The efects of mechanical aloying conditions and the type of reducing agent on the solid state reductionof haematite have been investigated at room temperature. Aluminium titanium zinc and copper were used as reducing agent. Nanocomposites of metal-oxide in which oxide particles with nano size were dispersed in Fe matrix were obtained by mechanical alloying of with aluminium and titanium respectively However the reduction of by coppe was not occurred Composite materials of iron with and were obtained from the system of and after ball milling for 20 hrs and 30 hrs respectively. And the system of resulted in the formationof FeO with ZnO after ball milling of 120 hrs. The final grain sizes of iron estimated by X-ray diffraction line-width measurement were in the ranges of 24~33 nm.

In this work, the conventional transient liquid phase(TLP) bonding was modified. An attempt was made of using a liquid phase sintered alloy, which will be a liquid phase coexisting with a solid phase at the bonding temperature, as an interlayer for bonding metals. With an aim of revealing the fundamental features of this modified TLP bonding, the kinetics concerned with the growth of solid particles and the isothermal solidification process in Fe-1.16wt%B and Fe-4.5wt%P interlayers for the bonding pure iron, as well as the morphological change of the solid particle, were investigated.

The semiconducting compound has been recognized as a thermoelectric material with excel-lent oxidation resistance and stable characteristics at elevated temperature. In the present work, we applied mechanical alloying(MA) technique to produce compound using a mixture of elemental iron and silicon powders. The mechanical alloying was carried out using a Fritsch P-5 planetary mill under Ar gas atmosphere. The MA powders were characterized by the X-ray diffraction with Cu-K radiation, thermal analysis and scanning electron microscopy. The single phase has been obtained by mechanical alloying of mixture powders for 120 hrs or for 70 hrs coupled with the subsequent heat treatment up to . The grain size of powders analyzed by Hall plot method was 44nm.

Spark-Plasma Sintering(SPS) is one of the new sintering methods which takes advantages both inconventional pressure sintering and electric current sintering. It is known that SPS is very effective for the densification of hard-to-sinter materials like refractory metals, intermetallic compounds, glass and ceramics without grain growth. However, a clear explanation for sintering mechanism and an experimental evidence for the formation of weak plasma during SPS are not given yet. In this study, fundamental study on sintering behavior and mechanism of SPS was investiged. For this study, various spherical Fe powders were prepared such as as-received, as-reduced, and as-oxidized and then sintered by SPS facility. In order to confirm the surface cleaning effect during SPS neck region and fracture surface of sintered body was observed and analyzed by SEM/EPMA. Densification behavior was analyzed from the data of deflection along the pressure axis. Some specimens were additionally produced by Hot Pressing and the results were compared with those of SPS.

Mechanical alloying technique was applied to prepare hard magnetic compound powders. Staring from pure Fe and Sm powders, the formation process of hard magnetic phase by mechanical alloying and subsequent solid state reaction was studied. As milled powders were found to consist of Sm-Fe amorphous and -Fe phases in all compositions of (x = 11, 13, 15, 17). The effects of starting composition on the formation of intermetallic compound was investigated by heat treatment of mechanically-alloyed powders. When Sm content was 15 at.％, heat-treated powders consisted of nearly single phase. For preparation of hard magnetic powders, additional nitriding treatment was performed under gas flow at 45. The increase in the coercivity and remanence was proportional to the nitrogen content which increased drastically at first and then increased gradually as the nitriding time was extended to 3 hours.

Mechanically-alloyed NiAl powder and ball-milled (Ni+Al) powder mixture were sintered by spark-plasma sintering(SPS) process. Mechanical alloying was performed in a horizontal attritor for 20 h with rotation speed of 600 rpm. (Ni+Al) powder mixtures were prepared by ball milling for 1 and 10 h with 120 rpm. Both powders were sintered at for 5 min under torr vacuum with 50 MPa die pressure in a SPS facility. Sintered densities of 97% and 99% were obtained from mechanically-alloyed NiAl powder and (Ni+Al) powder mixture, respectively. The sintered compact of (Ni+Al) powder mixture showed large grain size by a very rapid grain growth, while the grain size of mechanically-alloyed NiAl powder compact after sintering was extremely fine(80 nm). The difference in densification behavior of both powders were discussed.