Review Reports - Aluminide Thermal Barrier Coating for High Temperature Performance of MAR 247 Nickel Based Superalloy

Round 1

Reviewer 1 Report

The article is very interesting, written in a good language and talks about a promising study concerning the improvement of the physical and mechanical properties of nickel alloys at high temperatures using coatings. However, there are several questions. Further in () is the line number in the article.

1. (103) Important images (Figure 2), however, they are far from the best quality, unlike those that were, for example, in the article: "Thermal Barrier Stability 283 and Wear Behavior of CVD Deposited Aluminide Coatings for MAR 247 Nickel Superalloy" (Figure 1). Is there any way to replace them with similar ones, but shot with a higher resolution?

2. (109) I think the scattering in coating thickness should be indicated.

3. (137) The use of the coating can significantly improve the strength properties of the nickel alloy. But what about plastic properties (elongation) at least at room temperature, the measurement of these properties should not be difficult and will be interesting to readers.

4. (156) Some of the most important graphs (Figure 4) that show the benefits of using coatings at high temperatures. However, why was it impossible to approximate the obtained data with straight lines in double logarithmic coordinates and use the Coffin-Manson or Basquin equation? Then, having received the appropriate coefficients, it would be possible to quantify the differences in coated and uncoated materials.

5. (187) It is not clear on the graphs which curve, to which test to refer. Perhaps, for some results using the dashed line should help to distinguish them.

Author Response

Detailed Response to Reviewer Comments

Ms. Ref. No.: coatings-1026443

Title: Aluminide thermal barrier coating for high temperature performance of MAR 247 nickel superalloy

Coatings Dear Sir or Madame,

I would like to thank you very much for your letter and the reviewer’s comments on our manuscript (No.: coatings-1026443). We appreciate your very valuable comments, that gave us a chance for revising the manuscript.

We have addressed all of the comments and revised the manuscript accordingly. All of the changes have been highlighted in yellow in the revised manuscript. Detailed responses to the comments are described in the “Response to Reviewers” point by point.

We now resubmit the manuscript for your further consideration for publication in your journal. We sincerely hope this revised manuscript will be finally acceptable for publication. If you have any questions about this manuscript, please do not hesitate to contact me.

Best regards

Mateusz Kopec

On behalf of all co-authors

Institute of Fundamental Technological Research

Polish Academy of Sciences

E-mail: mkopec@ippt.pan.pl

Reviewer’s Comments:

Reviewer #1:

Response: We would like to thank the reviewer for the comment. The article was significantly improved according to all reviewers comments and changes were highlighted.

Response: We would like to thank the reviewer for the comment. New photographs for Fig.2 were provided.

2. (109) I think the scattering in coating thickness should be indicated.

Response: We would like to thank the reviewer for the comment. Corrections were added and highlighted in the article (133).

Response: We would like to thank the reviewer for the comment. Corrections were added and highlighted in the article (Table 3). Additional discussion was added (152-173).

Response: We would like to thank the reviewer for the comment. Authors highly appreciate this comment. The coefficients were determined by authors according reviewer suggestions however it was decided to include such analysis in next paper in which effect of coating on fatigue response will be studied in details. M and B parameters were calculated according equations presented below :

and

Room temperature
Without coating		NiAl coating
m-parameter	B-parameter	m-parameter	B-parameter
5,567718281	3,37226E+20	10,61646333	2,93517E+34
7,565230908	1,19485E+26	2,529264428	1,0004E+12
4,24248549	9,37098E+16	7,567390013	3,96207E+25
6,431523218	7,58459E+22	9,561411093	6,11623E+30
1,582800744	10357171772
12,16309056	3,5139E+37

900°C
m-parameter	B-parameter	m-parameter	B-parameter
3,825509595	2,29946E+13	20,56716601	1,06823E+60
4,496556106	1,00875E+15	6,349992748	4,5388E+21
30,95527668	9,57475E+77	7,457179446	4,22256E+24
80,05649889	1,6642E+194	1,349271308	1,22303E-09
22,85330182	1,7024E+59	12,71840407	1,75415E+38
		7,49408847	4,4677E+24

5. (187) It is not clear on the graphs which curve, to which test to refer. Perhaps, for some results using the dashed line should help to distinguish them.

Response: We would like to thank the reviewer for the comment. Figure 7a was corrected and replaced.

Author Response File: Author Response.docx

Reviewer 2 Report

I do not see any significant contribution to the field of coating technology. The paper lacks scientific analysis and discussion. It looks like reporting data without any comprehensive discussion.

