Correlation of Tensile Properties of Arc-Sprayed Coatings and Easy Testing Methods

Round 1

Reviewer 1 Report

In this paper, the relationship between the tensile properties of arc spray coatings and simple test methods by means of tensile tests, Vickers hardness and Charpy impact tests, and some valuable results are provided. However, the following problems need to be solved before publication:

1.      Materials and Methods: only Title 2.2, Title 2.3 and Title 2.4, Title 2.1 is missing

2.      Page 4, line 124. Abbreviations that appear for the first time in the text should be provided in full.

3.      The box lines of the zoom area in Figure 4a and Figure 5a overlap with the text, making the figure confusing. It is recommended to separate the lines from the text.

4.      Is the red dashed part in Figure 5 including Figure 5b? It is recommended to clarify the lines in the figure to make it more aesthetically pleasing.

5.      Please seal Figure 6 to make it more standardized and beautiful.

6.      Page 5, lines 140-141. Where did the EDS data for “black arrows” ? Is it the EDS data represented by the red arrow in Figure 5a or Figure 5b?

7.      Page 6, line164. Does stainless steel refer to stainless steel coating? It is recommended that this be clearly stated to avoid ambiguity.

8.      Table 2 should be improved. Obviously, substrate is not belonged to coatings, so the column title of column 1 is not appropriate.

9.      “This result is explained by the more compact and homogeneous microstructure of Mo coating, presented in Figure 4. (lines 164-165) is mentioned in the text, how does it show that the microstructure of the Mo coating is more dense and homogeneous?

10.  Only qualitative correlation between yield strength and hardness was present in this paper. Actually, quantitative results are needed for engineering application.

The English should be improved.

Author Response

Comment 1. Materials and Methods: only Title 2.2, Title 2.3 and Title 2.4, Title 2.1 is missing

Response 1: This issue has fixed as suggested.

Comment 2. Page 4, line 124. Abbreviations that appear for the first time in the text should be provided in full.

Response 2:  The acronym HVOF was defined at the first appearition.

Comment 3. The box lines of the zoom area in Figure 4a and Figure 5a overlap with the text, making the figure confusing. It is recommended to separate the lines from the text.

Response 3:  Figures 4 and 5 were completely re-built. Thank you.

Comment 4 Is the red dashed part in Figure 5 including Figure 5b? It is recommended to clarify the lines in the figure to make it more aesthetically pleasing.

Response 4:  Figures 4 and 5 were completely re-built. Thank you.

Comment 5. Please seal Figure 6 to make it more standardized and beautiful.

Response 5:   Figure 6 was re-built. Thank you.

Comment 6. Page 5, lines 140-141. Where did the EDS data for “black arrows” ? Is it the EDS data represented by the red arrow in Figure 5a or Figure 5b?

Response 6:   Figures 4 and 5 were completely re-built. Thank you.

Comment 7. Page 6, line164. Does stainless steel refer to stainless steel coating? It is recommended that this be clearly stated to avoid ambiguity.

Response 7:   This issue has fixed as suggested.

Comment 8. Table 2 should be improved. Obviously, substrate is not belonged to coatings, so the column title of column 1 is not appropriate.

Response 8:   This issue has fixed as suggested.

Comment 9. “This result is explained by the more compact and homogeneous microstructure of Mo coating, presented in Figure 4. (lines 164-165) is mentioned in the text, how does it show that the microstructure of the Mo coating is more dense and homogeneous?

Response 9: the old sentence would be comparative. We have changed the text for better understanding. Hope to meet your suggestion.

Comment 10.  Only qualitative correlation between yield strength and hardness was present in this paper. Actually, quantitative results are needed for engineering application.

Response 10: We are sorry to not understand your request at this point. We have presented quantitative results for constraint factor, and the new version presents clearly the constraint factor definition, their values are quantitative results, and not qualitative.

Reviewer 2 Report

In this manuscript, the author deposited two types of metal coatings using arc-spray technology and discussed the relationship between the mechanical properties extracted from tensile tests and a simple method for representing material strength and toughness. It is better if the authors consider the following mentioned remarks and further improve the manuscript before submitting the final version

1. Aims of the work to be clearly defined and given at the end of Introduction chapter. 

2. Microstructural characterization: The red dashed line appears in Figure 5, and no black arrow is seen in Figure 5b.

3. Please explain how the constraint factor was obtained in this work.

4.The author should supplement the experimental data to explain the relationship between the microstructure of the coating and the yield strength, hardness and elongation. Otherwise, this work is only an experimental report and not scientific.

 

Author Response

Comment 1 Aims of the work to be clearly defined and given at the end of Introduction chapter. 

Response 1:    We have added a last paragraph to meet your request. Thank you.

Comment 2: Microstructural characterization: The red dashed line appears in Figure 5, and no black arrow is seen in Figure 5b.

Response 2:   Figures 4 and 5 were completely re-built.

Comment 3: Please explain how the constraint factor was obtained in this work.

Response 3:   Equation (1) has added in the manuscript, defining the constraint factor.

Comment 4:  The author should supplement the experimental data to explain the relationship between the microstructure of the coating and the yield strength, hardness and elongation. Otherwise, this work is only an experimental report and not scientific

Response 4:   Thank you for your comments. We have changed in many aspects for describing better the microstructure. Therefore, it was easier to correlate them with the mechanical properties.

