Novel Features, Applications, and Recent Developments of High-Entropy Ceramic Coatings: A State-of-the-Art Review

Response to Reviewer 1 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Yes

Are the methods adequately described?

Yes

Are the results clearly presented?

Yes

Are the conclusions supported by the results?

Yes

3. Point-by-point response to Comments and Suggestions for Authors

Comment 1: What is the main aim of this review? Is it incremental to the existing reviews? why authors wanted to review this topic? clear statements are needed.

Response 1: Thank you for pointing this out. We agree with this comment. Therefore, we have explained the aim of the review clearly, as the exploration of high entropy ceramic coatings continues to be an active area of research, and this review can contribute to providing insight into their application potential and advancing the field of materials science and engineering. [The aim of the review is modified under section 1.1, page 4, and line 113 and updated in the manuscript]

Indeed, this review sheds light on the Novel Features, Applications, and Recent Developments of High-Entropy Ceramic Coatings, which will definitely benefit upcoming research and studies.

As the topic consists of high potential in terms of its application and modern science can benefit from it, the authors choose to contribute to the knowledge fraternity by reviewing this new and novel topic in detail. 

Comment 2: All or any of the author has expertise in this field?

Response 2: We are overwhelmed to have this comment, and with the positive note, we want to share that all the authors have clear knowledge and expertise in this field.

Comment 3: Authors should reformat the manuscript mainly by removing bullets in the text section 5 especially, subscripts in material formulas cited in references.

Response 3: Thank you for your emphathaize on this section and accordingly, all the bullet points are replaced with section numbers as 5.1, 5.2 ………. 7.3 in sections 5, 6, and 7 and updated in the manuscript, marked in red.

Comment 4: In Fig. 5, what are letters A to E? they were neither referred in the text nor described in the caption.

Response 4: Thank you for your in-depth perspective. The letters A to E describe the different distances between the substrate and the target of co-deposition. Various targets provide some different concentration gradients on the substrate during co-deposition to produce a HEA film which becomes a homogeneous concentration of film distribution. [Mentioned in Section 2, page 7 and line 252-255].

Comment 5: Fig. 5 is difficult to understand. General perspective is bulk to films for deposition or authors refer the composition? What does this arrow represent? Details are needed.

Response 5: Thank you for your kind emphathize on that figure. The arrows from the letters A to E describe the different distances between the substrate and the target of co-deposition.

The combination of high-throughput characterization techniques helps to achieve rapid screening of HEAs, followed by the bulk-like selected components. As per the design requirements of HEAs, alloy or single-element targets can be prepared, and this is controlled by the atomic percentages of elements.

[Mentioned in Section 2, page 7 and line 257-260].

Comment 6: In references, new references after 2020 are not listed. Hence, recent literature is required for the readers to understand state of the art.

Response 6: Thank you for your clear mention and highlight of the importance of relevant new references in a review journal. New references after 2020 have been incorporated in the revised manuscript in place of Ref. 100, 106-111, 163, 164 and 177, as those provide similar types of impression.  

Response to Reviewer 2 Comments

1. Summary

Thank you very much for taking the time to review this manuscript. Please find the detailed responses below and the corresponding revisions/corrections highlighted/in track changes in the re-submitted files.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

Does the introduction provide sufficient background and include all relevant references?

Yes

Are all the cited references relevant to the research?

Yes

Is the research design appropriate?

Yes

Are the methods adequately described?

Yes

Are the results clearly presented?

Yes

Are the conclusions supported by the results?

Yes

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: I recommend making the abstract more specific and transferring all abbreviations to the introductory section of the paper. Clearly highlight the research objective.

Response 1: Thank you for pointing this out. We agree with this comment and as per that the manuscript has been modified and all the abbreviations are mentioned in the introduction section and removed from the abstract section.  Research objective is clearly highlighted as the exploration of high entropy ceramic coatings continues to be an active area of research, and this review can contribute to provide an insight to their application potential and advancing the field of materials science and engineering. [The aim of the review is modified under section 1.1, page 4, and line 113 and updated in the manuscript]

Comments 2: Explain the importance of HEA alloys. The resolution of the images and diagrams is not satisfactory; some data are not readable.

Response 2: HEAs are recognized in the field of biomedical engineering, aerospace and energy sector for their exceptional mechanical strength, and corrosion resistance. [Added in introduction section, page 2, and line 58-60].

Figures 1, 2,3, 4 and 5 are improvised with more references.    

Comments 3: Provide a more detailed discussion of the potential applications of HECCs, as well as the fields in which they are used. Is it possible to include more detailed comparisons with cases involving other types of alloys?

Response 3: We are overwhelmed to have this comment. Potential applications are mentioned in section 6: Future Prospects and Applications.  

Comment 4: Clarify which problems are addressed by the presented research and highlight the scientific contribution of the work.

Response 4: Thank you for the emphasize on the point. Unlike previous reviews that focus on individual ceramic families, this article integrates the novel features, diverse applications, and recent developmental breakthroughs across carbides, nitrides, borides, and oxides to reveal the unifying principles governing configurational disorder, phase stability, and microstructure property relationships in HECCs.

Comment 5: In this regard, the paper lacks a more concrete discussion of the research results. For clearer presentation, consider using tables to compare different alloys.

Response 5: Thank you for your comments. In this revised manuscript various figures are incorporated for better understanding such as Fig 6.  

Comment 6: Some subtitles are not contextually aligned; it is necessary to connect the text into a coherent, logical whole.

Response 6: Thank you for your emphasize on theis matter. All the subtilltels are now contextually aligned.

Comment 7: Provide a more detailed description of the fabrication process; adjust Figure 4, present a simplified schematic, and specify the conditions during fabrication.

Response 7: We are overwhelmed to have this comment. Fabrication process is already menioned in section 2: Synthesis and Fabrication.

As per your suggestions Figure 4 is modified in the revised manuscript.

Comment 8: Information about the equipment and software used is missing.

Response 8: Thank you for you poiniting. As this is a review article, any equipment or software were not directly used in this manuscript.

Comment 9: Additionally, the paper should clearly state which problems are solved through the application of these coatings. Is it only friction and wear, i.e., issues related to mechanical losses? Emphasize the issue of mechanical losses as a problem that can be mitigated by coatings for sliding surfaces. From this perspective, include the work (Milojević, S., Savić, S., Mitrović, S., Marić, D., Krstić, B., Stojanović, B. i Popović, V. (2023). Solving the Problem of Friction and Wear in Auxiliary Devices of Internal Combustion Engines on the Example of Reciprocating Air Compressor for Vehicles. Tehnički vjesnik, 30 (1), 122-130. https://doi.org/10.17559/TV-20220414105757) in the literature section.

Response 9: Thank you for mentionaing the point. The application of HECC helps to address the problems related to mechanical, frictional and wear loses especially in the extreme environmental contions like in aerospace. It is mentioned in 5.3. Application in Extreme Environments.

The mentioned work is also added to this review article as per your suggestions in Ref 166.

Comment 10: Propose guidelines for future research, include a more comprehensive discussion, and expand the conclusions.

Response 10: Thank you for pointing out this. The path of future research is mentioned in section 6: Future Prospects and Applications.