Author Response

Detailed Response to Reviewer Comments

Ms. Ref. No.: coatings-1026443

Title: Aluminide thermal barrier coating for high temperature performance of MAR 247 nickel superalloy

Coatings Dear Sir or Madame,

Best regards

Mateusz Kopec

On behalf of all co-authors

Institute of Fundamental Technological Research

Polish Academy of Sciences

E-mail: mkopec@ippt.pan.pl

Reviewer’s Comments:

Reviewer #1:

I do not see any significant contribution to the field of coating technology. The paper lacks scientific analysis and discussion. It looks like reporting data without any comprehensive discussion.

Response: We would like to thank the reviewer for the comment. The article was significantly improved according to all reviewers comments and changes were highlighted accordingly. The introduction section was extended and additional literature was discussed. All results obtained were discussed and compared with literature available in the field. We hope that the corrections provided would allow to reconsider our paper for possible publication in Coatings.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Authors

Th topic of the manuscript falls within the journal interest. However i hardly found any previous wok and research in this area. There is hardly any comparison of this work with previous researchers. Although CVD is one of the standard technique, widely applicable by researcher for coating purposes. What's new in this work? Is this approach is very new and novel? I find this gap strongly in introduction and write up.

Secondly although author claim there is no detachment of coating from the material. However there is a crack very prominently observed from interlayer to coating. How author justify this? Also regarding creep , the presentation of the result is very poor. With issue with morphology, there are some phases within matrix, authors hardly describe this. So in my point of view a lot of lacking points are observed. So authors need to work significantly on the article to improve the quality of the manuscript.

Author Response

Detailed Response to Reviewer Comments

Ms. Ref. No.: coatings-1026443

Title: Aluminide thermal barrier coating for high temperature performance of MAR 247 nickel superalloy

Coatings Dear Sir or Madame,

Best regards

Mateusz Kopec

On behalf of all co-authors

Institute of Fundamental Technological Research

Polish Academy of Sciences

E-mail: mkopec@ippt.pan.pl

Reviewer’s Comments:

Reviewer #1:

Th topic of the manuscript falls within the journal interest. However i hardly found any previous wok and research in this area. 1.There is hardly any comparison of this work with previous researchers. Although CVD is one of the standard technique, widely applicable by researcher for coating purposes. What's new in this work? Is this approach is very new and novel? I find this gap strongly in introduction and write up.

Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

The article has been improved and its should undergo some minor revision before considering for publication. Such as

1. Fig. 2 is reductant. This experimental set up is very unnecessary.

2. Fig. 6 , authors need to more clarify in presentation, its very unclear about edge and center part.

3. Author need to include some more reference about interfacial adhesion of NiTi alloy with other materials such as

as below

Study of Interfacial Adhesion between Nickel-Titanium Shape Memory Alloy and a Polymer Matrix by Laser Surface Pattern, 2020/1, Applied Sciences, Volume 10, Issue 6, Pages 2172.

Author Response

Dear Reviewer,

On the behalf of all authors, I would like to thank you for your valuable comments.

Please find our response below:

The article has been improved and its should undergo some minor revision before considering for publication.

1. Fig. 2 is reductant. This experimental set up is very unnecessary.

Figure 2 with experimental setup was delated.

2. Fig. 6 , authors need to more clarify in presentation, its very unclear about edge and center part.

Author changed the desciription and did not use words "edge" and central part.

Detailed text could be found below and was highlighted in the manuscript.

The scanning microscope observations of fracture areas of specimens subjected to cyclic loading at room temperature showed that the crack propagation in the layer was not transferred into the nickel matrix. The view of fracture area confirm the permanence of the interfacial adhesion as no cracks between the layer and nickel substrate were observed (Figure 6a). Such behavior can be a sign of good efficiency of CVD process applied. It should be emphasized additionally, that a satisfied layer coherence was attained (Figure 6b). Despite the multiple cracks, the layer remained adhered to the nickel based substrate. Numerous cracks in the aluminide layer were observed near the decohered area (Figure 6c). However, cracks in the layer itself do not limit the possibility of cyclic load carrying. Despite the multiple cracks found on the edge of the sample (Figure 6c), it broke within the gauge. Such behavior may suggest, that the aluminide layer is not responsible for crack initiation. Moreover, it protects the MAR 247 alloy against the high temperature exposure, and as a consequence, successfully extends its service life. One can indicate that good coherence between layer and substrate could further improve the mechanical response of matrix material [42].

3. Author need to include some more reference about interfacial adhesion of NiTi alloy with other materials such as below

Study of Interfacial Adhesion between Nickel-Titanium Shape Memory Alloy and a Polymer Matrix by Laser Surface Pattern, 2020/1, Applied Sciences, Volume 10, Issue 6, Pages 2172.

Authors included this publication under position [42].

Thank you very much indeed. If any other clarification is needed, I will be more than happy to provide an answer.

yours sincerely

Mateusz Kopec