Enhanced Hot Salt-Water Corrosion Resistance of NiCoCrAlY-AlSiY Coating by Ion-Beam-Assisted Deposition

Round 1

Reviewer 1 Report

Detailed comments:

1. The English of the text should be checked
2. Please eliminate multiple references. After that, please check the manuscript thoroughly and eliminate ALL the lumps in the manuscript. This should be done by characterizing each reference individually and by mentioning 1 or 2 phrases per reference to show how it is different from the others and why it deserves mentioning. Multiple references are of no use for a reader and can substitute even a kind of plagiarism, as sometimes authors are using them without proper studies of all references used. In the case, each reference should be justified by it is used and at least short assessment provided. 
3. Line 61 - please correct Ti6Al4V with Ti₆Al₄V
4. Fined Line 95, and lines 96-110 it is necessary?
5. Lines 112-115, authors write: “For these two composite coatings, the diffraction peaks were primarily located in the outer layer, whereas those of silicon and yttrium were located lower in the AlSiY layer, and these strong diffraction peaks were assigned to the Al phases” – all peak were attributed to the Al phases. I have doubts about this statement, and it should be supported by values and data compared to the literature. Also, for Figure 1, at XRD what represent each peak, phase system, lattice parameters
6. Lines 116-117, “The XRD results clearly indicate that the chemical composition of the samples were uniform and no other impurities.” – where are indicated the chemical composition. Why are not difference between the samples? More information can be indicated.
7. For Figure 2 and Figure 3, Figure 5, the comparison between the obtained results and other from literature must be done.
8. At equations (4) and (5) what represent 1-2? Also, correct the equation (7), put 2 at HClO, or delete 2 from HCl and put ½ at O₂
9. Comparison between the obtained results and measured in this study with other reported studies should be done and included for more clarity (indicate values not just number of reference).
10. More Conclusions with the best results obtained, indicate the values

 

Author Response

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Reviewer 2 Report

All the comments are listed in the paper.

Can you examine the corrosion properties of the NiCoCrAlY-AlSiY coating by some other technique (potentiodynamic polarization, EIS, etc.).

Comments for author File: Comments.pdf

Author Response

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Reviewer 3 Report

The work is interesting and has great cognitive and application potential. The purposefulness of the research was correctly justified by the authors. Most of the research results are unambiguous and confirm the correctness of the inference. However, there are research threads in the article that need to be completed.

Detailed comments:

1. How was the selection of process parameters (Table 1), whether the values of these parameters are the result of literature studies or experimental optimization. If it is the effect of experimental optimization, what factors determined the choice of these parameters?
2. In line 95 there is a duplicate of the heading from line 65 and the text from the journal's guidelines. The text from lines 95-110 should be removed from the article.
3. Lines 83 and 84: "In order to plot the corrosion kinetic curves, all samples were weighed at regular intervals" - please specify the intervals at which measurements were made
4. Accurate measurement of the sample mass during corrosion testing is the basis for the preparation of reliable corrosion kinetics curves and the correct evaluation of the process.Due to the relatively small weight losses / gains occurring during the corrosion test, the method of sample preparation for measurement and the measurement error itself are of key importance. The authors write in line 85: "Before weighing, the sample was rinsed more than three times in boiling deionized water" - this text shows that individual samples were rinsed with varying degrees of intensity.How it was concluded that the rinsing process should be completed.What evaluation criteria have been adopted? What was the error of mass measurement?
5. The scope of individual studies should be quantified and the specific objectives of each studies should be discussed more precisely.
6. Line 83: "The heating rate in this experiment was less than 10 ° C -min" - the information should be detailed or the range of the heating rate used in the experiment should be specified
7. The analysis of the differences in masses of samples E1 and E2 obtained at different stages of the corrosion test is superficial and comes down only to presenting the mass gains without interpreting the phenomena and partial processes responsible for the course of the corrosion kinetics curves. The diagram shown in Fig. 8 is valuable, but is too general in nature, therefore it does not explain all the changes in the masses of the samples shown in Fig. 3.
8. To mark the phases on the diffraction patterns 4a and 4b, the authors used very similar markers. The differences in their shape are visible only after enlarging the drawings. It is suggested to use markers clearly different in shape or to introduce different colors of these markers.
9. The differences in the microstructures of samples E1 and E2 shown in Figure 5 are unambiguous and convincing. It is worth noting, however, that microstructural effects, and especially adhesion effects, sometimes depend on the preparation of the metallographic samples. The authors did not present the procedure of sample preparation for microscopic examination. This should be completed.
10. What were the dimensions of the samples?

Author Response

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Round 2

Reviewer 1 Report

The manuscript has been improved and can be accepted for publication.

Author Response

We sincerely thank the reviewer for his constructive suggestions on our paper

Reviewer 2 Report

If the corrosion properties, corrosion resistance of this coating, will be carried out in subsequent characterization, then the title, abstract, and conclusions must be revised according to the results shown. 

Author Response

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Reviewer 3 Report

The work is interesting and has cognitive and application value. In the revised version of the article, however, there was an error in the marking of the titanium alloy. The current marking indicates that one of the most common titanium alloys, i.e. Grade 5, is a chemical compound !!

Ti-6Al-4V alloy is the most widely used alpha-plus-beta titanium alloy and is also the most common of all titanium alloys. The correct marking is Ti6Al4V or Ti-6Al-4V. Titanium alloy is incorrectly marked on lines 68, 73, 156 and 203. Correction is necessary. 

 

Author Response

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