Estimation of MoS2 Coating Performance on Bronze and Steel in Vacuum at High Temperatures
, Margarita S. Kukushkina 2, Dobrynya V. Kolodko 2,3 and Tatiana V. Stepanova 2Round 1
Reviewer 1 Report
The topic of this work called “Estimation of MoS2 Coating Performance on Bronze and Steel in Vacuum at High Temperatures” is actually in nowadays. The authors presented extensive experimental material. The results shown in the paper are of an application nature. However, the topic contains errors. My comments are as follow:
Major comments:
The main results of the work are missing from the abstract.
Samples A1 and A2 are the same (according to Table 2), but the results shown in Fig. 8 are different. This requires some explanation.
The critical loads Lc1, Lc2, Lc3 should be determined as in the applicable standard for scratch test. This makes it possible to compare the results with the literature. It is not appropriate to enter new definitions for critical loads.
It's unclear for what purpose the friction coefficient was determined in the initial run-in time of the 2000 s.
It's unclear, why for samples B2 and B3, the friction coefficients are different (at 2000 s) in Fig. 3 and Fig. 5b, Fig. 6 respectively.
The matching of patterns to the XRD results for MoS2 should be reviewed. The first peak in a hexagonal crystal is for plane (002), not (003) as the authors wrote. It is worth explaining whether the directions of MoS2 crystals growth change depending on the deposition parameters.
The authors write: "Sandblasting hardens the surface layer and aligns its structure in a certain way, which is favorable for the growth of crystals of the molybdenum disulfide coating. The sentence: "aligns its structure in a certain way, " is incomprehensible.
Minor comments:
In the description of Fig. 1, it should be added that it concerns the MoS2 coating deposited on bronze.
Fig. 2 shows the coatings on the steel, not the coatings on bronze as shown in the caption.
Redundantly, in Table 4, the content of Table 2 was repeated and new signs of bronze samples were introduced.
In Table 5, bronze signs should be the same as Table 2.
Worth explain what f means in Table 7.
Fig. 10 is unreadable for acoustic emission signals.
Fig.14, the description of the phases in the upper right corner is hardly readable.
Fig. 15, the description of the planes is not readable.
Comments for author File: 
Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 2 Report
This paper reported the effect of the deposition mode parameters on mechanical and structural properties of coatings. The author designed a large number of experiments and obtained reasonable results. This study provides a method for estimation of MoS2 coating performance in vacuum at high temperatures. Therefore, I think it can be published. To improve the quality of this paper, some correct suggestions are as follow:
1、Why not sputter Ti as butter layer first in the sputtering process. After the scratch test, I saw obvious film peeling off. I think the existence of Ti butter layer will enhance the adhesion strength between the MoS2 films and substract.
2、After the scratch test, cracking and peeling of the film occurred. Has the author observed the effect of film cracking on the substrate at this time? Because recent studies have shown that cleavage cracking of ductile-metal substrates induced by brittle coating fracture. Such as: Acta Materialia 217, 117179 and Acta Materialia 152, 77-85. I think the author should quote the above literatures.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The work was completed and corrected. It is a valuable material. I recommend further consideration of this work for publication in Coatings.
