Review Reports - Study on the Corrosion Resistance of Supersonic Plasma Spraying Al2O3 Thin Layer and SiO2 Sealer Alternately Deposited Coating

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors

I congratulate you on the paper you have done. I believe that the paper is very interesting, but in order to be published in the Coatings journal, it should be completed with the following:

1) Certain passages in the introduction (rows 27-31; 45-50; 93-97; 118-120...) as well as others in the paper aren't clearly explained. Please paraphrase.

2) The paper contains too many unexplained terms. Some of them have the same meaning: "traditional sealed coating" and "conventional sealing coating". Please check and correct.

3) Try to explain more clearly where and when you use the YRS and how you have applied it.

4) The explanations in the rows 118-126 aren't clear (including the figure). Please rephrase and explain clearly the figure. If it is necessary, try to insert a second figure or use a diagram.

5) Paragraph 2.2 isn't clear. Please try to introduce an experimental program that includes: how many types of layers you had, how they were obtained, how many samples you used, etc. ... and use specialized terms.

6) Please check the data in Table 1... somewhere there is an error: the spraying distance is 100 mm and the plasma temperature is 10000K???? (isn't the distance too small???)

7) The titles of paragraphs 2.5 and 3.4 begin with capital letters.

8) Figure 3 shows only the XRD profiles of the deposits you are treating (those in Figure 5)

9) Please check that the paper contains technical terms well explained in short sentences.

Author Response

Dear reviewer，

We feel great thanks for your professional review work on our article. As you are concerned, there are several problems that need to be addressed. According to your nice suggestions, we have made extensive corrections to our previous draft, the detailed corrections are listed below.

Reviewer·1#

Certain passages in the introduction (rows 27-31; 45-50; 93-97; 118-120) as well as others in the paper aren't clearly explained. Please paraphrase.

The author's answer:Thanks for your suggestion. We have made the following modifications to the content you mentioned.

For rows 27-31：We have supplemented the introduction of thermal spraying technology.
For rows 45-50：We have reinterpreted the content of this section.
For rows 93-97：We have provided some explanations for alternating sedimentation.
For rows 118-120：We were really sorry for our careless mistakes. Thank you for your reminder.

Reviewer·2#

The paper contains too many unexplained terms. Some of them have the same meaning: "traditional sealed coating" and "conventional sealing coating". Please check and correct.

The author's answer:We think this is an excellent suggestion.We have replaced all "conventional sealing coating" in the manuscript with "traditional sealed coating" based on the reviewer's suggestions.

Reviewer·3#

Try to explain more clearly where and when you use the YRS and how you have applied it.

The author's answer:As suggested by the reviewer, We have partially rewritten section 2.2, including the application of YRS.

Reviewer·4#

The explanations in the rows 118-126 aren't clear (including the figure). Please rephrase and explain clearly the figure. If it is necessary, try to insert a second figure or use a diagram.

The author's answer:We think this is an excellent suggestion. We have reinterpreted the diagram.

Reviewer·5#

Paragraph 2.2 isn't clear. Please try to introduce an experimental program that includes: how many types of layers you had, how they were obtained, how many samples you used, etc. ... and use specialized terms.

The author's answer:We have re-written this part according to the Reviewer’s suggestion.

Reviewer·6#

Please check the data in Table 1... somewhere there is an error: the spraying distance is 100 mm and the plasma temperature is 10000K???? (isn't the distance too small???)

The author's answer:Thank you to the reviewer for raising questions about the data in Table 1, so we will explain the data itself.

The temperature of plasma flame flow is a decreasing process, the central temperature of the flame stream can reach 10000K, but as the distance increases, the flame flow temperature of 100mm is approximately 4000K, which happens to be the complete melting of alumina particles.
During the spraying process, the plasma flame flow follows the rapid movement of the robotic arm and does not generate significant heat accumulation.

Therefore, the data in Table 1 is accurate.

Reviewer·7#

The titles of paragraphs 2.5 and 3.4 begin with capital letters.

The author's answer:Thanks for your careful checks. We are sorry for our carelessness. We have made modifications to the titles of paragraphs 2.5 and 3.4 begin.

Reviewer·8#

Figure 3 shows only the XRD profiles of the deposits you are treating (those in Figure 5)

The author's answer:We think this is an excellent suggestion.We have made modifications to Figure 3 and can clearly see the XRD curves of the sediment and the original powder.

Reviewer·9#

Please check that the paper contains technical terms well explained in short sentences.

The author's answer:Thanks for your suggestion. We have made every effort to adjust technical terms that can be explained clearly through short sentences

We tried our best to improve the manuscript which will not influence the content and framework of the paper. We appreciate for Editors/Reviewers’ warm work earnestly, and hope the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Manuscript ID coatings-2781889

Despite the efforts done by the authors, and the manuscript contains a good story, there are some important points that should be considered by the authors.

1. In abstract: "Scanning electron microscope (SEM), X-ray diffraction instrument (XRD)". This sentence does not have any meaning. Please, check.

2. The manuscript should be revised grammatically, and the language should be improved.

3. Keywords must have words that express the purpose of the research. Please add more words.

4. In introduction: " ….on the surface of large work parts or parts can meet the insulation, heat insulation, wear resistance and corrosion resistance,…". What is the difference between insulation and heat insulation?

5. Does the authors studied the influence of XRD and SEM on the coated layer !!!! Please, check the last paragraph in the introduction again and correct this language mistake.

6. In the introduction: The authors talked about thermal shock resistance without citing any related reference. May the following reference treated this property for Alumina ceramic "Thermal Shock Behaviour of Alumina/Iron Composites” Journal of Materials Science & Technology, 18 [4] (2002) 347-350".

7. In experimental section: the authors mentioned that the thickness of the L.C.St is 50155 mm. Is this thickness correct?

8. Lines 105-106 (experimental section). The particle size of the powder was 15-45 μm. Which powder?

9. The authors used μm and microns in the manuscript in different sentences. Please use one form in writing.

10. Please check the following sentence again "The X-ray diffraction instrument (XRD, Bruker D8 Advance, Bruker, Germany) with Cu target K α-ray was used in the scanning range of 10-90". What do you mean by 10-90?

11. "2.5. corrosion test" should be corrected to "2.5. Corrosion test "

12. Please correct Al2O3 to Al₂O_3.

13. For all Figures 6-11 (x-axis and y- axis), please leave a space between the writing and the unit of measurement.

14. In conclusion, please clarify the main finding of your experimental study.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The manuscript should be revised grammatically, and the language should be improved.

Author Response

Dear reviewer，

Reviewer·1#

In abstract: "Scanning electron microscope (SEM), X-ray diffraction instrument (XRD)". This sentence does not have any meaning. Please, check.

The author's answer:We sincerely thank the reviewer for careful reading. As suggested by the reviewer, we have corrected the “Scanning electron microscope (SEM), X-ray diffraction instrument (XRD)” into “SEM, XRD”.

Reviewer·2#

The manuscript should be revised grammatically, and the language should be improved.

The author's answer:Thanks for your suggestion. We have tried our best to polish the language in the revised manuscript.

Reviewer·3#

Keywords must have words that express the purpose of the research. Please add more words.

The author's answer:We think this is an excellent suggestion.We have supplemented the keywords.

Reviewer·4#

In introduction: " ….on the surface of large work parts or parts can meet the insulation, heat insulation, wear resistance and corrosion resistance,…". What is the difference between insulation and heat insulation?

The author's answer:We sincerely thank the reviewer for careful reading."Insulation and heat insulation" respectively represent electrical insulation and thermal insulation, to avoid unnecessary disputes, we have decided to retain only “insulation”.

Reviewer·5#

Does the authors studied the influence of XRD and SEM on the coated layer !!!! Please, check the last paragraph in the introduction again and correct this language mistake.

The author's answer:We think this is an excellent suggestion.We have made revisions to the last paragraph of the introduction in the manuscript based on the reviewer's suggestions, and explained the significance of XRD and SEM in it.

Reviewer·6#

In the introduction: The authors talked about thermal shock resistance without citing any related reference. May the following reference treated this property for Alumina ceramic "Thermal Shock Behaviour of Alumina/Iron Composites” Journal of Materials Science & Technology, 18 [4] (2002) 347-350".

The author's answer:We sincerely appreciate the valuable comments. We have checked the literature carefully and We have decided to investigate "Thermal Shock Behaviour of Alumina/Iron Composites” Journal of Materials Science & Technology, 18 [4] (2002) 347-350" add to manuscript.

Reviewer·7#

In experimental section: the authors mentioned that the thickness of the L.C.St is 50155 mm. Is this thickness correct?

The author's answer:Thanks for your careful checks. We are sorry for our carelessness.We will correct 50155 mm to 50×15×5mm.

Reviewer·8#

Lines 105-106 (experimental section). The particle size of the powder was 15-45 μm. Which powder?

The author's answer:Thanks for your careful checks. We are sorry for our carelessness. We will correct“the particle size of the powder was 15-45 μm” to “the particle size of the binder layer powder NiCr and the top layer powder Al₂O₃ were both 15-45 μm”.

