Academia.eduAcademia.edu

Figure 2 – uploaded by Tapan Rout

See full PDFdownloadDownload figure
The surface morphology of the anodized steel was investigated using FEGSEM. The SEM images of steel anodized for 30 and 240 min are shown in Figures 1 and 2, Figure 1. SEM images of nanostructured steel which has been anodized for 30 min at various magnifications of (a) 10k X, (b) SOk X, (c) 100k X, and (d) 200k X.

Figure 1 The surface morphology of the anodized steel was investigated using FEGSEM. The SEM images of steel anodized for 30 and 240 min are shown in Figures 1 and 2, Figure 1. SEM images of nanostructured steel which has been anodized for 30 min at various magnifications of (a) 10k X, (b) SOk X, (c) 100k X, and (d) 200k X.

Related Figures (14)

"Energy Research Laboratory (ERL), Department of Chemistry, Loughborough University, Loughborough LE11 3TU, United Kingdom *Swinden Technology Centre, TATA Steel R&D, Moorgate, Rotherham S60 3AR, United Kingdom ‘New Technology Developments & Strategy Planning Research & Development Division, TATA Steel Ltd., Jamshedpur 831007, India
"Energy Research Laboratory (ERL), Department of Chemistry, Loughborough University, Loughborough LE11 3TU, United Kingdom *Swinden Technology Centre, TATA Steel R&D, Moorgate, Rotherham S60 3AR, United Kingdom ‘New Technology Developments & Strategy Planning Research & Development Division, TATA Steel Ltd., Jamshedpur 831007, India
Figure 2. SEM images of nanostructured steel that has been anodized for 240 min at various magnifications of (a) 1k X, (b) 10k X, (c) 50k X, (d) 100 k X, and (e) 200k X.
Figure 2. SEM images of nanostructured steel that has been anodized for 240 min at various magnifications of (a) 1k X, (b) 10k X, (c) 50k X, (d) 100 k X, and (e) 200k X.
Figure 3. XRD patterns of steel anodized for various times.
Figure 3. XRD patterns of steel anodized for various times.
Figure 4. XPS spectrum of 240 min anodized steel sample showing the (a) Fe and (b) O regions.
Figure 4. XPS spectrum of 240 min anodized steel sample showing the (a) Fe and (b) O regions.
Figure 5. Raman spectra of (a) 15, 30, and 45 min anodized steel; (b) 60, 120, 180, and 240 min anodized steel.
Figure 5. Raman spectra of (a) 15, 30, and 45 min anodized steel; (b) 60, 120, 180, and 240 min anodized steel.
Figure 6. SEM images at magnifications of (a) 50 kX and (b) 100 kX, to show the morphology of the material coated on the cathode during the anodization process (this image corresponds to the 240 min anodization process).
Figure 6. SEM images at magnifications of (a) 50 kX and (b) 100 kX, to show the morphology of the material coated on the cathode during the anodization process (this image corresponds to the 240 min anodization process).
higher frequencies. There seems to be no particular trend in the phase angle at low frequencies of 0.01 Hz, with the values averaging around 80° for anodization times between 0 to 120 min; however, it decreased to just above 60° for anodization times of 180 and 240 min. At higher frequencies (at around 10 Hz), a more clear trend in the phase angle can be identified. Generally, as the anodization time increases, the frequency at which the phase angle reaches an asymptotic value decreases. The trend of the time constant with the anodization time is shown in Figure 13. The time constant for plain (unanodized) steel is 0.12 ms, which then increased by a factor of 10, to 1.2 ms just by anodizing it for 15 min. The time constant increased linearly to around 25 ms as the anodization time is further increased to 60 min. Beyond this point, there is a sharp increase in the time constant to 80 ms for the electrode anodized for 120 min. This nonlinear behavior indicates that charging takes increasingly longer for longer anodization times. The time
higher frequencies. There seems to be no particular trend in the phase angle at low frequencies of 0.01 Hz, with the values averaging around 80° for anodization times between 0 to 120 min; however, it decreased to just above 60° for anodization times of 180 and 240 min. At higher frequencies (at around 10 Hz), a more clear trend in the phase angle can be identified. Generally, as the anodization time increases, the frequency at which the phase angle reaches an asymptotic value decreases. The trend of the time constant with the anodization time is shown in Figure 13. The time constant for plain (unanodized) steel is 0.12 ms, which then increased by a factor of 10, to 1.2 ms just by anodizing it for 15 min. The time constant increased linearly to around 25 ms as the anodization time is further increased to 60 min. Beyond this point, there is a sharp increase in the time constant to 80 ms for the electrode anodized for 120 min. This nonlinear behavior indicates that charging takes increasingly longer for longer anodization times. The time
Figure 9. Plot of phase angle as a function of log frequency for nanostructured steel anodized for various times ranging from 0 to 240 min. Figure 10. Capacitance as a function of log frequency for nanostructured steel anodized for various times ranging from 0 to 240 min.
Figure 9. Plot of phase angle as a function of log frequency for nanostructured steel anodized for various times ranging from 0 to 240 min. Figure 10. Capacitance as a function of log frequency for nanostructured steel anodized for various times ranging from 0 to 240 min.
Figure 8. Nyquist plots of nanostructured steel by anodization at various times ranging from 0—240 min (left). The graph on the right shows an expanded Nyquist plot in the high-frequency region.
Figure 8. Nyquist plots of nanostructured steel by anodization at various times ranging from 0—240 min (left). The graph on the right shows an expanded Nyquist plot in the high-frequency region.
Figure 11. Capacitance as a function of the anodization time of nanostructured steel at low frequency (0.01 Hz).
Figure 11. Capacitance as a function of the anodization time of nanostructured steel at low frequency (0.01 Hz).
Figure 13. Trend of the time constant as a function of the anodization time of the nanostructured steel. Figure 14. Stability test of 240 min anodized steel sample.
Figure 13. Trend of the time constant as a function of the anodization time of the nanostructured steel. Figure 14. Stability test of 240 min anodized steel sample.
Figure 12. Imaginary component of the capacitance as a function of log), frequency for nanostructured steel anodized for various times ranging from 0-240 min (left). The graph on the right shows only the 0—120 min anodization for clarity. The maxima can be used to determine the time constants (t = 1/fimax)-
Figure 12. Imaginary component of the capacitance as a function of log), frequency for nanostructured steel anodized for various times ranging from 0-240 min (left). The graph on the right shows only the 0—120 min anodization for clarity. The maxima can be used to determine the time constants (t = 1/fimax)-
Related topics:
Chemical Engineering
580 California St., Suite 400
San Francisco, CA, 94104
© 2025 Academia. All rights reserved