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Synthesis and Investigation of Corrosion Resistance and Mechanical Properties of Ni-Fe Multilayer Coatings with SiC Particles

Abedi, Masoumeh | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 56773 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Ghorbani, Mohammad
  7. Abstract:
  8. Electrochemical deposition of multilayer coatings is one of the surface engineering techniques to create thin surface layers with a controlled structure in order to create desirable surface properties. In this research, the nickel-iron-silicon carbide multilayer coating is deposited from a single bath with a sulfate composition and by changing the current density between two values (10 and 40 mA/cm2). The number of layers in multilayer coating was 4, 8, 16, 32.The effect of current density and the number of layers on chemical composition, surface morphology, phase structure, corrosion resistance, nano hardness measurement, wear resistance of multilayer coatings respectively using electron spectrum diffractometer, FE-SEM microscope, X-ray analysis, Tafel polarization and impedance, nano hardness test and pin on disk test was investigated and compared with monolayer coatings in the current density of 10 and 40 mA/cm2.The corrosion current densities of monolayers in current density of 10 and 40 mA/cm2 were 1.5×10-6 and 5.7×10-6 A/cm2 respectively, and corrosion rate decreased by layering and reached to the optimal value of 1.2×10-6 A/cm2 in 16 layer coating. The polarization resistance(Rp) of monolayers in current density of 10 and 40 mA/cm2 were 1461 and 950 Ω.cm2 respectively, and the polarization resistance increased by increasing number of layers and reached to the optimal value of 1608 in 16 layer coating. The electrical circuit that was proposed to model the corrosion process shows that multilayering makes the structure of the coatings more compact and thus improve the corrosion properties of the coating. The hardness of the monolayer coatings at the current density of 10 and 40 mA/cm2 were 5.81 and 5.022 Gpa, respectively, and the hardness decreased with the increasing the number of layers and reached to the 1.17 Gpa in 16 layer coating. The amount of weight loss of the samples after the wear test at the current density of 10 and 40 mA/cm2 were 0.0009 and 0.001 g respectively, and the amount of weight loss increased with the increasing in the number of layers and reached the value of 0.0014 g in 16 layer coating
  9. Keywords:
  10. Electrochemical Deposition ; Multi-Layer Coating ; Corrosion ; Hardness ; Wear ; Nickel-Iron-Silicon Carbide Coating ; Corrosion Resistance ; Mechanical Properties

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