Now showing 1 - 5 of 5
  • Publication
    AC and DC anodization on the electrochemical properties of SS304L: A comparison
    This study investigates the application of alternating current (AC) and direct current (DC) anodization techniques on stainless steel 304L (SS304L) in an ethylene glycol and ammonium fluoride (NH4F) electrolyte solution to produce a nano-porous oxide layer. With limited research on AC anodizing of stainless steel, this study focuses on comparing AC and DC anodization in terms of current density versus time response, phase analysis using X-ray diffraction (XRD), and corrosion rate determined by linear polarization. Both AC and DC anodization were performed for 60 minutes at 50 V in an electrolyte solution containing 0.5% NH4F and 3% H2O in ethylene glycol. The results show that AC anodization exhibited higher current density compared to DC anodization. XRD analysis revealed the presence of ferrite (α-Fe) and austenite (γ-Fe) phases in the as-received specimen, while both AC and DC anodized specimens exhibited only the γ-Fe phase. The corrosion rate of the AC-anodized specimen was measured at 0.00083 mm/year, lower than the corrosion rate of the DC-anodized specimen at 0.00197 mm/year. These findings indicate that AC anodization on stainless steel offers advantages in terms of higher current density, phase transformation, and lower corrosion rate compared to DC anodization. These results highlight the need for further investigation and exploration of AC anodization as a promising technique for enhancing the electrochemical properties of stainless steel.
  • Publication
    Hydrogen Evolution Reaction of AC Anodized Stainless Steel 304L
    A novel method of anodizing stainless steel (SS) 304L with alternating current (AC) as the power source is presented in order to generate a porous oxide layer. This study aims to investigate the influence of AC anodizing of SS304L on hydrogen evolution reaction (HER) activity and characterize the morphology of oxide film formed. The AC anodization method was carried out using an AC power source in a solution of ammonium fluoride, NH4F, water, H2O and ethylene glycol at room temperature, with anodizing time ranging from 10 to 50 minutes. Scanning electron microscope (SEM) and a 3D profiler were used to characterize the surface morphology, and a potentiostat is used to study the behaviour of the HER. The results show that the oxide film gradually covered the SS304L surface and fully covered at 30 minutes anodizing time, then begin to crack at 40 and 50 minutes. The thickness of the layer reached its maximum at 5248.67 nm with pore size of 380.13 nm after 30 minutes and then gradually began to decrease. Notably, the lowest HER activity, measuring -426.58 mV, was detected after 30 minutes. These findings clarified the relationship between the AC anodizing time, oxide film morphology, and HER activity, making it easier to optimize stainless steel 304L for enhanced hydrogen evolution applications.
  • Publication
    Oxide Film Formation on Stainless Steel 304L by Anodizing Method with Different Power Sources
    In order to generate a nanoporous oxide film, stainless steel 304L is anodized using an alternating current (AC) and direct current (DC) source in an ethylene glycol solution containing ammonium fluoride, NH4F, and water, H2O. This study focuses on the differences between AC and DC anodizing in terms of current density versus time response, thickness, and depth of the oxide film formed on the anodized specimens, surface roughness, and element composition of the specimens because there is limited study on AC anodizing of stainless steel. In 0.5% of 0.3M NH4F and 3% H2O in ethylene glycol solution, the AC and DC anodizing are conducted for 30 minutes at voltages ranging from 30V to 50V and 21.2 V to 35.4 V, respectively. The current density versus time response revealed that AC anodizing produced more current density than DC anodizing. As for the thickness and depth of the generated oxide films, only the specimens that have been anodized in AC indicated an increase in these films, whereas specimens that have been anodized in DC showed the metal dissolving as the specimens degraded. The surface roughness of AC anodized specimens reduced with increasing anodizing voltage, whereas DC anodized specimens increased with increasing anodizing voltage. The element composition of the anodized specimens revealed that the mass percentage of oxygen, O element is higher for AC anodized specimens compared to DC specimens. This suggests that AC anodizing on stainless steel might offer important advantages and should be further researched.
  • Publication
    Impact of AC Anodizing on SS304L Oxide Film and Its Effect on Hydrogen Evolution Reaction (HER) Properties
    The effect of AC anodizing on the formation of oxide film on stainless steel 304L (SS304L) surfaces and its influence on the hydrogen evolution reaction (HER) were studied in this study. The SS304L specimens were prepared before being anodized for 30 minutes at various voltages (range from 10 V to 50 V) using an AC power supply at room temperature. The surface morphology is studied using scanning electron microscope (SEM) and 3D profilometer. A potentiostat is used to run linear sweep voltammetry (LSV) and Tafel analysis for the HER characterization. The result recorded the highest thickness of 9273.45 nm at 40 V anodizing voltage and the lowest surface roughness of 837.16 nm recorded at 50 V. The linear sweep polarization test solution exhibited the lowest overpotential at 50 V, 398.3 mV and a Tafel slope of 196 mVdec-1. These findings provide insight on the possibility of AC anodizing for improving the surface characteristics of SS304L for use in energy conversion applications.
  • Publication
    THE MORPHOLOGY AND ELECTROCHEMICAL STUDIES OF AC ANODIZED SS304L UNDER VARIOUS ANODIZING CONDITIONS
    A novel method of anodizing stainless steel (SS) 304L with alternating current (AC) as the power source is presented in the interest of producing a porous oxide film. Since there is a scarcity of research on AC anodizing, this research work is focused on the electrochemistry and morphology of the oxide film generated on the SS304L. The anodizing is done in an ethylene glycol solution containing different concentrations of ammonium fluoride, NH4F, varying from 0.5 wt.% to 7 wt.%. The anodizing voltage is fixed to 40 V and the process is carried out at 25oC for 30 minutes. The electrochemical studies using the Tafel polarization method in terms of corrosion rate showed decreased values from 0.2842 mm/year to 0.1026 mm/year of the as-received, and anodized 3.0 wt.% specimens, respectively. For morphological studies, the oxide film formed on the anodized SS304L is characterized using a scanning electron microscopy (SEM) and the thickness of the oxide film formed is recorded using 3D profilometer. The morphology demonstrated the formation of the porous arrangement with localized parts of the surface oxide layer and the thickness of the oxide film rises at 2.65 µm and 4.29 µm, respectively, when the NH4F concentration increases from 0.5 wt.% to 1.0 wt.%. This indicates that there are significant advantages of using AC anodizing on stainless steel.