Reviewer 3 Report

The article does not discuss the effects why the strengths increase with the deposition of arc spray coatings.

At this point of time this manuscript just resembles a lab report

 

The article does not discuss the effects why the strengths increase with the deposition of arc spray coatings.

At this point of time this manuscript just resembles a lab report

 

 

Author Response

We have appreciated your comments but all are generic. Please, check the improvements along with the whole manuscript, in which we have applied following the puctual suggestions of other reviewers. We believe that their implementation was enough to reach your consideration to turn a lab report into scientific article. Thank you very much.

Reviewer 4 Report

Manuscript ID: coatings-2363742 entitled:

Correlation of tensile properties of arc-sprayed coatings and easy testing methods

 

Authors: Rassim Younes , Abdelhek Idir , Mohand A. Bradai , Abdelhamid Saadeddine , Lidia Baiamonte , Giuseppe Pintaude

 

General comment

This paper presents the results of the different techniques are usually employed to evaluate the mechanical properties of mild steel substrate covered with an arc-sprayed layer obtained from X6CrNi18-8 and molybdenum.

Some recommendations and observation remain:

1. In Table 1 and 2 the unit is missing.

 

2. From figure 4 results that the W-rich phases seems to be present as lamellar shaped  phases or globular shaped phases embedded in the surrounding.  In addition, some defects are observed. Morphology should be describe more.

 

3. It is necessary to presents the quantitative EDS analysis at different spots of the representative coating microstructure and to reveal that the average coating content. The coating features an average content of ~12 wt. % of O (figure 5), suggesting the formation of oxides. In addition, the composition of the samples no more corresponds to the nominal composition of the feedstock. Can authors give more comments regarding these aspects?

 

4. As a result of the spraying process characteristics, the arc-sprayed coating is interstratified with various oxides and a suitable correlation is difficult cu find. Insert few details about possible oxides or formed ones.

 

5. In figures 4 and 5 the meaning of arrows are not clearly explained (ie the black arrows). For each explanation word, is more suggestive if the same color as of the arrow is used.

 

6. As the differences in hardness result from the non-uniformity in the structure of the coating and the different conditions of heat dissipation in the process of coating buildup, insert few comment about the micro hardness distribution and porosity of these coatings.

 

7.  Mention in the paper the value of constrain factors take from ref [13].

 

8. Check the references and update

Pintaude G. 2022,  Hardness as an Indicator of Material Strength: A Critical Review Crit. Rev. Solid State Mater. Sci,  pp. 1–19, https://doi.org/10.1080/10408436.2022.2085659

Author Response

Comment 1:  In Table 1 and 2 the unit is missing.

Response 1:  This issue has fixed as suggested.

Comment 2:  From figure 4 results that the W-rich phases seems to be present as lamellar shaped phases or globular shaped phases embedded in the surrounding. In addition, some defects are observed. Morphology should be describe more.

Response 2:   Figures 4 and 5 were completely re-built, as well as the description of microstructures. Thank you.

Comment 3:  It is necessary to presents the quantitative EDS analysis at different spots of the representative coating microstructure and to reveal that the average coating content. The coating features an average content of ~12 wt. % of O (figure 5), suggesting the formation of oxides. In addition, the composition of the samples no more corresponds to the nominal composition of the feedstock. Can authors give more comments regarding these aspects?

Response 3:   Figures 4 and 5 were completely re-built, as well as the description of microstructures. Thank you.

Comment 4:  As a result of the spraying process characteristics, the arc-sprayed coating is interstratified with various oxides and a suitable correlation is difficult cu find. Insert few details about possible oxides or formed ones.

Response 4:   Figures 4 and 5 were completely re-built, as well as the description of microstructures. Thank you.

Comment 5:  In figures 4 and 5 the meaning of arrows are not clearly explained (ie the black arrows). For each explanation word, is more suggestive if the same color as of the arrow is used.

Response 5:   Figures 4 and 5 were completely re-built, as well as the description of microstructures. Thank you.

Comment 6:  As the differences in hardness result from the non-uniformity in the structure of the coating and the different conditions of heat dissipation in the process of coating buildup, insert few comment about the micro hardness distribution and porosity of these coatings.

Response 6:   We have added a new figure describing the hardness profiles of coatings. Thank you very much for your helpful suggestion.

Comment 7:  Mention in the paper the value of constrain factors take from ref [13].

Response 7:   These values are presented in Figure 8 (rebuilt), previous Figure 7. Thank you very much for your helpful suggestion.

Comment 8:  Check the references and update

Pintaude G. 2022,  Hardness as an Indicator of Material Strength: A Critical Review Crit. Rev. Solid State Mater. Sci,  pp. 1–19, https://doi.org/10.1080/10408436.2022.2085659

Response 8:   This issue has fixed as suggested.

Round 2

Reviewer 1 Report

The paper can be accepted now.

Minor editing of English language required

Reviewer 2 Report

The author has fully responded to my suggestions and I agree to publish this manuscript

Reviewer 3 Report

The revised manuscript can be accepted for publication

The revised manuscript can be accepted for publication

 

Reviewer 4 Report

Accept in present form