Reviewer·9#

The authors used μm and microns in the manuscript in different sentences. Please use one form in writing.

The author's answer:Thanks for your careful checks. We are sorry for our carelessness.We will unify the two in the manuscript as μm.

Reviewer·10#

Please check the following sentence again "The X-ray diffraction instrument (XRD, Bruker D8 Advance, Bruker, Germany) with Cu target K α-ray was used in the scanning range of 10-90". What do you mean by 10-90?

The author's answer:Thanks for your careful checks. We are sorry for our carelessness.We have changed 10-90 to 10°-90°.

Reviewer·11#

"2.5. corrosion test" should be corrected to "2.5. Corrosion test "

The author's answer:Thanks for your careful checks. We are sorry for our carelessness.We have corrected "2.5. corrosion test" to "2.5. Corrosion test ".

Reviewer·12#

Please correct Al2O3 to Al₂O₃.

The author's answer:Thanks for your careful checks. We are sorry for our carelessness.We have made revisions to all the Al2O3 in the manuscript.

Reviewer·13#

For all Figures 6-11 (x-axis and y- axis), please leave a space between the writing and the unit of measurement.

The author's answer: Thanks for your suggestion. We have made adjustments to the 6-11 diagram.

Reviewer·14#

In conclusion, please clarify the main finding of your experimental study.

The author's answer:We think this is an excellent suggestion. We have made changes and additions to the conclusions section.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Ref_comments to the paper titled as “ Study on the corrosion resistance of supersonic plasma spraying Al₂O₃ thin layer and SiO₂ sealer alternately deposited coating” written by the authors: Yu-xi, Feng , Ming Liu, Lie Jiaa, Yu Bai, Guo-zheng Ma, Xin-yuan Zhou, Hai-dou Wang and Hao-zhen Wang.

Work on optimizing the properties of a number of the coatings, including ceramic ones, has been carried out very intensively in the last 10 years due to changes in the environmental situation and a significant increase in the influence of an aggressive environment on the materials. The corrosion problem and the question to eliminate the corrosion effect is very important. From this point of view the current article is actual and modern.

For the first, the authors have made the literature search connected with the analysis of 32 references. Good, but it is not enough for this perspective area of the study. Please include 3-5 papers written namely last 3 years. The manuscripts published last years can extend this topic good understanding and its useful for the human life and industry.

The paper has good illustrations and equipment to study: SEM-images, the process to prepare the coatings structures, XRD profiles, microtopography images with good resolutions, microhardness diagrams, equivalent set-up, etc. have been shown. The instrumentations are very nice as well!

Some questions and recommendations:

1). About Figure 6. Three coatings microhardness diagram: (a) average microhardness; (b) depth away from the coating surface. Please show the roughness of the optimized and alternatively used coatings in your study.

2). About Figure 12. The variation of electrochemical corrosion parameters of alternately sealed coating and traditional sealed coating: (a) Rp… Please explain what will be happen after the month for your coatings? Have you observed the saturation after 500 hours? It seems to me that the time less than the month is not enough to make the good conclusion about the affective treatment results via your approach.

3). Conclusion should be extended. Please include all your basic results and clear explain the observed tendency established via your method application.

As for my local opinion, this paper can be published after the minor corrections. Please answer the questions mentioned above.

Comments for author File: Comments.pdf

Author Response

Dear reviewer，

Reviewer·1#

About Figure 6. Three coatings microhardness diagram: (a) average microhardness; (b) depth away from the coating surface. Please show the roughness of the optimized and alternatively used coatings in your study.

The author's answer:Thank you for pointing this out. But as mentioned in section 2.5 of the manuscript, we had already uniformly ground and polished all the samples before conducting the experiment, so the roughness experiment was not included in our plan.

Reviewer·2#

About Figure 12. The variation of electrochemical corrosion parameters of alternately sealed coating and traditional sealed coating: (a) Rp… Please explain what will be happen after the month for your coatings? Have you observed the saturation after 500 hours? It seems to me that the time less than the month is not enough to make the good conclusion about the affective treatment results via your approach.

The author's answer:Thank you very much for pointing out this important issue. We agree with your opinion.Unfortunately, due to the limited time and funding, we did not supplement experimental validation.The aim of this study is to investigate the corrosion resistance of sealed alumina coatings. Therefore, 20 days of EIS and 60 days of immersion corrosion can to some extent explain this conclusion.We have added this deficiency to the restriction section and will collect one month's EIS data for further research in the future.

Reviewer·3#

Conclusion should be extended. Please include all your basic results and clear explain the observed tendency established via your method application.

The author's answer:We think this is an excellent suggestion. We have made changes and additions to the conclusions section.