Development of nanoparticulate materials technology is essential to processing of highly functional nanoparticulate materials and components with small and complex shape. This paper provides an overview on our recent investigations on the processing of net‐shaped nanocrystalline Fe‐Ni powder and related material property such as mechanical property. The key‐processing concept is the synthesis of nanopowders and subsequent consolidation with controlled microstructure by using powder injection molding (PIM) process. Especially, the pressureless sintering process is inevitable for consolidation of the PIMed nanopowder. The present review focuses on the densification process and related mechanical property of the PIMed Fe‐Ni nanopowder in association with microstructural evolution and diffusion process.

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Densification behavior of nano-agglomerate powder during pressureless sintering of Fe-Ni nanopowder was investigated in terms of diffusion kinetics and microstructural development. To understand the role of agglomerate boundary for sintering process, densification kinetics of Fe-Ni nano-agglomerate powder with different agglomerate size was investigated. It was found that activation energy for densification process was lower in the small-sized agglomerate powder. The increase in the volume fraction of inter-agglomerate boundary acting as high diffusion path might be responsible for the enhanced diffusion process.

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This paper overviews our recent investigations on the processing of net-shaped Fe-based nanoparticulate materials and their related material properties such as mechanical and corrosion properties. The key-process for fabricating fully densified net-shaped nanopowder by pressureless sintering is an optimal control of agglomerate size of nanopowder. Enhanced mechanical property of powder injection molded Fe-Ni nanopowder could be explained by grain refinement and uniformity of microstructure.