The injection molded Fe sintered bodies were fabricated using two kinds of nano Fe powders, Fe-5%vol.ZrO2 and Fe-10vol.%ZrO2 powders. The relationship between microstructure and mechanical properties depending on the ZrO2 contents and sintering temperature were characterized by SEM and TEM techniques. In the wear test, the Fe-0vol%ZrO2 sintered bodies showed mainly adhesive wear, but in the Fe-5%vol. ZrO2 and Fe-10vol. % ZrO2 composites the main wear behavior showed abrasive wear mode.
The effects of compaction pressure and sintering temperature on the densification of Fe-40wt%Ni alloy nanoparticles were analyzed. The Fe-Ni nanoparticles were fabricated by an arc-discharge method and then, compacted at three different pressures and sintered at 550 to . Densification was completed at temperature as low as and high-pressure compaction was found to enhance densification. Densification behaviors and microstructure developments have been investigated through density measurements, electron microscopies, and hardness measurements.
The nano-sized Fe powders were prepared by plasma arc discharge process using pure Fe rod. The microstructure and the sintering behavior of the prepared nanopowders were evaluated. The prepared Fe nanopowders had nearly spherical shapes and consisted of metallic core and oxide shell structures. The higher volume shrinkage at low sintering temperature was observed due to the reduction of surface oxide. The nanopowders showed 6 times higher densification rate and more significant isotropic shrinkage behavior than those of micron sized Fe powders.
In recent years, micro powder injection molding is being explored as an economical fabrication method for microcomponents in microsystems technology (MST). Technical and economic comparison was performed for processes. Molding experiment and simulation during the filling process were performed to evaluate several different geometries and processing conditions. The influence of material parameters and process conditions on mold filling were examined as a function of features size using microchannels as an example. It was found that the heat conductivity and viscosity of feedstock, geometry and mold temperature were the most critical parameters for complete filling of micro features.
Small powder size is very useful in achieving detailed structures. STS 316 nanopowders with an average diameter of 100 nm and were utilized to produce feedstock. The mixing behavior of the feedstock indicated that the nanoparticle feedstock produced the highest mixing torque at various powder loading compared to the micropowder feedstock. The nanoparticles feedstocks showed that elastic properties are dominant in flow behavior and high viscosity. Conversely the micropowders feedstocks, viscous properties are dominant in flow behavior and less viscosity, nanopowders feedstock perform lower flow activation energy than feedstock with bigger particles.