Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

Your manuscript presents interesting premises and contributes valuably to the field. However, some significant revisions are required to meet the publication standards. These necessary amendments have been detailed in the attached review. I encourage you to address these points thoroughly to enhance the clarity and reliability of your findings.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

- The authors should mention what was the purpose of using Al2O3 balls as sliding counter body.

- The authors mentioned that the working condition exerts an important influence on the tribological properties of the protective coatings, thus affecting the wear resistance of the workpieces. Still, they did not mention any specific application, which needs to be mentioned.

- Consequently, to the previous point, the authors must mention the contact pressures of the system, corresponding to each load.

- The authors should consider changing the analysis of results from section 3.3.3. in a clearer way instead of the method of response surface methodology.

- The conclusions of the work should be deepened, including the possible application in a specific workpieces application.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents new experimental results of studying the tribological properties of multilayer structures of TiAlSiN protective coatings on a WC-Co substrate.

TiAlSiN coating with hardness-modulated sublayers were deposited on the surface of WC-Co substrates by the technique of plasma immersion ion implantation and deposition (PIIID).

The new results presented in the manuscript complement previously performed studies, the results of which were published by the authors in 2009 and 2020.

The results obtained showed a change in the wear pattern depending on the normal load and velocity and made it possible to optimize the wear resistance of the TiAlSiN multilayer coating under certain combinations of normal load and velocity. To increase wear resistance, a combination of harder and lubricated sublayers with a reduced coefficient of friction and wear rate has been proposed.

In this case, protection of the coating from wear is achieved. Larger and harder abrasives have been shown to accelerate the wear process at higher displacement rates in the contact zone.

The manuscript needs minor revisions:

1) Line 176.  In Table 3, the authors indicated the concentrations of chemical components in the coating sublayers (A and B). Probably average concentrations are indicated. Confidence intervals for the obtained values should be provided according to the method and field emission scanning electron microscope used.

2) Line 186. In Table 4, the authors indicated the average values of hardness and Young's modulus. Confidence intervals for the obtained values must be provided. Would using the terms “nanohardness” or “microhardness” be more appropriate throughout the manuscript?

3) Line 230. Table 5 shows the content of elements inside and outside the wear marks. Confidence intervals for the obtained values must be provided. This information is important to confirm the accuracy of the values shown because the atomic fraction is reported with two significant figures after the decimal point. The reliability of the two significant figures after the decimal point is questionable.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

thank you for addressing my comments. The corrections made within the description of the experimental plan and the presentation of the 3D morphology results improve the understanding and perception of the paper. However, I still have comments on the research methodology adopted, especially in terms of assessing the effect of friction velocity on the wear of the tested coatings. I provide details in the appendix.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf