Effect of W Content on Microstructure and Properties of Laser Cladding CoCrFeNi HEA Coating

Round 1

Reviewer 1 Report

The paper is very original and very interesting.

The authors adopted the appropriate research methodology.

 Analysis and interpretation of the obtained research results at a very good substantive level.

The paper was written correctly.

The language of the paper is satisfactory.

The authors drew the correct conclusions from the obtained research results.
The paper meets the journal's requirements and can be published.

Author Response

Thank you for your approval of this manuscript, thank you.

Reviewer 2 Report

The article describes studies of the influence of W on the properties of CoCrFeNi HEA coating. The article is devoted to a topic that is very popular among researchers and will be useful to readers of the journal.

I have a few questions and comments for the authors:

1. The article does not indicate the chemical composition of the CoCrFeNi HEA alloy.

2. For comparison, it would be more correct to indicate not only the hardness and corrosion properties of 316L steel, but also CoCrFeNi HEA without W. What properties does CoCrFeNi HEA coating have?

3. It would be useful to show not only the average hardness of the coatings, but also the distribution of hardness over the cross section of the section, i.e. show the change in hardness from the surface to the base steel (316L), the transitional fusion zone and the heat affected zone.

4. What was the purpose of introducing W? What properties of CoCrFeNi HEA coating did not satisfy?

Author Response

Reviewer 2：The article describes studies of the influence of W on the properties of CoCrFeNi HEA coating. The article is devoted to a topic that is very popular among researchers and will be useful to readers of the journal.

Response: Firstly, We are grateful for the recommendation of the reviewer to accept our manuscript. Thank you for your affirmation of this paper. Below we have revised and replied to your opinions one by one.

Following are my comments:

• The article does not indicate the chemical composition of the CoCrFeNi HEA alloy.

Response: We appreciate it very much for your advice! We have added the chemical composition of the CoCrFeNi HEA alloy in Table 2 according to the reviewer’s opinion. See the text for specific modifications.

2，For comparison, it would be more correct to indicate not only the hardness and corrosion properties of 316L steel, but also CoCrFeNi HEA without W. What properties does CoCrFeNi HEA coating have?

Response: Firstly, in the draft's Figures 7 and 8, we have provided information about the hardness and corrosion resistance of the pure CoCrFeNi HEA coating. Secondly, the CoCrFeNi coatings have good corrosion resistance properties, but their hardness is lower. The good corrosion resistance is described in the Introduction part of the article in lines 48-50, and we have added a description of the hardness in lines 80-82 of the article with references. See the text for specific modifications.

3，It would be useful to show not only the average hardness of the coatings, but also the distribution of hardness over the cross section of the section, i.e. show the change in hardness from the surface to the base steel (316L), the transitional fusion zone and the heat affected zone.

Response: In response to your suggestion, we have added the hardness distribution of the HEA/W composite coatings in Figure 7(a) so that you can understand the hardness variation from the surface to the base steel (316L), the transition fusion zone, and the heat affected zone.

4，What was the purpose of introducing W? What properties of CoCrFeNi HEA coating did not satisfy?

Response: In our previous study, it was found that the preparation of pure HEA coating on 316L substrate can enhance the corrosion resistance of the substrate, but the hardness of the coating is lower than 316L substrate. This limits the use of CoCrFeNi HEA coatings. The hardness of W particles is large. Therefore the aim of this study was to add different mass fractions of W particles to prepare HEA/W composite coatings and observe whether there is any enhancement in hardness and change in corrosion resistance, so that CoCrFeNi HEA coatings can be more widely used.

Reviewer 3 Report

In this study, the authors investigated the process of coating of HEA/W composite on 316L SS substrates with different mass fractions of W. Various characterization techniques have been performed to analyze the microstructure of the HEA/W composite coatings. Their results show that the W particles were uniformly distributed at the bottom of the coatings due to gravity and convection effects. The addition of large W particles to the HEA powder caused lattice distortion in the HEA, resulting in grain refinement. In my opinion the topic is relevant, the investigation is satisfactory and the manuscript well written. My question is that it would be great if the diagrams related to the distribution of CoCrFeNi HEA powder and the distribution of spherical W particles were added to Figure 1.

Author Response

Firstly, We are grateful for the recommendation of the reviewer to accept our manuscript. Thank you for your affirmation of this paper. We have added the particle size distribution diagram in Figure 1 according to the reviewer’s opinion. See the text for specific modifications.

Round 2

Reviewer 2 Report

The authors gave comprehensive answers to my questions. The article has been substantially corrected by the authors. I recommend an article for publication in a scientific journal in this version.