Aluminum Co-Deposition via DC Magnetron Sputtering for Enhanced Pitting Resistance of Copper–Nickel Alloys

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

There are no comments on the article. It can be published as is.

Author Response

Thank you for 

Reviewer 2 Report

Comments and Suggestions for Authors

There is no explanation given for applying EIS in addressing the corrosion stability assessment. No in situ investigations of corrosion kinetics at OCP were mentioned specifically. How the passivity is affected by lower pH values (Aauthors can also refrence Pourbaix diagrams if they find it necessary) 

Comments on the Quality of English Language

Some typos and minor edits may be required before finalizing documents.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this paper, Cu–Ni and Cu–Ni–Al alloy thin films were deposited using a direct-current (DC) magnetron sputtering system. The changes in the thin film upon Al addition to the alloy was examined through material analysis. Further, the corrosion resistance was evaluated via cyclic corrosion and electrochemical tests. Although the research content has certain practical value, there are still some doubts that have not been well explained. Thus, this paper should be major revised according to the following comments:

1.The first part of the paper is not titled.

2.The sputtering equipment used for deposition needs to place the physical map for reference.

3.On the two figures A and B in Figure 2, it is described that the crystal size of B is similar to that of Cu-Ni alloy, but the picture shows that the crystal size of B is larger than that of Cu-Ni alloy.

4.The lower part of the image after the CCT cycle of Cu70-Ni15-Al15 in Fig.4 shows a fuzzy structure, which is not described and analyzed.

5.The grammatical errors and format problems in the paper should be carefully
checked and modified.

6.In the following paper, The preparation of Al2O3 / Al6Ti2O13 composite ceramics by directional energy deposition was studied,which may be helpful in the introduction of the paper:Huang Y F, Wu D J, Zhao D K, Niu F Y, Ma G Y. 2021. Investigation of melt-growth alumina/aluminum titanate composite ceramics prepared by directed energy deposition. Int. J. Extrem. Manuf. 3, 035101.

Comments for author File: Comments.pdf

Comments on the Quality of English Language can be improved

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Comments to the Author

The manuscript presents a promising study on the fabrication and characterization of CuNi Co deposition of Al alloys using DC magnetron sputtering. The work is well-written and organized, with clear objectives and methodologies. The results are presented in a comprehensive manner with appropriate figures and tables. However, there are a few areas that require further clarification or improvement.

1) Line number 32-33: “These alloys were previously developed for military purposes and are now widely applied in various fields, such as heat exchangers, seawater piping in ships, and offshore plants.” Heat exchangers and seawater piping applications will create hydrogen pressure inside a pipe during water flow. It will favor the formation of aluminium hydride (AlH₃). Hydride formation can lead to hydrogen embrittlement, where the material becomes brittle and susceptible to cracking. How to control this effect?

2) Cu–Ni–Al thin films were deposited targets on stainless-steel (STS) plates via DC magnetron sputtering. Also, mention the deposited film thickness and find the oxidation percentage between increasing/decreasing the film thickness.

3) Figure 2 and 5 FESEM images contain features of microstructure images.. Kindly check and confirm

4) The manuscript could be further strengthened by incorporating additional characterization techniques, such as X-ray photoelectron Spectroscopy (XPS) and Surface roughness measurement. Based on your application (heat exchangers, seawater), higher surface roughness creates higher friction and reduces the energy level (output). Also, mention the depth profile value of your sample.

5)   What is the effect of atomic radii mismatches in metal coating? Whether to increase or decrease the mechanical properties? Like Al (0.143 nm), Cu (0.128 nm), and Ni (0.124 nm).

6) What is the degradation rate of the alloy coating considered in this research?

7) Citing bulk references in the introduction section is to be avoided (for ex. [1 - 4], [5 - 7], [11 - 14] etc.. Not more than two references can be combined and cited. Need to check and correct throughout the manuscript.  

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 4 Report

Comments and Suggestions for Authors

Authors have addressed the queries raised by the reviewers satisfactorily .

Therefore the revised manuscript can be considered for further processing