Hydrogen Reduction of NiO/Camphene Slurry
  Jae-Hun Jeong, Sung-Tag Oh, Chang-Yong Hyun
  Journal of Korean Powder Metallurgy Institute.2019; 26(1): 6.     CrossRef
• Fabrication of Al2O3 Dispersed Porous Cu by Freeze Drying of CuO-Al2O3/Camphene Slurry
  Hyunji Kang, Doh-Hyung Riu, Sung-Tag Oh
  journal of Korean Powder Metallurgy Institute.2018; 25(1): 25.     CrossRef
• Porous W-Ni Alloys Synthesized from Camphene/WO3-NiO Slurry by Freeze Drying and Heat Treatment in Hydrogen Atmosphere
  Sung Hyun Park, Seong-Min Park, So-Jeong Park, Bo-Yeong Park, Sung-Tag Oh
  Korean Journal of Materials Research.2018; 28(2): 108.     CrossRef

This study focuses on fabricating silver flake powder by a mechanical milling process and investigating the formation of flake-shaped particles during milling. The silver flake powder is fabricated by varying the mechanical milling parameters such as the amount of powder, ball size, impeller rotation speed, and milling time of the attrition ballmill. The particle size of the silver flake powder decreases with increasing amount of powder; however, it increases with increasing impeller rotation speed. The change in the particle size of the silver flake powder is analyzed based on elastic collision between the balls, taking energy loss of the balls due to the powder into consideration. The change in the particle size of the silver flake powder with mechanical milling parameters is consistent with the change in the diameter of the elastic deformation contact area of the ball, due to the collision between the balls, with milling parameters. The flake-shaped silver particles are formed at the elastic deformation contact area of the ball due to the collision.

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• Fabrication of WC/Co composite powder from oxide of WC/Co hardmetal scrap by carbothermal reduction process
  Gil-Geun Lee, Young Soo Lim
  journal of Korean Powder Metallurgy Institute.2018; 25(3): 240.     CrossRef

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• Effect of high-energy ball milling on the microstructure and mechanical properties of Ni-based ODS alloys fabricated using gas-atomized powder
  Chun Woong Park, Won June Choi, Jongmin Byun, Young Do Kim
  Journal of Materials Science.2022; 57(38): 18195.     CrossRef