In this research, it was carried out to investigate the effect of Zn substitution on magnetic properties and crystal structures of Ca-La-Co-Zn system ferrite sintered magnets. The results show that M type single phase was obtained from 0–0.2 of Zn substitution in (Ca_0.5La_0.5)_1.1Co_0.4-xZn_xFe_11.6O₁₉ sintered magnets. Magnetization of sintered magnets with same densities increase with an increase the value of Zn substitutions. Coercivity of sintered magnets with same average particle size decrease with an increase the value of Zn substitutions.

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Diamond-particle-dispersed-copper (Cu) matrix composites were fabricated by spark plasma sintering (SPS) process from the mixture of diamond particles, pure-Cu and chromium (Cr) powders. The microstructures and the thermal conductivities of the composites fabricated were examined. These composites were all well consolidated at a temperature of 1173 K for 600 s by SPS process. No reaction at the interface between the diamond particle and the Cu matrix was observed by scanning electron microscopy and X-ray diffraction analysis for the composites fabricated under the sintering conditions employed in the present study. The relative packing density of the diamond particle dispersed Cu matrix composites with Cr addition was 4.4~5.9 % higher than that without Cr addition. The thermal conductivity of the Cu/diamond composite drastically increased with Cr addition. The thermal conductivity of (Cu-Cr)-50 vol% diamond composites was 518~584 W/mK in a volume fraction range of Cr between 2.5 and 8.6 vol% in Cu matrix. Numerous transgranular fractures of diamond particles were observed on the bending fracture surface of diamond particle dispersed Cu matrix composites with Cr addition, indicating strong bonding between the diamond particle and the Cu matrix in the composite.

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In order to develop low-cost and high-strength titanium alloy, a production method using pre-alloyed titanium powder has been investigated. Ti-6Al-4V pre-alloyed powder was prepared by HDH process using Ti-6Al-4V alloy turning chip as a starting material. Mixed powder of Ti-6Al-4V pre-alloyed powder and 3 to 4 % iron powder was consolidated by hot extrusion process. In this study, the following results were obtained. Almost full densification of pre-alloyed powder has been confirmed by hot extrusion process. Titanium alloy containing high amount of iron up to 4 % can be produced without iron segregation by powder metallurgical process. This titanium alloy possibly shows higher tensile strength by 2 to 30 % than Ti-6Al-4V alloy maintaining elongation of 10 %. These data suggest that highly iron containing titanium alloy produced by pre-alloyed powder method possesses high potential as a material for aerospace and automobile.

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The composite journal bearings which have outer layer with high strength and inner layer with high wear resistance can be used as bearing materials in the industrial high-power machine. The complex layer bearing prepared by unification forming of two different mixed powders with Fe-Cu-C in outer layer and Fe-Cu-C-Ni-Mo in inner layer, and then it was sintered for various heating times at 1378 K~1403 K. Mechanical properties of the bearing were investigated by determinations of Vickers hardness and radial crushing strength. The radial crushing strength of sintered bearing with outer layer composition of Fe-Cu-C mixed powder is increased by the addition of phosphorus of 0.2~0.6 weight% (Specimen F). Nevertheless the apparent density of this complex bearing is low. The friction and wear properties in this bearing also were estimated. The sliding property to hardening steel shaft of the complex layer bearing was invested by swing-type sliding machine. Wear loss volume of Specimen F is low under high applied load it is very suitable for use of the industrial high-power machine.

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