Journal of Powder Materials (한국분말재료학회지)

The Korean Powder Metallurgy & Materials Institute (한국분말재료학회 (*구 분말야금학회))
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A Feasibility Study on the Surface Hardening of Sintered Iron Nanopowder by Plasma Ion Nitriding

플라즈마 이온질화에 의한 Fe 나노분말소결체의 표면경화 가능성 연구

  • Yun, Joon-Chul (Department of Metallurgy and Materials Science, Hanyang University) ;
  • Lee, Jai-Sung (Department of Metallurgy and Materials Science, Hanyang University)
  • 윤준철 (한양대학교 금속재료공학과) ;
  • 이재성 (한양대학교 금속재료공학과)
  • Received : 2011.11.29
  • Accepted : 2012.01.20
  • Published : 2012.02.28
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Abstract

This study has been performed on the full density sintering of Fe nanopowder and the surface hardening by plasma ion nitriding. The Fe sintered part was fabricated by pressureless sintering of the Fe nanopowder at $700^{\circ}C$ in which the nanopowder agglomerates were controlled to have 0.5-5 ${\mu}m$ sized agglomerates with 150 nm Fe nanopowders. The green compact with 46% theoretical density(T.D.) showed a homogeneous microstructure with fine pores below 1 ${\mu}m$. After sintering, the powder compact underwent full densification process with above 98%T.D. and uniform nanoscale microstructure. This enhanced sintering is thought to be basically due to the homogeneous microstructure in the green compact in which the large pores are removed by wet-milling. Plasma ion nitriding of the sintered part resulted in the formation of ${\gamma}$'-$Fe_4N$ equilibrium phase with about 12 ${\mu}m$ thickness, leading to the surface hardening of the sintered Fe part. The surface hardness was remarkably increased from 176 $H_v$ for the matrix to 365 $H_v$.

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References

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