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Name (Title):
Byung Joo Park ( ICYS-SENGEN researcher)
Affiliation:
International Center for Young Scientists-SENGEN, NIMS
Address:
National Institute for Materials Science
1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 JAPAN
Email: Park.Byungjoo@nims.go.jp
Home Page:
Presentation Title:
Nano structured materials design with phase separation
Abstract:
The phase separation has been extensively studied both experimentally and theoretically.[1]
The phase separation is observed in mixtures of various types of condensed matter such as
liquids, metals, polymers, and glasses. Due to the presence of immiscibility, the phase separating
systems present a unique opportunity for designing composites with hierarchical microstructure
at different length scales and provide opportunity for developing materials with unique
properties. For example, phase separating silicate glasses are well known and are widely studied
for scientific understanding and technological exploitation such as Vycor and Pyrex glasses.
Additionally, to understand the phase separation mechanism can give an opportunity to design
the nano porous materials. Porous metallic materials have been used in lots of fields including
aerospace, electrochemistry, petrochemistry, medicine and substitute energy related research.
Their distinctive structures make them very useful as lightweight structural materials, separation
membranes, catalyst supports, impact energy absorbers, acoustic dampeners, and heat
exchangers.[2] But there are still many challenges to improve the properties of porous materials
with controlling the porous size and shape.
In present study, we designed the phase separating FeCu and CoCu binary system with
thermodynamic calculation. From the calculated critical composition, the interconnected phases
are observed in melt spun ribbon sample. The
perfectly interconnected metallic porous
materials could be synthesized from the
separated two different phases by the selective
dissolution method. Because the difference of
chemical activity of separated phases, Fe rich,
Co rich, and Cu rich phases were selectively
dissolved in the nitric acid. Finally, the iron
based in Fig. 1. the cobalt based and Cu based
metallic porous materials have been formed. The
synthesized porous ribbon could be used as a
membrane supporter that can reduce the
thickness of Pd layer for hydrogen separation.
References:
[1] B. J. Park et al., Phys. Rev. Lett., 96, 245503 (2006)
[2] J. Banhart, Prog. Mater. Sci. 46, 559 (2001)
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Oral Presentation 28
Fig. 1 Scanning electron microscope images. . The
chemical dissolved (a) surface and (b) cross section
of the iron based porous ribbon sample.