Effect of Laser Remelting of Fe-Based Thermally Sprayed Coating on AZ91 Magnesium Alloy on Its Structural and Tribological Properties

Round 1

Reviewer 1 Report

In this manuscript, Fe-based coatings were thermally-sprayed on the surface of AZ91 magnesium alloy by the HVOF method. Laser remelting treatment improved the hardness and wear resistance. Some of the results are interesting. My decision on the manuscript is a major revision, because the following issues must be addressed:

1.     The processing method used in the current manuscript is actually a combination of thermal spray and laser remelting, which is very similar to that in the following latest published papers: doi.org/10.1016/j.surfcoat.2023.129577. I suggest the authors to include them in the introduction, and make a brief comparison.

2.     The organization of the introduction can be improved. For example, for the summary of the methods used to improve wear resistance. Apart from the mentioned application of protective coatings, some other techniques like surface modification by grain refinement achieved by friction stir processing, which is a variant of friction stir welding (doi.org/10.1007/s00170-022-09793-x), and laser shot peening (https://doi.org/10.1016/j.triboint.2019.106138) are also advised to be summarized in the introduction.

3.     What is the advantage of thermally-HVOF-spray coating with laser treatment over direct laser cladding?

4.     The detailed process parameters of thermally-HVOF-spray should be listed.

5.     For the EBSD characterization, what is the used step size?

6.     Thickness of different samples were listed in Table 1, but analysis was not performed on this phenomenon.

7.     Please label austenite and carbide in Figure. 4. Also, please label fine carbide particles and carbides.

8.     On page 6 line 205, it was claimed ‘A high-magnification BSE SEM micrograph (Figure 5b,d) shows that the coating was fully crystallized after laser remelting. This was also confirmed by the EBSD analysis (see Figure 6a)’. It is lack of evidence for the conclusion that the coating was fully crystallized after laser remelting only from the EBSD results. Is it possible that amorphous phase existing in the as-sprayed coating also exists in the laser-remelted samples?

9.     Evidence or references are needed to support the statement ‘The EBSD results (Figure 6b) showed that the black areas are amorphous’. From my point of view, the black area can also be caused by poor sample preparation.

10.  The Conclusions can be more concise.

Author Response

Dear reviewer,

thank you very much and I appreciate your comments, which will lead to the improvement and increase the quality of the submitted paper.

I have commented on all your remarks (please see attached file). I have listed the individual comments in the attachment and also in the revised manuscript. Added text and sections are highlighted in the revised manuscript.

I hope I have responded sufficiently to all your comments.

Thank you.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper presents an examination of how laser remelting affects Fe-based thermally-sprayed coatings on the surface of the AZ91 magnesium alloy. The article is intriguing, but there are areas that can be enhanced, including:

 

1.       Highlighting the novelty of the research in the abstract and introduction.

2.       Improving the clarity of Figure 3 (d).

3.       Clarifying Figure 7 (a).

4.       Rewriting the conclusion section in a more concise form.

5.       Consider incorporating FTIR analysis to enhance the characterization section.

Moderate editing of English language.

Author Response

Dear reviewer,

thank you very much and I appreciate your comments, which will lead to the improvement and increase the quality of the submitted paper.

I have commented on all your remarks (please see attached file). I have listed the individual comments in the attachment and also in the revised manuscript. Added text and sections are highlighted in the revised manuscript.

I hope I have responded sufficiently to all your comments.

Thank you.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

I recommend the publication of this work. 

minor revision