In this study, effect of core-shell structure on compaction behavior of harmonic powder is investigated. Harmonic powders are made by electroless plating method on Fe powders. Softer Cu shell encloses harder Fe core, and the average size of Fe core and thickness of Cu shell are 34.3 μm and 3.2 μm, respectively. The powder compaction procedure is processed with pressure of 600 MPa in a cylindrical die. Due to the low strength of Cu shell regions, the harmonic powders show better densification behavior compared with pure Fe powders. Finite element method (FEM) is performed to understand the roll of core-shell structure. Based on stress and strain distributions of FEM results, it is concluded that the early stage of powder compaction of harmonic powders mainly occurs at the shell region. FEM results also well predict porosity of compacted materials.

In this study, in order to increase surface ability of hardness and corrosion of magnesium alloy, anodizing and sealing with nano-diamond powder was conducted. A porous oxide layer on the magnesium alloy was successfully made at 85°C through anodizing. It was found to be significantly more difficult to make a porous oxide layer in the magnesium alloy compared to an aluminum alloy. The oxide layer made below 73°C by anodizing had no porous layer. The electrolyte used in this study is DOW 17 solution. The surface morphology of the magnesium oxide layer was investigated by a scanning electron microscope. The pores made by anodizing were sealed by water and aqueous nanodiamond powder respectively. The hardness and corrosion resistance of the magnesium alloy was increased by the anodizing and sealing treatment with nano-diamond powder.

Citations

Citations to this article as recorded by  

• The effect of different turbulent flow on failure behavior in secondary loop of the pressurized water reactor
  Y. Hu, L. Zhao, Y.H. Lu, T. Shoji
  Nuclear Engineering and Design.2020; 368: 110812.     CrossRef
• Effect of heat treatment on corrosion resistance and adhesion property in Zn-Mg-Zn multi-layer coated steel prepared by PVD process
  Jong Min Byun, Su-Ryong Bang, Hyun Woo Kim, Tae-Yeob Kim, Suk-Jun Hong, Young Do Kim
  Surface and Coatings Technology.2017; 309: 1010.     CrossRef
• Convergent Study of Aluminum Anodizing Method on the Thermal Fatigue
  Soo Young Kang
  Journal of the Korea Convergence Society.2016; 7(5): 169.     CrossRef
• Convergent Study of Texture on the Mechanical Properties of Electrodeposits
  Soo Young Kang
  Journal of the Korea Convergence Society.2016; 7(6): 193.     CrossRef

In this study, an aluminum oxide layer for sealing treatment of nano-diamond powder was synthesized by anodizing under constant current. The produced pore size and oxide thickness were investigated using scanning electron microscopy. The pore size increased as the treatment time increased, current density increased, sulfuric acid concentration decreased, which is different from the results under constant voltage, due to a dissolution of the oxide layers. The oxide layer thickness by the anodizing increased as temperature, time, and current density increased. The results of this study can be applied to optimize the sealing treatment process of nano-diamond particles of 4-10 nm to enhance the resistances of corrosion and wear of the matrix.

Citations

Citations to this article as recorded by  

• Convergent Study of Aluminum Anodizing Method on the Thermal Fatigue
  Soo Young Kang
  Journal of the Korea Convergence Society.2016; 7(5): 169.     CrossRef
• Convergent Study of Texture on the Mechanical Properties of Electrodeposits
  Soo Young Kang
  Journal of the Korea Convergence Society.2016; 7(6): 193.     CrossRef
• Study on Improvement of Corrosion Resistance and Wear Resistance by Anodizing and Sealing Treatment with Nano-diamond Powder on aluminum
  Soo Young Kang, Dae Won Lee
  Journal of the Korean institute of surface engineering.2014; 47(3): 121.     CrossRef
• Study on Hardness and Corrosion Resistance of Magnesium by Anodizing and Sealing Treatment With Nano-diamond Powder
  Soo Young Kang, Dae Won Lee
  Journal of Korean Powder Metallurgy Institute.2014; 21(4): 260.     CrossRef