Advantages of Electrochemical Polishing of Metals and Alloys in Ionic Liquids
Round 1
Reviewer 1 Report
We have been very helpful and grateful for your insightful considerations on electrochemical polishing. We have described some questions and what needs to be corrected as follows.
1. Line 55
Please check the next sentence again and rewrite it. "When the wavelength of the visible light is near or greater than the sizes of asperities, the metal surface becomes dull."
2. Lines 206-208
The picture in Figure 3 is difficult to distinguish between the presence or absence of electropolishing. Is it possible to improve the picture quality? Or is it possible to substitute photos of other references?
3. Can you explain the existing problems with electropolishing using lonic liquids and how to improve them in the future?
Author Response
Response to Reviewer 1
We would like to thank the reviewer for the careful reading of our manuscript and the questions, remarks, and recommendations. We have revised and expanded the manuscript. Please find below our responses to the reviewers comments. All significant changes in the manuscript are highlighted in yellow. Also, we checked the use of English and made corrections in the text (not shown in the revised manuscript).
Comment 1. Line 55
Please check the next sentence again and rewrite it. "When the wavelength of the visible light is near or greater than the sizes of asperities, the metal surface becomes dull."
Response: This was corrected as follows: "When the wavelength of the visible light is near or greater than the sizes of asperities, the metal surface seems dull."
Comment 2. Lines 206-208
The picture in Figure 3 is difficult to distinguish between the presence or absence of electropolishing. Is it possible to improve the picture quality? Or is it possible to substitute photos of other references?
Response: This was corrected: Figure 3 has been removed.
Comment 3. Can you explain the existing problems with electropolishing using lonic liquids and how to improve them in the future?
Response: The following paragraph was added in the Conclusions:
“There are several barriers to commercialization of ionic liquids as to the electropolishing application, including [73]:
- A rather high cost of the chemicals used to prepare ionic liquids,
- The need to establish compliance with existing and planned environmental regulations,
- The processes are not optimized.
However, these are temporary barriers that can be overcome in the near future taking into account the unique advantages of these benign electrolytes in this particular application as well as the economy of materials that are otherwise lost as scale in the case of mechanical polishing.”
Reviewer 2 Report
The manuscript concerns a literature review on electrochemical polishing of metals in ionic liquids.
The manuscript takes up an interesting topic, it is well prepared.
I only miss a few new publications (2020, 2021) that have been omitted from this work.
When entering the temperature in Celsius degrees, please add a space between the value and the degree sign. please correct throughout the manuscript.
Some of the figures presented are poor quality (especially Fig. 3), could the authors post better quality figures (ask authors/publishers for original files)?.
Author Response
Response to Reviewer 2
We would like to thank the reviewer for the careful reading of our manuscript and the questions, remarks, and recommendations. We have revised and expanded the manuscript. Please find below our responses to the reviewers comments. All significant changes in the manuscript are highlighted in yellow. Also, we checked the use of English and made corrections in the text (not shown in the revised manuscript).
Comment 1: The manuscript concerns a literature review on electrochemical polishing of metals in ionic liquids. The manuscript takes up an interesting topic, it is well prepared. I only miss a few new publications (2020, 2021) that have been omitted from this work.
Response: This was corrected. The list of references has been updated. A few recent publications have been added.
Comment 2: When entering the temperature in Celsius degrees, please add a space between the value and the degree sign. please correct throughout the manuscript.
Response: This was corrected.
Comment 3: Some of the figures presented are poor quality (especially Fig. 3), could the authors post better quality figures (ask authors/publishers for original files)?
Response: This was corrected: Figure 3 has been removed.
Reviewer 3 Report
The authors' idea of conducting a review on the advantages that electrochemical polishing of metals by using ionic liquids can offer is remarkable.
Unfortunately, there are too few bibliographic references for a review, in the situation where there are many concerns of researchers in this field.
However, several points need to be addressed prior to publication of this manuscript. My comments/suggestions are given:
- Line 29 “There are various industrial applications requiring particular quality of the metallic surface”. Give examples with bibliographic references.
- Line 33 “Anodization of metals and alloys was studied in details in aqueous solutions of various electrolytes [8]”. At least a few examples need to be mentioned. These must be here and not in the paragraph between lines 112-115 and must also be completed.
- Chapter 2 is called Electropolishing mechanics. Is this issue being addressed? Isn't it about mechanisms?
- Lines 82-105. Too much data on electropolish in aqueous solutions. The proposed topic refers to Electrochemical Polishing of Metals in Ionic Liquids. This topic needs to be discussed.
- The authors need to talk more about the properties of ionic liquids, about the types of ionic liquids, etc.
- Lines 125-127 “Electropolishing efficiency is dependent on the chemical properties of the films, which are known to be individual for each metal or alloy. In general, the mechanism of metal surface electropolishing implies the discrepant rates of the removal of covering films and proper metal atoms from different sites of the surface.” The authors must give concrete examples, introduce diagrams so that they can support these statements.
- The optical micrographs in Figure 3 are not the best choice. They have no clarity or scale. Authors should look in the literature there may be other references besides 35.
- What are references 36 and 37 looking for in the paragraph between lines 213-216? In this reference the authors discuss Pt and Ti, and here the subchapter refers to steel?
- The subchapter in which Pt is discussed must be extended, especially since the authors have published works on this subject. More examples, images, etc.
- Most references appear in the subchapter assigned to nickel, but there is just some information extracted from these references! Please complete this subchapter!
- Also, the subchapter about silver should be completed because in the literature there is more information in various bibliographical references.
