Low-Potential Zone at the Interface of Precipitate and Austenite Affecting Intergranular Corrosion Sensitivity in UNS N08028 Nickel–Iron–Chromium Alloy
Round 1
Reviewer 1 Report
IGC is still an interesting topic especially for NIckel alloys, therefore the results are relevant for the community.
Some topics has to be improved:
- Mention the scan rate of the anodic polarization curves
- Mention the amplitude of the EIS measurements
- Correct the graphs in fig 3: not counts but mV at the y-axis
- The EIS spectra need the same scaling on Z´and Z´´ to detect semi circles (Fig. 4)
- some typing errors "volt" instead of volta are in the text
Author Response
Dear reviewer:
We have made corresponding modifications to your comments, and the modifications are as follows:
1)Mention the scan rate of the anodic polarization curves?
Answer:The scanning rate of the anode polarization curve is 30mV/min.
2)Mention the amplitude of the EIS measurements?
Answer:The frequency range of electrochemical impedance test was 10-1~105Hz, and the amplitude was 10mV. Polarization curve test potential range of -0.5~1.2V (SCE). The EIS test range is: High Frequency (Hz) = 1e+5,Low Frequency (Hz) = 0.01
3) Correct the graphs in fig 3: not counts but mV at the y-axis
Answer:Some errors and corrections in coordinates:
y-axis："count"→ "Potential(mV)"；
x-axis："Position/um"→"Position（μm）"
In addition, the image format has been adjusted to avoid the problem of overlapping images.
4) The EIS spectra need the same scaling on Z´and Z´´ to detect semi circles (Fig. 4)
Answer:The axes of the Nyquist diagram are modified to the same scale: 2000.
5) some typing errors "volt" instead of volta are in the text
Answer:In the article "Volt" changed to "Volta"
Reviewer 2 Report
The article appears to be well organized and the experimental information is clear. Experimental methods are also described clearly.
However, there is one part ( The effect of different Volta potentials on ion migration in passive films) where the data and discussion is the repetition of what has been previously reported by the group.
I consider it important to modify or change the theoretical discussion as this could represent a potential source of plagiarism.
I would recommend and careful major revision and a warning to the authors about the implications of duplicated information in the manuscript.
Minor:
Figure 2. The figure lacks quality and scale bars are not centered within the pane
Figure 3. The layout is not clear and images seem to overlap
Figure 4. There are errors in the labeling
Figure 6. The image corresponds to a previous work, if the calculations were made specifically for this manuscript, details of the calculation must be attached in its corresponding section
Figure 7. It is hard to read units in many plots. For example, x: Temperature, are units T/K? Clarify and correct
Author Response
Dear reviewer:
We have made corresponding modifications to your comments, and the modifications are as follows:
1)Figure 2. The figure lacks quality and scale bars are not centered within the pane.
Answer:The figure in Figure 2 has been adjusted: Move the scale to the center of the window as recommended. And change the ordinate, change the "Count" to "Conten(wt%)".
2) Figure 3. The layout is not clear and images seem to overlap.
Answer:Some errors and corrections in coordinates:
y-axis："count"→ "Potential(mV)"；
x-axis："Position/um"→"Position（μm）"
In addition, the image format has been adjusted to avoid the problem of overlapping images.
3) Figure 4. There are errors in the labeling.
Answer:The axes of the Nyquist diagram are modified to the same scale: 2000.In addition, In Figure 4 (a), the horizontal and vertical coordinates are modified respectively:log(I/A)→log(i, A·cm-2)，Potential/V→E (V vs. SCE)；In Figure 4 (b), the horizontal and vertical coordinates are modified respectively:-Z''/ohm→-Z''(Ω·cm2)，Z'/ohm→Z'(Ω·cm2).
4) Figure 6.The image corresponds to a previous work, if the calculations were made specifically for this manuscript, details of the calculation must be attached in its corresponding section.
Answer:FIG. 6 shows the atomic model based on point defect model (PDM) proposed by our research group in the previous work, which describes the process of vacancy migration. On this basis, the effects of precipitated phase and electric field on ion migration and diffusion coefficient in passivated films are further discussed. This modification has been redrawn with reference to the original drawing.
5) Figure 7. It is hard to read units in many plots. For example, x: Temperature, are units T/K? Clarify and correct.
