Effect of Heat Treatment on the Cavitation Erosion Performance of WC–12Co Coatings

Round 1

Reviewer 1 Report

Dear authors,

Thank you for well designed and conducted research.

There are some comments I have to point out:
1. The Introduction and Discussion parts are lacking the explanation of the necessity of heat-treatment for WC-Co HVOF systems. It is not clear that was the motivation for the research, obviously the phase transformation is obvious link here, but there are no discussion of possible phase transformations is given. Please consider of adding the part for justification of the proposed research hypothesis - effect of heat-treatment on cavitation erosion resistance;

2. The Introduction and Discussion parts are lacking the discussion and comparison of the WC-12Co HVOF coatings cavitation erosion published results, for example researches of Xiang DingDu Ke et al "Microstructure and Cavitation Erosion Resistance of HVOF Deposited WC-Co Coatings with Different Sized WC"(Coatings 2018, 8, 307; doi:10.3390/coatings8090307) and Zhang-xiongDING et al. "Resistance of cavitation erosion of multimodal WC-12Co coatings sprayed by HVOF, Transactions of Nonferrous Metals Society of China, Vol 21, Issue 10, Pages 2231-2236, doi.org/10.1016/S1003-6326(11)61000-5, which also give better justification of the research results;

3. The results shown in Fig 12 are for different conditions, this is why the points on the graph can not be fitted by curves, but rather results should be presented as separate, for example as shown in Fig. 6;

4. Figs 11 and 12 should be placed more close to the related text, for example lines 209 and 213 respectively.

Best regards,

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

I have read your manuscript with attention and great interest. The subject is needed and up to date. During the reading, a few comments came to my mind that may complement your work.

Title: Change “Heat-Treatment” to „Heat treatment”

1. Although the Introduction chapter is written correctly, it is not very long and can be extended by citing current works from Coatings, which can certainly contribute to a better discussion in the field of coating cavitation erosion. MDPI Publishing House is known for publishing sequences of articles on similar subjects. I am convinced that participation in this is beneficial for the authors. Over the past two years, the following papers have been published that can be a source of information for Introduction and Summary.

https://doi.org/10.3390/coatings8070254

https://doi.org/10.3390/coatings9090534

https://doi.org/10.3390/coatings9050340

https://doi.org/10.3390/coatings8100346

https://doi.org/10.3390/coatings8090307

2. I have one big remark to the erosion model - it is very general. Please specify it - it suits every spray coating and every layer with defects - even to a surface weld (Fe-WC or Ni-WC type, after all, there may also be cracks and pores).

From the presented research and their results, you can certainly draw more valuable conclusions, highlight work novelty. In its present form, the article is primarily a research report.

The conclusions should be rearranged so that they describe specific results obtained in the thesis. In their present form, they are rather generally formulated, well-known statements, suitable for any type of spray coating.

Detailed remarks:

3. Table 1: change L/h to l/h and value to Value

4. Line 52: “Commercial WC-12Co powder was used as feedstock for HVOF spray”. This statement is too general. Please provide a detailed description of the powder.

5. Line 59: The description of the spraying process also requires a broader, deeper description. What were the dimensions of the samples? What is the chemical composition of the substrate?

6. Line 63: Have the surface roughness values of the steel been measured before and after sand blasting?

7. Figure 6: Please fill in the information on what error the error bars show. Standard deviation?

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear Authors, 

1. Thank you for taking into account most of my comments. However, I note again that most of the scientific sources cited come from Asia. Due to the fact that it is good scientific practice to take care of the balance and representativeness of research centers from around the world, I strongly suggest citing the articles of scientists from Europe. I am convinced that this will contribute to the citation of the article.

Best regards

Author Response

Please see the attachment.

Author Response File: Author Response.pdf