Ni-based oxide dispersion strengthened (ODS) alloys have a higher usable temperature and better hightemperature mechanical properties than conventional superalloys. They are therefore being explored for applications in various fields such as those of aerospace and gas turbines. In general, ODS alloys are manufactured from alloy powders by mechanical alloying of element powders. However, our research team produces alloy powders in which the Ni5Y intermetallic phase is formed by an atomizing process. In this study, mechanical alloying was performed using a planetary mill to analyze the milling behavior of Ni-based oxide dispersions strengthened alloy powder in which the Ni5Y is the intermetallic phase. As the milling time increased, the Ni5Y intermetallic phase was refined. These results are confirmed by SEM and EPMA analysis on microstructure. In addition, it is confirmed that as the milling increased, the mechanical properties of Ni-based ODS alloy powder improve due to grain refinement by plastic deformation.

The microstructural and mechanical properties of Al-Si alloyed powder, prepared by gas atomization fallowed by hot extrusion, were studied by optical and scanning electron microscopies, hardness and wear testing. The gas atomized Al-Si alloy powder exhibited uniformly dispersed Si particles with particle size ranging from 5 to . The hot extruded Al-Si alloy shows the average Si particle size of less than . After heat-treatment, the average particle size was increased from 2 to . Also, mechanical properties of extruded Al-Si alloy powder were analyzed before and after heat-treatment. As expected from the microstructural analysis, the heat-treated samples resulted in a decrease in the hardness and wear resistance due to Si particle growth. The friction coefficient of heat-treated Al-Si alloyed powder showed higher value tough all sliding speed. This behavior would be due to abrasive wear mechanism. As sliding speed increases, friction coefficient and depth and width of wear track increase. No significant changes occurred in the wear track shape with increased sliding speed.

This paper described the preparation method for composing high-grade synthetic diamond by water atomizing using FeNi30 powder catalyst. The objective of this article is about powder making process using super high water atomizing in the atmosphere of inert gas, and then corroded the powder with a corrosion inhibitor. Finally, FeNi30 catalyst powder with lower oxygen content and good sphericity is produced. The experiment of making diamonds by using cubic press and the performance of the diamonds are also discussed.

Flying trajectories of fine particles within a size range of were studied during centrifugal atomizing processes. A FORTRAN program was written by using increment method. Calculation results revealed that the drag force might reach very high value of 522-7800 g for fine powder of . Flying distance in horizontal direction could be shortened if the particles fly obliquely due to the huge drug force. On the other hand, very fine powder could be projected to far distances when the atmosphere flow velocity is much stronger. Fortunately such particles could be contracted within a cylinder closed to the atomizer when the atmosphere flow was weaken or retained in a limited diameter.

To improve the properties of fine metal powder, such as particle size distribution and geometric standard deviation, this work was done at various atomizing conditions. The new atomization mechanism and the correlation equation were proposed to estimate the mean particle diameter.

This study was conducted to investigate the possibility of utilizing various types of nozzles and gas-liquid mixers to increase the dissolution rate of plasma gas containing ozone generated in a dielectric barrier plasma reactor. After selecting the air atomizing nozzle with the highest gas dissolution rate among the 13 types of test equipment, we investigated the influence of the operating factors on the air atomizing nozzle to determine the optimal plasma gas dissolution method. The gas dissolution rate was measured by a simple and indirect method, specifically, the measurement of KLa instead of direct measurement of ozone concentration, which requires a longer analysis time. The results showed that the KLa value of the simple mix of air and water was 0.372 min-1, Which is 1.44 times higher than that (0.258 min-1) of gas emitted from a normal diffuser. Among the nozzles of the same type, the KLa value was highest for the nozzle having the smallest orifice diameter. Among the 13 types of devices tested, the nozzle with highest KLa value was the M22M nozzle, which is a gas-liquid spray nozzle. The relationship between water circulation flow rate and KLa value in the experimental range was linear. The air supply flow rate and KLa value showed a parabolic-type correlation, while the optimum air supply flow rate for the water circulation flow rate of 1.8 L / min is 1.38 times.