Answer:After verification, the horizontal coordinate of FIG. 7 is changed to Temperature(℃)
Reviewer 3 Report
Dear authors, once the manuscript was reviewed, this reviewer found some points that should be clarified.
1. In “The test material was a UNS N08028 nickel-base alloy, and its composition is shown 82 in Table 1”.
Ø Is it possible to define this alloy as Ni-base alloy when the majority element is Fe?
Ø There is much literature where the UNS N08028 alloy is defined simply as “stainless steel”, “highly alloyed Steel”, “superaustenitic stainless steel”, “highly alloyed austenitic stainless steel” or “Incoloy 28”, but not Ni-base alloy.
Ø It is important to clarify this confusion, otherwise the title of the manuscript and the entire document where the phrase "Ni-base alloy" appears must be modified.
2. The authors must specify in which type of atmosphere the heat treatments were carried out.
3. In figure 4, the axes of the Nyquist diagram must have the same scale, for example 2000 and 2000. Also, in the experimental procedure the area of the working electrodes must be specified.
4. In figure 4, both graphs should be expressed per unit area, that is, A/cm2, ohm-cm2.
5. In “3.4. The effect of different Volta potentials on ion migration in passive films”, the analysis is very interesting.
Ø However, I believe that in order to strengthen the hypothesis of the Cr2O3/Cr(OH)3 double layer passive film, the authors should present the Bode diagrams, after 72 hours of immersion.
Ø In the Bode plots the high frequency plateau should develop at frequencies above 1000 Hz, and the phase angle would also tend to zero at frequencies above 1000 Hz.
Author Response
Dear reviewer:
We have made corresponding modifications to your comments, and the modifications are as follows:
1) In “The test material was a UNS N08028 nickel-base alloy, and its composition is shown 82 in Table 1”.
Answer:Based on your suggestions and literature research, we first modify the nickel base alloy in the article to UNS N08028 Nickel Iron Chromium Alloy.
2) The authors must specify in which type of atmosphere the heat treatments were carried out.
Answer:Heat treatment is carried out in an oxygen environment in a Muffle furnace.
3) In figure 4, the axes of the Nyquist diagram must have the same scale, for example 2000 and 2000. Also, in the experimental procedure the area of the working electrodes must be specified.
Answer:The axes of the Nyquist diagram are modified to the same scale: 2000.The working electrode area for the experiment is 1 cm2
4) In figure 4, both graphs should be expressed per unit area, that is, A/cm2, ohm-cm2.
Answer:In Figure 4 (a), the horizontal and vertical coordinates are modified respectively:log(I/A)→log(i, A·cm-2)，Potential/V→E (V vs. SCE)；In Figure 4 (b), the horizontal and vertical coordinates are modified respectively:-Z''/ohm→-Z''(Ω·cm2)，Z'/ohm→Z'(Ω·cm2).
5) In “3.4. The effect of different Volta potentials on ion migration in passive films”, the analysis is very interesting.
Answer:We add Bode logarithmic amplitude-frequency characteristic curve and Bode logarithmic phase-frequency characteristic curve to the original drawing.
Reviewer 4 Report
In my opinion, the article is written in good scientific language, the thoughts are clearly stated. I have no major comments.
You just need to organize the bibliography according to the requirements: in most sources, only the authors, year and publisher are specified. No titles, incomplete bibliography.
Author Response
Dear reviewer:
We have made corresponding modifications to your comments, and the modifications are as follows:
1）You just need to organize the bibliography according to the requirements: in most sources, only the authors, year and publisher are specified. No titles, incomplete bibliography.
Answer:In response to your suggestions regarding references, we have made the following changes to the format, for example:
- B. Gwinner, M. Auroy, F. Balbaud-Célérier, P. Fauvet, N. Larabi-Gruet, P. Laghoutaris and R. Robin, Corros. Sci., 107 (2015) 60.
→
- 2.Gwinner, B.; Auroy, M.; Balbaud-Célérier, F.; Fauvet, P.; Larabi-Gruet, N.; Laghoutaris, P.; Robin, R. Towards a reliable determination of the intergranular corrosion rate of austenitic stainless steel in oxidizing media. Corros Sci. 2016, 107, 60-75.
