Microstructural, Mechanical and Oxidation Resistance of Nanolayer Sputter-Deposited CrAlN Hard Coatings

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript Coatings-2757329  entitled: „ Microstructural, Mechanical and Oxidation Resistance of Nanolayer Sputter Deposited CrAlN Hard Coatings”

The manuscript presents very valuable results. Also the presentation methods and graphics of the manuscript was well done. The presented researches are very actual and the presented subject fulfils the conditions for the publication in Coatings. Thus I strongly recommend the manuscript for the publication in the above mentioned journal. The strongest point of the presented work is the practical application of the studied system. The description and explanation of the obtained results is fully sufficient to publish in the Coatings. I have only some comments according to the presentation of the obtained results:

1.      Figures 2, 3 and 9 for example can be presented in some better way-the scale of the figures should in the range of the obtained results.

2.      The reference section should be checked carefully – lack of point at the end of the sentence. It should be the same in every point and it should fulfill the journal recommendations.

3.      The introduction section could be some more concise – especially that some information was in the previous papers of the Authors (but is only the proposition).

Author Response

see attached file

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In this manuscript, the author studied the microstructural, mechanical and oxidation resistance of nanolayer sputter deposited CrAlN hard coatings. The manuscript should be accepted after addressing the following issues;

1)      In Figure 1, the author mentioned the cathode at specific positions; did the position is also effect the morphology of the film

2)      In the material and methods section, the authors should provide information related to the source, purifications, etc.

3)       What is the effect of Al/Cr atomic ratios on the roughness of the films?

4)      The authors mentioned that “The SEM topography image of Cr-rich coatings shows a »cauliflower«-like topography, while the morphology of the Al-rich coating consists of “pyramid”-like grains……… but we cannot observe this morphology.

5)      In Figure 8, the authors measure the XRD diffraction patterns of (Cr,Al)N coatings, the authors should add JCPDs card number and also Rietveld refinement.

6)      In the manuscript, most of the abbreviations did not define before use

7)      Actually, to characterize the structures of composites, it is critical to reveal the interaction/interfaces of the components because compatibility holds the key to the performance of the materials. In this regard, further efforts should be devoted.

 

8)      Many spelling and formatting typos in this paper and the authors should check and revise them thoroughly.        

Comments on the Quality of English Language

Many spelling and formatting typos in this paper and the authors should check and revise them thoroughly.

Author Response

see attached file

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The microstructural, mechanical and oxidation resistance of nanolayered (Cr,Al)N nanolayer coatings with different Al/Cr atomic ratios were studied experimentally. The elemental composition phases were studied by EDS and XRD. The coating surface topography was analyzed by atomic force microscopy. It is reported that the oxide scale formed on the Al-rich double layered coating whereas the oxide scale of the Cr-rich coating mainly consists of the Cr2O3 layer. The oxidation tests showed that the Al-rich (Cr,Al)N nanolayer coatings exhibit a considerably better oxidation resistance than the Cr-rich ones. The topic is interesting and has important applications for the steel industry.

The abstract and introduction are fairly explained. Please introduce a paragraph in the introduction that emphasizes the novelty of the present work.

Please highlight the significance of the study.

Elaborate why this study is important because corrosion nature in the presence of Cr has been studied many times even with the altering the concentration/composition. What aspect makes this study unique to attract a larger audience?

Correct Table 3, Al/Cr is wrong. Same problem for Figure 9,10. Please check all the labels and axes of all Figures.

I have seen a comparative plot of temperature but in the abstract this aspect is not mentioned.

In Figure clear whether it is the lattice constant of the lattice parameter.

What is the difference between Figure 8 and 11? Can you combine and compare them?

Figure 12 is blur and doesn’t seem to contribute anything. Please explain this Figure and the purpose of adding two temperatures. Use high-quality Figures Pls.

Where are the mechanical properties? highlight which mechanical properties are measured. please divide the result section into mechanical, and microstructural parts clearly.  

I noticed that all results and discussion portion has a lot of Figures and most of the findings are not being compared with any literature. I would rather suggest comparing the values with published data.

 

 

Author Response

see attached file

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

accepted in the present form

Comments on the Quality of English Language

looks okay

Reviewer 3 Report

Comments and Suggestions for Authors

The quality of the manuscript has been improved and paper is in acceptable form