Korean Journal of Materials Research (한국재료학회지)

Materials Research Society of Korea (한국재료학회)
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Porous W-Ni Alloys Synthesized from Camphene/WO3-NiO Slurry by Freeze Drying and Heat Treatment in Hydrogen Atmosphere

Camphene/WO3-NiO 슬러리의 동결건조 및 수소분위기 열처리에 의한 W-Ni 다공체 제조

  • Park, Sung Hyun (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Park, Seong-Min (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Park, So-Jeong (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Park, Bo-Yeong (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)
  • 박성현 (서울과학기술대학교 신소재공학과) ;
  • 박성민 (서울과학기술대학교 신소재공학과) ;
  • 박소정 (서울과학기술대학교 신소재공학과) ;
  • 박보영 (서울과학기술대학교 신소재공학과) ;
  • 오승탁 (서울과학기술대학교 신소재공학과)
  • Received : 2017.12.14
  • Accepted : 2017.12.26
  • Published : 2018.02.27
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Abstract

The present study demonstrates the effect of raw powder on the pore structure of porous W-Ni prepared by freeze drying of camphene-based slurries and sintering process. The reduction behavior of $WO_3$ and $WO_3-NiO$ powders is analyzed by a temperature programmed reduction method in Ar-10% H2 atmosphere. After heat treatment in hydrogen atmosphere, $WO_3-NiO$ powder mixture is completely converted to metallic W without any reaction phases. Camphene slurries with oxide powders are frozen at $-30^{\circ}C$, and pores in the frozen specimens are generated by sublimation of the camphene during drying in air. The green bodies are hydrogen-reduced at $800^{\circ}C$ and sintered at $1000^{\circ}C$ for 1 h. The sintered samples show large and aligned parallel pores to the camphene growth direction, and small pores in the internal wall of large pores. The strut between large pores, prepared from pure $WO_3$ powder, consists of very fine particles with partially necking between the particles. In contrast, the strut densification is clearly observed in the Ni-added W sample due to the enhanced mass transport in activation sintering.

Keywords

References

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