EFFECT OF SURFACTANT CONCENTRATION ON ALUMINA NANOPARTICLE-NICKEL-IRON COMPOSITES

Open Access
Author:
Reinert, Owen Tanner
Area of Honors:
Chemical Engineering
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Manish Kumar, Thesis Supervisor
  • Andrew Zydney, Honors Advisor
Keywords:
  • nanoparticle
  • electrodeposition
  • EIS
  • electrochemical frequency modulation
  • electochemical impedance spectroscopy
  • EFM
  • surfactant
  • dispersion
  • iron
  • nickel
  • alumina
  • linear polarization resistance
  • scanning electron microscopy
  • energy dispersive X-ray spectroscopy
  • galvanodynamic scanning
  • passivation
  • catalysts
  • corrosion
  • alloys
  • surfactant concentration
  • EEC-1659653
  • REU
  • NSF
Abstract:
Iron and nickel alloys serve as catalysts in several industries despite their quick degradation. Previous research has shown that addition of alumina nanoparticles can affect corrosion and catalytic properties, but no research has investigated the effects of nanoparticle dispersion on these properties. The parameter of nanoparticle dispersion was varied by varying the amount of surfactant in the solution used for electrodeposition. The objective of this thesis was to evaluate various testing techniques to determine their efficacy for nano-scale surfaces while calculating corrosion parameters such as polarization resistance and corrosion current, as a function of surfactant concentration. Experiments were performed by sequentially increasing the surfactant concentration before electrodeposition, with the resulting samples subjected to various characterizations and corrosion tests. Investigative techniques included scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), galvanodynamic scanning (GDS), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM. It was found that most corrosion properties followed a checkmark or inverted checkmark pattern, with the 1 g/L and the 100 g/L samples being the extrema. The Tafel constant decreases and corrosion voltage increases in excess of 1 g/L surfactant. This indicates that when corrosion is slowest (1 g/L SDS) it also is thermodynamically the most likely to occur. The 100 g/L SDS sample was quickest but least thermodynamically likely to corrode, potentially indicating a passivation layer. XRD was found to be ineffective for very thin films. EFM proved to be better at calculating the Tafel constant because EFM directly yields the Tafel constant, while GDS requires guesswork when slopes are not precisely linear.