Enhanced Corrosion−Resistance of AlTiCrFeMoSi High−Entropy Alloy Coating by Magnetron Sputtering

Round 1

Reviewer 1 Report

This work is devoted to an urgent task - the making of new anticorrosion coatings based on alloys with high entropy, resistant to liquid metal coolants for reactors. The data obtained are of interest to a wide range of readers. However, there are a number of caveats to the presentation of the data.

Namely:

1. It is worth describing the coating technique in more detail. To do this: a.) in the text of the article or the file "supplementsry materials" it is desirable to provide a picture with the target constructor and indicate its dimensions; b.) clarify whether it was DC- or RF- sputtering

2. The authors give the nanohardness for the substrate and for the coating with a sufficiently high accuracy - 3.284 and 11.881 GPa, respectively (lines 164 and 165). However, only one curve is shown in Fig. 4. This raises questions: how many samples were examined in total, were any statistical data obtained, and what is the error in determining the values ​​you indicated?

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Review comments on Coatings-2163443

In this work, the authors studied the corrosion-resistance of high-entropy alloy (HEA) coatings when they are exposed to a static liquid lead-bismuth eutectic (LBE). HEA coating was deposited on T91 substrates via magnetron sputtering. It is my recommendation that the current form of manuscript cannot be accepted for publication in Coatings due to following reasons,

1.       The experimental observations were not validated or compared with those reported in the literature. It is difficult to quantify the corrosion-resistance based on the SEM images presented in this study. Detailed description on Fig 5 and 6 should be added, especially for the marking within the images. Except in the Introduction section, no references were cited in the other sections of manuscript.

2.       The nanoindentation results for coatings are missing. The description on indenter tip used, applied loading mode should be included. The method for calculating hardness and elastic modulus should be described. Since T91 is well known metal, its properties should be compared with those reported in the literature. Fig. 4 should be enhanced with coating results. If maximum indentation depth is fixed as 200nm, how maximum load can be fixed as 700mN?

3.       Investigating the corrosion-resistance and mechanical properties of HEA coatings with different thickness (only one thickness is studied) are suggested for a comparative study.

4.       Fig. 1 should be enhanced with more detail. The cross-sectional SEM image of coated specimen is not clear (Fig. 3a). It is suggested to explain each image both in text and figure caption.

5.       How was the surface of the substrate (T91) prepared?

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The authors substantially revised the manuscript based on reviewer suggestions. The manuscript can be accepted for publication in Coatings after few minor revisions,

1. Regarding previous comment #2: The description on the nanoindentation experiments is not clear. In section 2, it was mentioned that maximum load is fixed as 700mN, however, in section 3.2, maximum indentation depth of 2000 nm was applied. The nanoindentation load-depth curve for coating is missing. It is suggested to some nanoindentation study to descript the nanoindentation results

    [1] J. Mater. Res. Technol., 16 (2022) pp. 216-228

    [2] J. Mater. Res., 7 (1992), pp. 1564-1583

2. Page # line 182 -192: It is hard to understand the statement, which should be referred to the literature. 

Author Response

Dear Dr.Reviewer:

Thank you very much for your valuable comments. According your suggestion，the modify as follows:

Reply 1: The authors have carefully read the literature recommended by the reviewer. The maximum load of 700 mN described in the nanoindentation experiment is not a fixed load, but the maximum load of the nanoindenter equipment. The nanoindentation load-displacement curve of the coating is supplemented in the manuscript and a description of the nanoindentation results is added.

Reply 2: The authors have rewritten the line 182-192 statement and cited relevant references.