A Study of the Microstructure and Mechanical and Electrochemical Properties of CoCrFeNi High-Entropy Alloys Additive-Manufactured Using Laser Metal Deposition

Round 1

Reviewer 1 Report

In this work, the authors studied the microstructure, mechanical and electrochemical properties of additive manufactured CoCrFeNi high-entropy alloy. The HEA was fabricated with the employment of three different laser powers. This work is interesting and is suitable for publication in coatings after a few changes:

1) In the introduction, literature on CoCrFeNi and relevant HEAs based on cantor alloy fabricated by additive manufacturing is poor. Please expand this part.

2) Why did you select this specific HEA?

3) How does the change in the laser power affects the oxide content of the HEA? Calculate the oxide content in the different configurations.

4) What is the chemical composition of the HEA? Please add a table. Is it consistent in different areas of the sample? Expand the relevant discussion.

5) Expand table 5. Add more electrochemical values like Epit and ipass. This will help you expand the discussion.

6) On the conclusions authors claim that the HEA fabricated with a laser power of 1300 W has the best corrosion peformance. However, Fig15 shows that the 1600 W configuration had the noblest Epit. Additionally, Ecorr, icorr between 1300 and 1600 W are very similar.

Author Response

Thank you very much for taking the time to review this manuscript. Please see the attachment, and please find the corresponding revisions in the re-submitted files.

Author Response File: Author Response.docx

Reviewer 2 Report

The authors have carried out a comprehensive study of the CoCrFeNi high entropy alloy prepared by additive manufacturing using laser. The authors varied the laser power to observe its effect on the HEA system's mechanical, electrochemical and other physical properties. There are minor questions as follows:

1.  The microstructures in Figure 6 look porous, and the pore size varies with laser power. What is your explanation?

2. Does the EBSD grain size in Table 3 tally with the Figure 5 optical micrograph data?

3. Please correct the figure numbers in fig. 10

4. Figure 11a abscissa shows 'distance from top' but the figure caption says 'inward from the surface.' Are they same?

5. Electrochemical tests show the stability of dense passive film at 1300 W laser power. How do we determine the chemical nature (metal oxide and hydrides) of this film?

The manuscript is otherwise accepted for publication.

English is acceptable

Author Response

Thank you very much for taking the time to review this manuscript. Please see the attachment, and please find the corresponding revisions in the re-submitted files.

Author Response File: Author Response.docx