Journal of Powder Materials (한국분말재료학회지)

The Korean Powder Metallurgy & Materials Institute (한국분말재료학회 (*구 분말야금학회))
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Pressureless Sintering and Microstructure of Pure Tungsten Powders Prepared by Ultrasonic Spray Pyrolysis

초음파 분무 열분해법으로 제조한 텅스텐 분말의 상압소결과 미세조직

  • Heo, Youn Ji (Department of Materials Science and Engineering, Seoul National University of Science and Technology) ;
  • Lee, Eui Seon (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) ;
  • Byun, Jongmin (Department of Materials Science and Engineering, Seoul National University of Science and Technology)
  • 허연지 (서울과학기술대학교 신소재공학과) ;
  • 이의선 (서울과학기술대학교 신소재공학과) ;
  • 오승탁 (서울과학기술대학교 신소재공학과) ;
  • 변종민 (서울과학기술대학교 신소재공학과)
  • Received : 2022.06.15
  • Accepted : 2022.06.24
  • Published : 2022.06.28
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Abstract

This study demonstrates the effect of the compaction pressure on the microstructure and properties of pressureless-sintered W bodies. W powders are synthesized by ultrasonic spray pyrolysis and hydrogen reduction using ammonium metatungstate hydrate as a precursor. Microstructural investigation reveals that a spherical powder in the form of agglomerated nanosized W particles is successfully synthesized. The W powder synthesized by ultrasonic spray pyrolysis exhibits a relative density of approximately 94% regardless of the compaction pressure, whereas the commercial powder exhibits a relative density of 64% under the same sintering conditions. This change in the relative density of the sintered compact can be explained by the difference in the sizes of the raw powder and the densities of the compacted green body. The grain size increases as the compaction pressure increases, and the sintered compact uniaxially pressed to 50 MPa and then isostatically pressed to 300 MPa exhibits a size of 0.71 m. The Vickers hardness of the sintered W exhibits a high value of 4.7 GPa, mainly due to grain refinement.

Keywords

Acknowledgement

이 논문은 2022년도 정부(과학기술정보통신부)의 재원으로 한국연구재단의 지원을 받아 수행된 연구임(NRF-2021R1F1A1061792).

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