Journal of Powder Materials (한국분말재료학회지)

The Korean Powder Metallurgy & Materials Institute (한국분말재료학회 (*구 분말야금학회))
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Effect of Powder Characteristic and Freeze Condition on the Pore Characteristics of Porous W

텅스텐 다공체의 기공특성에 미치는 분말특성 및 동결조건의 영향

  • Kwon, Na-Yeon (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Oh, Sung-Tag (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
  • 권나연 (서울과학기술대학교 신소재공학과) ;
  • 오승탁 (서울과학기술대학교 신소재공학과)
  • Received : 2012.06.08
  • Accepted : 2012.07.16
  • Published : 2012.08.28
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Abstract

Dependence of the freeze-drying process condition on microstructure of porous W and pore formation mechanism were studied. Camphene slurries with $WO_3$ contents of 10 vol% were prepared by milling at $50^{\circ}C$ with a small amount of dispersant. Freezing of a slurry was done in Teflon cylinder attached to a copper bottom plate cooled at $-25^{\circ}C$. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was hydrogen-reduced at $800^{\circ}C$ for 30 min, and sintered in the furnace at $900^{\circ}C$ for 1 h. After heat treatment in hydrogen atmosphere, $WO_3$ powders were completely converted to metallic W without any reaction phases. The sintered samples showed large pores with the size of about $70{\mu}m$ which were aligned parallel to the camphene growth direction. Also, the internal wall of large pores and near bottom part of specimen had relatively small pores with dendritic structure due to the growth of camphene dendrite depending on the degree of nucleation and powder rearrangement in the slurry.

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References

  1. J. Banhart: Prog. Mater. Sci., 46 (2001) 559. https://doi.org/10.1016/S0079-6425(00)00002-5
  2. H. Nakajima: Prog. Mater. Sci., 52 (2007) 1091. https://doi.org/10.1016/j.pmatsci.2006.09.001
  3. P. S. Liu and K. M. Liang: J. Mater. Sci., 36 (2001) 5059. https://doi.org/10.1023/A:1012483920628
  4. T. Fukasawa, M. Ando, T. Ohji and S. Kanzaki: J. Am. Ceram. Soc., 84 (2001) 230. https://doi.org/10.1111/j.1151-2916.2001.tb00638.x
  5. Y.-H. Koh, J.-H. Song, E.-J. Lee and H.-E. Kim: J. Am. Ceram. Soc., 89 (2006) 3089. https://doi.org/10.1111/j.1551-2916.2006.01222.x
  6. T. Fukasawa, Z.-Y. Deng, M. Ando, T. Ohji and S. Kanzaki: J. Am. Ceram. Soc., 85 (2002) 2151. https://doi.org/10.1111/j.1151-2916.2002.tb00426.x
  7. K. K. Mallick: J. Am. Ceram. Soc., 92 (2009) S85. https://doi.org/10.1111/j.1551-2916.2008.02784.x
  8. M.-S. Kim, S.-T. Oh, S.-Y. Chang and M.-J. Suk: J. Kor. Powd. Met. Inst., 18 (2011) 327 (Korean). https://doi.org/10.4150/KPMI.2011.18.4.327
  9. S.-W. Yook, B.-H. Yoon, H.-E. Kim, Y.-H. Koh and Y.-S. Kim: Mater. Lett., 62 (2008) 4506. https://doi.org/10.1016/j.matlet.2008.08.010
  10. Y.-S. Lee and S.-T. Oh: Kor. J. Mater. Sci., 21 (2011) 520 (Korean). https://doi.org/10.3740/MRSK.2011.21.9.520
  11. K. Araki and J.W. Halloran: J. Am. Ceram. Soc., 87 (2004) 1859.
  12. H. J. Hwang and J.-W. Moon: J. Korean Ceram. Soc., 41 (2004) 229 (Korean). https://doi.org/10.4191/KCERS.2004.41.3.229
  13. B.-H. Yoon, E.-J. Lee, H.-E. Kim and Y.-H. Koh: J. Am. Ceram. Soc., 90 (2007) 1753. https://doi.org/10.1111/j.1551-2916.2007.01703.x
  14. N.O. Shanti, K. Araki and J. W. Halloran: J. Am. Ceram. Soc., 89 (2006) 2444. https://doi.org/10.1111/j.1551-2916.2006.01094.x
  15. S. Deville, E. Maire, G. Bernard-Granger, A. Lasalle, A. Bogner, C. Gauthier, J. Leloup and C. Guizard: Nature Mater., 8 (2009) 966. https://doi.org/10.1038/nmat2571

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