Journal of Powder Materials

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[Korean]
Fabrication of Porous Cu-Ni by Freeze Drying and Hydrogen Reduction of CuO-NiO Powder Mixture: Han Gil Seo, Sung-Tag Oh; J Korean Powder Metall Inst. 2014;21(1):34-38. Published online February 1, 2014; DOI: https://doi.org/10.4150/KPMI.2014.21.1.34

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Cu-Ni alloys with unidirectionally aligned pores were prepared by freeze-drying process of CuO-NiO/camphene slurry. Camphene slurries with dispersion stability by the addition of oligomeric polyester were frozen at -25°C, and pores in the frozen specimens were generated by sublimation of the camphene during drying in air. The green bodies were hydrogen-reduced at 300°C and sintered at 850°C for 1 h. X-ray diffraction analysis revealed that CuO-NiO composite powders were completely converted to Cu-Ni alloy without any reaction phases by hydrogen reduction. The sintered samples showed large and aligned parallel pores to the camphene growth direction, and small pores in the internal wall of large pores. The pore size and porosity decreased with increase in CuO-NiO content from 5 to 10 vol%. The change of pore characteristics was explained by the degree of powder rearrangement in slurry and the accumulation behavior of powders in the interdendritic spaces of solidified camphene.

Citations

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Enhancement in electrical conductivity of pastes containing submicron Ag-coated Cu filler with palmitic acid surface modification
Eun Byeol Choi, Jong-Hyun Lee
Applied Surface Science.2017; 415: 67. CrossRef
Investigation for Microstructure and Hardness of Welded Zone of Cu-Ni Alloy using W92-Ni-Fe Sintering Tool
Tae-Jin Yoon, Sang-Won Park, Myung-Chang Kang, Joong-Suk Noh, Sung-Wook Chung, Chung-Yun Kang
Journal of Korean Powder Metallurgy Institute.2015; 22(3): 181. CrossRef
Controlling Structural and Electrical Properties of Pt Nanopowder-Dispersed SiO2Film
Jae Ho Lee, In Joo Shin, Sung Woo Lee, Hyeong Cheol Kim, Byung Joon Choi
Journal of Korean Powder Metallurgy Institute.2014; 21(5): 355. CrossRef

[Korean]
Freeze Drying for Porous Mo with Sublimable Vehicles of Eutectic System: Gyu-Tae Lee, Han Gil Seo, Myung-Jin Suk, Sung-Tag Oh; J Korean Powder Metall Inst. 2013;20(4):253-257.; DOI: https://doi.org/10.4150/KPMI.2013.20.4.253

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Freeze drying for porous Mo was accomplished by using MoO_3 powder as the source and camphor-naphthalene eutectic system as the sublimable material. Eutectic composition of camphor-naphthalene slurries with the initial MoO_3 content of 5 vol%, prepared by milling at 55°C with a small amount of oligomeric dispersant, was frozen at -25°C. The addition of dispersant showed improvement of dispersion stability in slurries. Pores were generated subsequently by sublimation of the camphor-naphthalene during drying in air for 48 h. To convert the MoO_3 to metallic Mo, the green body was hydrogen-reduced at 750°C, and sintered at 1100°C for 2 h. The sintered samples, frozen by heated Teflon cylinder, showed large pores with the size of about 40 µm which were aligned parallel to the sublimable vehicles growth direction. The formation of unidirectionally aligned pores is explained by the rejection and accumulation of solid particles in the serrated solid-liquid interface.

Citations

Citations to this article as recorded by

Interaction of Solid Particles with the Solidifying Front in the Liquid-Particle Mixture
Ho-Suk Lee, Kyu-Hee Lee, Sung-Tag Oh, Young Do Kim, Myung-Jin Suk
Journal of Korean Powder Metallurgy Institute.2018; 25(4): 336. CrossRef
Freeze drying for porous Mo with different sublimable vehicle compositions in the camphor-naphthalene system
Sung-Tag Oh, Young Do Kim, Myung-Jin Suk
Materials Letters.2015; 139: 268. CrossRef

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