Effect of Gradient Multilayer Design on Tribological Performance of TiN/TiSiN Coatings Prepared by Cathodic Arc Ion Plating

Round 1

Reviewer 1 Report

The draft is well written, i suggest to address the following;

a) INTRODUCTION: Focus on the analysis/discussion of the modulation period (more details of each study you are reporting) and the effect on E and H, wear and the coating characteristics you are presenting and discussing. For instance, how is the modulation period conected to high H and E?.

b) EXPERIMENTAL; include a brief description of the method you applied for stress measurements,

c) Fig. 8b - it seem that the CrN/ZrN reference hast two symbols - the green inverted triangle appears to be a mistake.

The use of the word Literatures is a bit controversial. In your position i would used literature or other words that refer to plural such as references, publications, etc. Maybe look for other synonyms.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In the manuscript, the authors present an interesting study on tailoring mechanical properties and tribological characteristics of TiN/TiSiN coatings by applying a gradient multilayer design. The paper is well-written, pleasant to read, covers an attractive topic, and contains relevant references. Some minor points that escaped the authors’ attention can be clarified in the minor revision I am suggesting.

·         Title. I recommend adding the word “design” to improve the title: “Effect of gradient multilayer design on tribological performance of TiN/TiSiN coatings prepared by cathodic arc ion plating”.

·         Page 2, Line 4-5. In the sentence “The presence of amorphous SiNx phase can also increase the interfaces …” it is unclear how interfaces can increase. Probably authors meant the number of interfaces. If so, please consider modifying the sentence.

·         Page 2, Line 28. What does improving the interfaces mean? Please, clarify it.

·         Page 5, Line 3-4. “The worn surface depth and width of the coatings were character by…” is recommended to be modified as follows: “The depth and width of the worn surface were characterized by…”

·         Page 5, Lines 11 and 13. In line 11, there is written that “…peaks of TiN shifted to low angles…”. However, in line 13 authors mention the opposite: “Fig. 2 reveals a shift to higher diffraction angle for the coatings…” Looking at XRD patterns, it is clear that peaks were shifted to higher angles. Such contradictory statements must be carefully corrected.

·         Page 9, Line 14-15. The sentence “Under the action of load, coatings take place irreversible plastic deformation.” should be revised. For instance, irreversible plastic deformation takes place in the coatings.

·         Page 10. Figure 8. Since the mechanical properties of multilayer (M1-M6) and gradient multilayer (G2-G6) coatings are discussed in the present work, I recommend adding to Fig.8 also values of H, E*, H/E*, and H3/E* for regular multilayers M1-M6 to compare two different structure architectures.

·         Page 10, Line 26-27. Fig. 7c shows not similar but opposite trends for hardness values (G1 and G2 showed an ascending trend, while G3-G4 and G5-G6 showed a descending trend). The sentence should be checked.

·         Page 12, Line 9. Please add “after the wear test” in the sentence “Fig. 11 displays the three-dimensional topography…”

·         Page 12, Line 23. The abbreviation RT was not explained in the text of the manuscript.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The paper reports on fabrication and investigation of TiN/TiSiN multilayer coatings that posses rather high harness. The proper selection of thickness modulation type and layer combination allows optimizing mechanical properties. The paper conclusions of the paper are based on careful analysis of crystalline structure and phase composition followed by the investigation of mechanical properties. The paper is very well organized, the conclusions are very clearly justified. The only two comment are the following:

1) some phrases are to be checked in terms of sentence organization (see Comments on the Quality of English Language).

2) In the last sentence of the conclusion the authors state that "the maximum critical load values ... demonstrated the highest adhesive strength in G3 structure". In the conclusion it is better to specify the structure, not to refer to sample number.

The meaning of following sentences was not clear:

1. A combined with the HRTEM images, the lower angle lattice parameter of the coatings is 4.14 A compared to the literature value of 4.24 A for pure TiN.

2. Since the Si content in the coatings is 4 at.% and the maximum modulation period is only about 46 nm, TiSiN layer has a columnar microstructure, similar to growth mode to that of the TiN layer.

It is not clear to me how does the Si content and the thickness allow drawing the conclusion on a columnar structure.

Please check if there is no misprint in these sentences constructions. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Dear editor

The findings of this study are significant for both investigators and technologists involved in the design and production of hard coatings for cutting tools. The authors employed various experimental methods to investigate the structural properties of TiN/TiSiN multilayers with varying thicknesses of individual layers. This research aligns well with the focus of coatings. Overall, the quality of the presentation, discussion, and implications meets the standards required by this journal. Nevertheless, there are some concerns that the authors must address to prepare the manuscript adequately for publication. A comprehensive list of these issues is presented below.

with my best

Comments for author File: Comments.pdf

The manuscript needs to be refined in terms of its English language after undergoing correction.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Dear Editor,

I would like to express my recommendation to accept the paper in its current form as the authors have effectively addressed all of my concerns.

Best regards,