Investigating the Water Jet Erosion Performance of HVOF-Sprayed WC-10Co Coatings on 35CrMo Steel Utilizing Design of Experiments
, Abdul Aabid 6, Muneer Baig 6 and Bahaa Saleh 7Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
This study evaluate the erosion resistance of the WC-10Co coatings prepared by HVOF. Overall, the manuscript is lack of organization and poor in quality. I found several drawbacks in this manuscript that need to be addressed. First, the manuscript is not well-organized. The Experimental and the Results seems to be mixed together, and the methodology are not clearly described. The authors must revise the statement completely to improve the quality of the manuscript. Second, there are a lot of questionable and unclear statement throughout the manuscript. For example, in Page 4, the authors stated that the thickness and adhesion of the coating can be determined by the surface image of the coating. This is absolutely wrong. The authors must check the manuscript thoroughly to ensure the scientific soundness of this study. Lastly, the results of the micro hardness measurement and bonding test are completely missing. In addition, the captions of Fig. 6 to Fig. 9 are even the same. Grammatical errors are commonly found throughout the manuscript. It seems that the manuscript are not carefully check and polished. Since this study needs a completely modification and additional experiments are also required, I must reject this manuscript for publication. My other comments on this manuscript are listed below.
Page 1: “Research scholar, Department of Mechanical Engineering, Noorul Islam Centre For Higher Education, Kumaracoil, Tamil Nadu -629180”
The titles of all the authors should not be shown in the affiliations. In addition, the country of the affiliation should be added.
Page 1: “On a 35CrMo steel substrate, WC-10Co coatings were coated using the HVOF thermal spraying process.”
The abbreviation “HVOF” should be spelled out upon first appearance in the abstract.
Page 1: “Keywords: WC-10Co coating, HVOF, Erosion rate, Stainless steel, Response Surface Methodolog”
Please revise “Methodolog” to “Methodology”.
Page 2: “WC-10Co powders deposited on a 35CrMo steel base material surface with a 200 micron thickness using HVOF spray equipment available at Annamalai University in India (HIPOJET-2700, Make: Metallizing Equipment Co. Jodhpur, India).”
The thickness of the substrate should be added in the sentence.
Page 2: “After that, a digital micrometre (precise 0.001mm) was utilized to estimate the coating thickness for every normal operating circumstance.”
Please revise “micrometre” to “micrometer”.
Page 2: “Prior to spraying, the base material was preheated achieved at 0.8 m/s through one complete torch cycle, attaining the 120–180°C.”
The meaning of the “0.8 m/s” is not clear. Furthermore, the authors should explain why preheat is needed for the substrate before the spraying process.
Page 2: “The base material surface roughness was improved using corundum (size of 320 ± 500 μm).”
Do you mean “The surface roughness of the base material was improved by grit blasting using corundum with size of 320 ± 500 μm.”?
Page 3: “The base material was found 5-10m after grit blasting using a surface roughness instrument (Make: Mitutoyo, Japan; Model: Surf test 301).”
The meaning of the “5-10m” is not clear.
Page 3: “SEM study (Make: JEOL, Japan; Model: 6410-LV) was utilized to examine surface characteristics and morphologies of powder and coating properties.”
The abbreviation “SEM” should be spelled out upon first appearance in the main text.
Page 3: “Figure 2(a-b) depictsan optical microscope view of the as coated powder with spherical form with particle sizes of –45+15μm.”
Please revise “as coated” to “as-coated” or “as-sprayed”.
Page 4: “SEM micrographs revealed that the coating was relatively thick and in excellent adhesion with the uncoated substrate as seen in Figure 2(c – d).”
It is not possible to evaluate the thickness and the adhesion of the coating by the surface examination.
Page 4: “This means that the deposition adheres well to the surface of the base material owing to the high velocity of thermal spray.”
The authors must carried out the results of the adhesion tests to support this statement.
Page 4: “In general, the amount of porosities produced in the coatings via HVOF is incredibly low.”
Please revise “incredibly” to “very”.
Page 4: “A micro hardness measurement (Make: Shimadzu; Japan) was used to determine the coating's micro hardness. Model: HMV-2T) with a 2.94 N load and a 15s holding time.”
The results of the micro hardness measurement is missing in this manuscript.
Page 5: “Figure 3 illustrates the pictures were assessed utilizing image processing software.”
No detail description on Fig. 3?
Page 5: “The bonding capability of the coatings was monitored in accordance with ASTMC-633-01 [35]. The deposition layer was bonded to the 35CrMo steel using E7 adhesive.”
Where are the results of the bonding test?
Page 6: “The coated and uncoated specimens mass loss were examined using water jet erosion apparatus (Model: TR- 411, Make: DUCOM, India) to study the impact of angle of impingement,…”
A picture showing the water jet erosion apparatus used in this study should be added into the manuscript for the readers’ reference. In addition, the testing standard of the erosion test should also be added into the manuscript (if any).
