Mechanical and Tribological Properties of Ni-B and Ni-B-W Coatings Prepared by Electroless Plating
, Yafeng Zhang, Huimin Qi and Dongwei Wang
G. C. Mondragón Rodríguez
Round 1
Reviewer 1 Report
Does not contain any new information. All these are available in literature for long (Ref. 31, 46 etc.)
It will not add any value to existing knowledge.
Author Response
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Reviewer 2 Report
Considering practical applications, the subject matter is very interesting and has a special value. The research methods and materials have been carefully characterized. For increase the quality of the paper I suggest a mandatory revision in the introduction part of the paper on following points:
Introduction:
1. To support this phrase from row 31: "However, wide application was limited by the poor hardness and abrasiveness...", you should replace bibliographic references [7] and [8], because reference [7] highlights only biocompatible titanium alloy structures for use as medical devices in some applications, in addition, do not investigate hardness and abrasiveness. Reference [8] is very old (from 1991), for justification replace it with an up-to-date source (in the last 5 years);
2. On row 32, you present research that modifies the surface through laser treatment. In the respective references, I see that there are only laser cladding experiments and laser metal deposition. You can start the phrase like this: "Deposition of coatings by laser applications [9, 10]...";
3. The reference from row 47 it is not current (it's [22] from 2004). If it's possible, please replace it;
4. Also, on rows 47 until 50 you say that:
- "However, Ni-B coating is limited by its poor corrosion resistance and toughness...", but the reference [23] presents a research for ternary Ni-B-W coatings;
- "In order to meet higher industrial requirements and adapt to more stringent application scenarios, multicomponent alloy coating was invented...", but reference [24] highlights only standard EN-B coatings;
5. From 64 row until 66 row you say that: "Furthermore, with the increase of annealing temperature, the grains grew up and phases decomposed, so that the hardness of the coating decreased", but the study from reference [44] reports only the effect of phosphorus content in deposited electroless nickel coatings and the influence of the temperature on the microstructure of the Mg alloy substrate. The same, in reference [45], I consider that it is all about the effect of phosphorus because we do not find phases such as Ni, Ni2B and Ni3B as you pointed out before.
Author Response
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Reviewer 3 Report
Characteristics (hardness, crystallines fases, thermal treatment?) of the TC4 alloy are required to understand the mechanical properties of the coatings on top of the system. In general, the discussion and analysis related to the properties mismatch should be addressed since the authors discuss fracture toughness.
The discussion related to the nano-hardness decrease is not clear. The conclusion cannot be alone based on the grain growth caused by annealing. The crystalline phases also play a major role in the coating properties. This should be also discussed.
For clariyt, details in the methodology section regarding the Vickers indentation are needed. I think it can be said that 10 N were applied for Vickers, but, it is not clear for the reader.
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Reviewer 4 Report
Ni-B and Ni-B-W coatings were deposited on TC4 substrate by electroless plating. The obtained coating has high hardness, good wear resistance and high fracture toughness. But there is a lack of relevant experimental data of TC4 substrate material. Experimental data such as wear volume, friction coefficient, wear morphology and wear form of TC4 substrate should be supplied and compared.
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Reviewer 5 Report
Dear Authurs
1. Lines 11-12. Please, what characteristics of the coating were improved by annealing? What is the purpose of this coating? Add, that TC4 is a titanium alloy.
2.Line 63. Is Nickea a hard phase in the coating? Or it is a base of the coating?
3. Figure 2. The coating roughness effects the results of EDS, especially if light elements should be detected. Did You polished the samples before this examination?
4. EDS is not reliable method to determibe the concentration of B. I think, this result should be checked by ramman spectromrtry, XPS or other method.
5. zline 128-129. Please, explain, in which cases You did more than 3 tests? For which samples, and what was the reason of this.
6. Table 3. What was the duration of annealing? How high temperature annealing effected the microstructure of TS4 alloy? DDid it caused the changi in microstructure? Please, add the corresponding micrographs.
7. Figure 3 should be recaptured after fine polishing using SEM. Higner magnification should be used to see the microstructure of the coating and the substrate.
8. Line 160. It seems like W content also improves the smoothnes of the coating, isn't it? Please, make the 3D map of the coating surface or measure its roughness to prove this.
9. Add the table with reliable data on the composition of the coatings, not the bath liquid.
10. Figure 6. The digits are too small, abd the pictures are bluring. Please, improve the quality and resolution. Make them bigger.
11. Please, do the wear test fot the substrate material, and compare the results with wear resistance of the coatings. Add the results to the article. Discuss is it efficient to deposit the coatings?
12. Figure 242-243, Figure 11. How these profiles were obtained? Were they measured in a speciefic point, or each of profiles is an avarage value of many profiles, made for each sample?
13. Figure 11. Enlarge the pictures. The figures are undistinguashable.
14. Figures 12-13. For detailed and comprehensive analyses of the friction surface, ADITIONAL micrographs with higher magnification (at least 3-5 times bigger than it is now). Especially fir the wear track in Fig. 12e.
15. The figure 10 is not discussed enough. There is significant difference between coatings prepared according to mode "0" and mode "3" (black and green lines). This difference should be explained.
16. In discussion of the wear mechanism, You just manifest, but do not explain the reasons of observed phenomena.
17. Line 276. What do You mean "cell body"? Line 280. Why the increase of annealing temperature causes the coating spallation?
18. Line 286. How did You detected this? Maybe, these words should be moved to the discussion of Fig. 10?
19. Line 296-297: "Both coatings showed amorphous structures, as well, possessed increased hardness values compared with the substrates". Please, indicate, that this is tru foe "as-deposited" condition only.
20. Line 302-303 : "The friction coefficient of annealed coatings was decreased with the increase of annealing temperature" But, Fig. 10 says opposite. Where is the correct statement?
Please, check the highlights in the manuscript, they contain aditional recomendations. The edditin of English style/gramma is required
Comments for author File: Comments.pdf
Author Response
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Round 2
Reviewer 1 Report
Authors argue that the substrate is titanium alloy that is novel. But it is well established in literature that electroless coating properties remain the same on all substrates. Changing the substrate does not yield any new property or variation in property hence no novelty.
Accordingly, there is lack of novelty in the manuscript. All these information are already available in literature (even in books like Electroless nickel plating: fundamentals to applications, Fabienne Delaunois, Veronique Vitry, Luiza Bonin, CRC press, 2020).
There are many other issues like: Equation 1 is missing although mentioned in text; it is not clear how fracture toughness is evaluated etc.
Reviewer 2 Report
Dear Authors,
I appreciate that you received the review as a constructive part for improving your paper. From my point of view I consider that for practical applications, the subject matter is very interesting and has a special value.
Reviewer 4 Report
Accept
Reviewer 5 Report
Thank You for the work done. So, I think the manuscript may be published
