Manufacture and Characterization of Geopolymer Coatings Deposited from Suspensions on Aluminium Substrates

Round 1

Reviewer 1 Report

The paper by Novotný et al. reports the experimental characterization of different alkali-activated metakaolin-based geopolymers used as brush-applied coatings on aluminum substrates. The paper is well-written, the experiments were well conducted and the results are clearly presented and commented. I suggest to accept the paper after a careful text editing to correct some typos and errors and to check English language

Author Response

Dear Reviewer,

thank you very much for your time, for your opinion and for the very positive rating of our manuscript. We will try to recheck our English language and typos correction. You can see the changes in the manuscript highlighted with pink color.

Best regards.

Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

I reviewed your manuscript proposed to publishing in Coatings Journal. The reviewed manuscript focuses on a very interesting issue, which is the use of geopolimers as coatings on metal materials as a corrosion resistance layer. Stucture of manuscript is correct and include all nessecery elements such as: intrucuction to analysed field, methodology of experiments, description of results with some discussion and conclusions.

Generally, I have a several comments and sugestions, which are present below:

1) Introduction. Authors in this chapter not enough introduce to analysed issue. I my opinion there should be presented more discoussion about analysed material and its anizotropic properties, especially for that thin material and manufactured by cold rolling. Residual stresses after this manufacture proces has effect on a several properties of this material (mechanical, machinability, etc.). Do residual steresses have effect on adhesion properties?

Hattori, N.; Matsumoto, R.; Utsunomiya, H. Residual Stress Distribution through Thickness in Cold-Rolled Aluminum Sheet. Key Eng. Mater. 2014, 622-623, 1000–1007. DOI: 10.4028/www.scientific.net/KEM.622-623.1000.

Chuchala, D.; Dobrzynski, M.; Pimenov, D.Y.; Orlowski, K.A.; Krolczyk, G.; Giasin, K. Surface Roughness Evaluation in Thin EN AW-6086-T6 Alloy Plates after Face Milling Process with Different Strategies. Materials 2021, 14, 3036. https://doi.org/10.3390/ma14113036

Robinson, J. S.; Pirling, T.; Truman, C. E.; Panzner, T. Residual Stress Relief in the Aluminium Alloy 7075. Mater. Manuf. Processes. 2017, 33(15), 1765–1775. DOI: 10.1080/02670836.2017.1318243.

2) In introduction Author call a lot of references, but not discribed them enough. For example: "Adhesion properties are described in [30–44]." 6 references in one sentence. Did all references discusse about the same issue?

3) Material. 3) Material. There is a lack of information on the preparation of the samples made of aluminium alloy. Information on the diameter of the round bars is also missing. Were the surfaces of the materials somehow treated/machining before the coatings were applied? Were the natural oxides formed on the surface of the material during storage removed?

4) Table 1. Source of data is missing

5) Chapter 2.2. The procedure for measuring surface roughness is not described in detail. What were the measuring sections? What was the size of the measuring pin, etc.

6) Table 5 and 7. What this means ± ? spreads of results?

7) Figures 9-14. illegible descriptions of graphs and individual functions

Author Response

Dear Reviewer,

thank you very much for your time, comments and for your opinion. We are focused on all points, especially on Introduction and references.

As you wrote, the introduction lacks information’s about mechanical properties of the underlying substrate, which was added. Information has been added especially from the references which you are submit.

Paragraph in the introduction ending with sentence “Adhesion properties are described in [30–44]” supported by references [30 – 44] was described only in citation [32]. The sentence was supposed to express only the general review. In any case this sentence was misleading. However, in our opinion the discussed issues is correct in the introduction.

Points 1 – 7 was edited and highlighted with your color (green).

Best regards.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments of coatings-1997899

The main weaknesses of the manuscript:

1.     The introduction fails to highlight the importance of this study, the significance of the article needs to be increased and the highlight is prominent.

2.     How accurate is the thickness measurement? What causes the thickness difference of the M specimen to be too large?

3.     Abstract and introduction in the manuscript and described that the corrosion resistance is an important factor of the coating. Why is corrosion resistance not discussed in this study? Please add and explain.

4.     The scale ruler in Figure 4 is not clear.

Comments for author File: Comments.pdf

Author Response

Dear Reviewer,

thank you very much for your time and for your opinion. Your comments about our manuscript weakness are very important. We focused on all points and tried to accommodate on all of them.  The original intention was to verify the corrosion protection, but finally we preferred to focus on a detailed analysis of the dilatation properties of the coatings. The corrosion protection will be studied in the future work and sentence about corrosion in abstract was deleted. It is our fault that we included this sentence into the abstract. The Corrosion is not the part of the research in this study. We also add the importance of our study into introduction and scale ruler in figure 4 and specifications about thickness measurement was also edit and highlight with yellow color.

Best regards.

Author Response File: Author Response.docx

Reviewer 4 Report

The article is interesting, but I have some comments and suggestions.

The paper presents the research results of 8 different geopolymers suspensions, while the title suggests that the work is a literature review. I suggest changing the title.

In my opinion the aim of the work should be determined at the end of Introduction, not only in the Abstract.

The explanations in Fig. 10 - 14 are not legible.

Author Response

Dear Reviewer,

thank you very much for your time and for your opinion. We took your comments and suggestions very seriously. Our research results bring modern insights about geopolymers coatings and it’s not only literature review. We changed the title based on this recommend. We also edit the abstract and Figures 9 – 14 have been edited into publishable form. You can see the editing in the manuscript highlighted with blue color.

Best regards.

Author Response File: Author Response.docx