Figure 1:
The resolution of Fig. 1a must be improved. In addition, a scale should be added in Fig. 1b.
Figure 2:
I suggest delete Fig. 2b and 2d and add a table showing the results of EDS analysis of the powder and the coating.
Figure 3:
The resolution of all the figures are low. Furthermore, there is no statement describing Fig. 3b and 3c in the manuscript.
Figure 4:
Scales should be added in Fig. 4b and 4c.
Figure 6-9:
The figure captions of all these figures are all the same. Please revise.
Author Response
Dear Reviewer, Greetings. Herewith i am submitting the responses of the comments asked by the reviewer. All the corrections were carriedout in the manuscript and highlighted. Hence I request you to accept my manuscript. Thanks for your valuable comments and suggestions. Thanks
Author Response File: 
Author Response.pdf
Reviewer 2 Report
- In the abstract High-Velocity Oxy-Fuel (HVOF) should also be written.
- The introduction needs to be improved and the authors need to describe the novelty of this manuscript. Moreover, the authors must state the difference between this manuscript and the one published, not reported in the references, on Materials Today: Proceedings, entitled “Influence of rotational speed, angle of impingement, concentration of slurry and exposure time on erosion performance of HVOF sprayed cermet coatings on 35CrMo steel”.
- Lines 148-151. “ With the assistance of a suitable work holding device, at the necessary radial distance, these specimens were mounted to the disc. Along with the specimen, the disc is immersed into the slurry in the container. The specimens are rotated through starting the motor at the required speed for a specified duration”. I donn’t undertaand this part.
- Line 96. “The base material was found 5-10m after grit blasting using a surface roughness instrument”. Explain this sentence better.
- Lines 104-105. “Figure 2(a-b) depicts an optical microscope view of the as coated powder…” Not optical but SEM. In the caption, it is written SEM.
- All the SEM images need to be improved, they are blurry.
- The caption in Figures 6-9 must be improved. The water jet velocity, impact angle etc must be written. Sections 4.1 to 4.4 are difficult to follow without this information.
- Lines 207-208. “The micro cutting and wedges seen in SEM images (Figure 6c). At moderate angles, ductile metallic material shows such kind of pattern”. Explain better this sentence.
- Lines 218-219. “During erosion impact, the ductile or brittle mechanism by which material is removed from a surface”. Explain better this sentence.
- Line 276-277. “The rate of metal removal has been observed to be significantly affected by stand-off distance”. From the data reported in table 3 does not appear to be true. The difference is either minimal or statistically irrelevant. IF we compare for example samples 1 -2 with 5-6, the difference is minimal. Even if the speed is increased (samples 3-4 with 7-8) the difference appears irrelevant. You should report the standard deviation
- Lines 332-333. “Erosion rates grow in a linear relationship with rising erodent discharge and diminish as the angle of impingement rises”. From the data reported in table 3 does not appear to be true. The difference is either minimal or statistically irrelevant.
- AFM analysis was not reported in the experimental section.
- In light of the abovementioned comments, the conclusions need to be improved.
Author Response
Dear Reviewer, Greetings. Herewith i am submitting the responses of the comments asked by the reviewer. All the corrections were carriedout in the manuscript and highlighted. Hence I request you to accept my manuscript. Thanks for your valuable comments and suggestions. Thanks
Author Response File: Author Response.pdf
Reviewer 3 Report
Before the work is considered to be published, some problems should be addressed.
Comments for author File: Comments.pdf
Author Response
Dear Reviewer, Greetings. Herewith i am submitting the responses of the comments asked by the reviewer. All the corrections were carriedout in the manuscript and highlighted. Hence I request you to accept my manuscript. Thanks for your valuable comments and suggestions. Thanks
Author Response File: Author Response.pdf
Reviewer 4 Report
The HVOF sprayed WC-10Co coating perpared on 35CrMo steel was evaluated by water jue erosion test. The erosion rate was investigated using water jet variables, including angle of impingement, water jet velocity, standoff distance, and erodent discharge. This is a systematically work and was well organized. It can be accepted for publication after minor revisrion. The figures should be well organized. Many figures are too obscure or to be recognized, such as Figs. 3, 4c, 10-13.
Author Response
Dear Reviewer, Greetings. Herewith i am submitting the responses of the comments asked by the reviewer. All the corrections were carriedout in the manuscript and highlighted. Hence I request you to accept my manuscript. Thanks for your valuable comments and suggestions. Thanks
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have successfully addressed the reviewer’s comments. The revised manuscript has meet the requirement for publication.
Reviewer 2 Report
All questions and doubts were sufficiently addressed. The manuscript can be published in its current form.
Reviewer 3 Report
After revision by the authors, I think the paper can be acceptable and published. But the final decision is up to the editor.