Author Response
Response to Reviewer 3
We would like to thank the reviewer for the careful reading of our manuscript and the questions, remarks, and recommendations. We have revised and expanded the manuscript. Please find below our responses to the reviewers comments. All significant changes in the manuscript are highlighted in yellow. Also, we checked the use of English and made corrections in the text (not shown in the revised manuscript).
General comments:
The authors' idea of conducting a review on the advantages that electrochemical polishing of metals by using ionic liquids can offer is remarkable. Unfortunately, there are too few bibliographic references for a review, in the situation where there are many concerns of researchers in this field.
Response: This was corrected. The list of references was supplemented by 11 papers, most of them released in 2019-2021. The manuscript has been updated accordingly to discuss the results of these recent publications. The additions are highlighted in yellow.
Specific comments: However, several points need to be addressed prior to publication of this manuscript. My comments/suggestions are given:
Comment 1: Line 29 “There are various industrial applications requiring particular quality of the metallic surface”. Give examples with bibliographic references.
Response: The needed examples are given for each metal all over the manuscript, e.g., see lines 144-148 (steels), Section 3.2 first paragraph (titanium), Section 3.9 first paragraph (silver).
Also, we may suggest to include the following references in the review if the reviewer will recommend, although they are short reviews published quite some time ago:
- Benaben, P. Are Ionic Liquids the Future of the Surface Treatment? Products Finishing Magazine / pfonline.com 2013, https://www.pfonline.com/articles/are-ionic-liquids-the-future-of-the-surface-treatment.
- Collins, J. Electropolishing in Ionic Liquids - Prosurf 2016, https://www.yumpu.com/en/document/view/41192715/electropolishing-in-ionic-liquids-prosurf.
Comment 2: Line 33 “Anodization of metals and alloys was studied in details in aqueous solutions of various electrolytes [8]”. At least a few examples need to be mentioned.
…These must be here and not in the paragraph between lines 112-115 and must also be completed.
Response: Electrochemical processes in aqueous solutions are not the subject of this review. There are a lot of published reviews concerning anodization in aqueous solutions. Numerous examples can be found in ref. 8.
Lines 112-115 do not refer to the examples of anodization but to the common applications of metal polishing.
Comment 3: Chapter 2 is called Electropolishing mechanics. Is this issue being addressed? Isn't it about mechanisms?
Response: Yes, it is reasonable to substitute mechanics for mechanisms.
Comment 4: Lines 82-105. Too much data on electropolish in aqueous solutions. …
Response: Electropolishing in ionic liquids is connected with that in aqueous solutions of electrolytes. To elucidate the advantages of ionic liquids, one should compare the electropolishing features in various media. Just for this reason, the accepted mechanism of electropolishing in aqueous solutions is considered in details in lines 82-105.
Comment 5: …The proposed topic refers to Electrochemical Polishing of Metals in Ionic Liquids. This topic needs to be discussed.
Response: The answer to this comment is considered below (line 133).
Comment 6: The authors need to talk more about the properties of ionic liquids, about the types of ionic liquids, etc.
Response: These issues are well covered by many reviews and books, most important of them have been cited in the review.
Comment 6: Lines 125-127 “Electropolishing efficiency is dependent on the chemical properties of the films, which are known to be individual for each metal or alloy. In general, the mechanism of metal surface electropolishing implies the discrepant rates of the removal of covering films and proper metal atoms from different sites of the surface.” The authors must give concrete examples, introduce diagrams so that they can support these statements.
Response: Electropolishing of metals includes only two electrochemical processes: (1) the removal of the oxides or films of other compounds and (2) the removal of the metal from metal roughness and no other processes. Some examples are given for supporting these common statements for each metal or alloy, for instance, in Section 3.2. “The authors studied in detail (cyclic voltammetry, XRF analysis) the mechanism…” or Section 3.4. “The data were presented by plots of the copper mass loss as functions of the quantity of electricity consumed. According to the results obtained, …”.
Comment 7: The optical micrographs in Figure 3 are not the best choice. They have no clarity or scale. Authors should look in the literature there may be other references besides 35.
Response: This was corrected: Figure 3 has been removed.
Comment 8: What are references 36 and 37 looking for in the paragraph between lines 213-216? In this reference the authors discuss Pt and Ti, and here the subchapter refers to steel?
Response: Unfortunately, there are yet no data dealing with polishing of steels in ionic liquids based on imidazolium, pyridinium or related cations. The references 15, 36, 37 are related to electrochemical polishing of other metals and alloys rather than steels for which this type of ionic liquids was not used. This paragraph is a reasonable transition to the metals the polishing of which was carried out not only in Ethaline but also in other media. That is why these references have been included in the paragraph between lines 213-216.
Comment 9: The subchapter in which Pt is discussed must be extended, especially since the authors have published works on this subject. More examples, images, etc.
Response: The reviewer is absolutely right. Polishing of Pt is really considered in our work. However, we believe that there is no serious reason to exaggerate our results in order not to change the balance between all cited works. We also think that the cited data are quite sufficient for this review.
Comment 10: Most references appear in the subchapter assigned to nickel, but there is just some information extracted from these references! Please complete this subchapter!
Response: We agree with the reviewer and some additional information is included.
Comment 11: Also, the subchapter about silver should be completed because in the literature there is more information in various bibliographical references.
Response: We agree with the reviewer and some additional information is included.
Round 2
Reviewer 3 Report
Based on a very good idea, the manuscript is now a well structured form. As the authors have made all the required corrections and completions, I believe that the manuscript can be published in its current form.
