PVD Black Coating for Decorative Applications

Round 1

Reviewer 1 Report

-Comments regarding the sustainability, stability and durability of the coating should be included

- Fig. 1 XRD: Was the background subtracted, or why is the signal for the substrate almost not visible at low angles? Anchor lines should be used to index the reflexes to a certain compound. The signal line is too thick. Why not using cps instead in a.u.?

- table 2 (and other tables, too): check line breaks for better reading and capitalization of letters should be uniform

- equations should be written in the same font size

- a description of the utilized raw materials, including the substrate, is missing. To my opinion, a characterization of the substrate needs to be included for reproducibility

-abbreviations need to be explained before their first usage, e.g. EDX, AFM and so on.

- Fig.1 stoichiometric indices must be subscripted, figure should be revised regarding the legend: Put explanation of material inside the figure and the marking of reflexes in the legend

Fig. 2 needs to be revised regarding the axis labeling

- to my opinion, the standard of the Figures should be improved, they do not meet the standard for scientfic publication

-Fig. 6 Legend of SEM figure, especially the scale bar is almost not readable

- why is Fig. 8 cut in this irritating way?

I detected only minor errors in spelling.

Author Response

see word file

Author Response File: Author Response.pdf

Reviewer 2 Report

The article requires improvement in terms of describing the deposition process and characterizing coatings.
1. typo: table 1 does not indicate the units of measurement of total pressure (Pa?)
2. It is necessary to provide a more recent link (link 21 is an article from 2003). Or give more details of the deposition: type of discharge (DC, pulse DC, etc.). On line 74 give the details of plasma etching, and on line 77 - the timing parameters of the pulses.
3. Authors should check reference 22. The reviewer did not find any description of the details of diffuse reflectance measurement in this article.
4. line 86 typo (?) - maybe a spectrophotometer and not a photospectrometer
5. line 91 typo - scanning electron microscopy but not secondary
6. line 105 Regarding sample 48. A film thickness of 0.45 microns is quite sufficient for EDX analysis. Another thing is that for some beam energy it is impossible to use the semi-infinite layer model. In any case, the authors should indicate the beam energy when analyzing the EDX and provide arguments that neither the substrate nor the chromium layer contributes to the EDX spectrum.
7. The authors should think again about whether it is worth citing XPS data in the article. Whether or not there is a correlation between XPS and EDS data does not carry any information. If the authors had carried out XPS profiling, then the data on changes in the composition of the coating with depth could have been used, for example, to justify the use of a simple optical model (equation 2).

The description of the results also requires revision.
1. Figure 3b - indicate which curves belong to n and which to k.
2. Figure 3a - the spectrum of sample C46 is interesting. For the sake of discussion, the authors should give n and k at which the specular reflection is close to zero. And here is the remark on line 162 - equation 2 (Fresnel’s formula) describes only mirror reflection.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This paper studies PVD black coating, which has potential decorative application value in engineering. In order to meet the requirements of high-quality publication of the Journal, it is recommended to consider the following suggestions.

1. Except for "a coating thickness variation between 1 and 15 um" in Line 15, more quantitative data should be available in the Abstract.

2. "Within the frame of this work, we pretend to develop a coating, which can be deposited in PVD batch coating machines, consisting in layers, whose thickness variations and small variation of the vacuum conditions are not influencing the optical appearance." Is the second paragraph too short and does the logic need to be adjusted?

3. In the sentence of "The optical properties of the decorative layer are the complex refractive index ñc = nc + j kc", j means what?

4. It is best to have a summary of the current research status with a Figure or Table in the Introduction section. 

5. What is the basis for selecting parameter values in Table 1?

6. Section 2.3 of “Simulation of optical properties” should be expanded in details.

7. "Figure 2. a) Deconvoluted oxygen peak for samples C-48, C-43 and C-46 as determined by XPS." and "Figure 2. b) Deconvoluted carbon peak for samples C-48, C-43 and C-46 as determined by XPS." may be not meet the standard of Coatings.

8. The similar problem should be addressed in Figure 3.

9. The discussion section suggests a side-by-side comparison with other literature.

10. It is not recommended to put references in the conclusion section.

 

Author Response

see word file

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Revised version can now be accepted for publication.

Only very few corrections in spelling needed.

Author Response

The paper was read by a native english speaker and some corrections to the english usage was done. I thank you for your previous comments.

Reviewer 2 Report

The authors have made the necessary corrections and additions. However, the authors should clarify (or correct) what they wrote in lines 111-114. The use of silicon as a substrate does not in any way eliminate the influence of the substrate when determining the composition of the coating. The main thing is that chromium from the 200 nm pre-layer should not contribute to the EDX spectrum. (From lines 86-87 it follows that there is also a 200 nm layer of chromium on the silicon). This is usually achieved by choosing the beam energy. And the use of a silicon substrate can of course help in this choice, but provided that only a coating is applied to silicon without a pre-layer of pure chromium. This remark, of course, does not significantly affect the overall impression of the paper.

Author Response

The paper was read and corrected by a native english speaking colleague and some changes to the english language usage were done. Please find attached the comment on the EDX measurements. I thank you for your comments Best Regards

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors have addressed all my concerns.

Author Response

The paper was read by a native english speaking colleague and some changes to the usage of the english language were done. I thank you for your previous comments. Best Regards