Browse > Article
http://dx.doi.org/10.3740/MRSK.2015.25.11.602

Fabrication of Porous W by Freeze-Drying Process of Camphene Slurries with Spherical PMMA and WO3 Powders  

Lee, Han-Eol (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Jeon, Ki Cheol (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Kim, Young Do (Division of Materials Science and Engineering, Hanyang University)
Suk, Myung-Jin (Department of Materials and Metallurgical Engineering, Kangwon National University)
Oh, Sung-Tag (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
Publication Information
Korean Journal of Materials Research / v.25, no.11, 2015 , pp. 602-606 More about this Journal
Abstract
Porous W with spherical and directionally aligned pores was fabricated by the combination of sacrificial fugitives and a freeze-drying process. Camphene slurries with powder mixtures of $WO_3$ and spherical PMMA of 20 vol% were frozen at $-25^{\circ}C$ and dried for the sublimation of the camphene. The green bodies were heat-treated at $400^{\circ}C$ for 2 h to decompose the PMMA; then, sintering was carried out at $1200^{\circ}C$ in a hydrogen atmosphere for 2 h. TGA and XRD analysis showed that the PMMA decomposed at about $400^{\circ}C$, and $WO_3$ was reduced to metallic W at $800^{\circ}C$ without any reaction phases. The sintered bodies with $WO_3$-PMMA contents of 15 and 20 vol% showed large pores with aligned direction and small pores in the internal walls of the large pores. The pore formation was discussed in terms of the solidication behavior of liquid camphene with solid particles. Spherical pores, formed by decomposition of PMMA, were observed in the sintered specimens. Also, microstructural observation revealed that struts between the small pores consisted of very fine particles with size of about 300 nm.
Keywords
porous W; pore forming agent; freeze-drying; hydrogen reduction; pore structure;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 P. S. Liu and K. M. Liang, J. Mater. Sci., 36, 5059 (2001).   DOI
2 J. Banhart, Prog. Mater. Sci., 46, 559 (2001).   DOI
3 M. -J. Suk and Y. -S. Kwon, J. Korean Powder Metall. Inst., 8, 215 (2001) (in Korean).
4 H. Nakajima, Prog. Mater. Sci., 52, 1091 (2007).   DOI
5 T. Ohji and M. Fukushima, Intern. Mater. Rev., 57, 115 (2012).   DOI
6 D. H. Yang, B. Y. Hur and S. R. Yang, J. Alloy. Compd., 461, 221 (2008).   DOI
7 Z. -Y. Deng, J. -F. Yang, Y. Beppu, M. Ando and T. Ohji, J. Am. Ceram. Soc., 85, 1961 (2002).   DOI
8 I. H. Song, I. -M. Kwon, H. D. Kim and Y. W. Kim, J. Eur. Ceram. Soc., 30, 2671 (2010).   DOI
9 T. Fukasawa, M. Ando, T. Ohji and S. Kanzaki, J. Am. Ceram. Soc., 84, 230 (2001).   DOI
10 K. C. Jeon, Y. D. Kim, M. -J. Suk and S. -T. Oh, J. Korean Powder Metall. Inst., 22, 129 (2015) (in Korean).
11 S. -T. Oh, Y. D. Kim and M.-J. Suk, Mater. Lett., 139, 268 (2015).   DOI
12 O. Mengual, G. Meunier, I. Cayre, K. Puech and P. Snabre, Talanta, 50, 445 (1999).   DOI
13 N. H. Kim, H. Song, S. C. Choi and Y. H. Choa, J. Korean Powder Metall. Inst., 16, 262 (2009) (in Korean).
14 T. R. Wilken, W. R. Morcom, C. A. Wert and J. B. Woodhouse, Metall. Trans. B, 7, 589 (1976).   DOI
15 Y. -S. Lee and S. -T. Oh, Korean J. Mater. Res., 21, 520 (2011) (in Korean).   DOI
16 S. Deville, Adv. Eng. Mater., 10, 155 (2008).   DOI
17 D. -G. Kim, S. -T. Oh, H. Jeon, C. -H. Lee and Y. D. Kim, J. Alloy. Compd., 354, 239 (2003).   DOI