Effects of PVD CrAlN/(CrAlB)N/CrAlN Coating on Pin–Disc Friction Properties of Ti2AlNb Alloys Compared to WC/Co Carbide at Evaluated Temperatures
, Lirui Zheng 1,2,3,4, Wenqian Li 1,2,3,4, Zhanqiang Liu 1,2,4,5,*, Liangliang Li 6,7, Bing Wang 1,2,3,4, Yukui Cai 1,2,3,4, Xiaoping Ren 1,2,3,4 and Xiaoliang Liang 1,2,3,4Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript's authors, "Effects of PVD CrAlN/(CrAlB)N/CrAlN coating on pin-disc friction properties of Ti2AlNb alloys compared to WC/Co carbide at evaluated temperatures", undertake the interesting subject. The manuscript is clearly presented and well organized. The investigation methodology is consistent with this type of investigation, and some valuable results can form the basis for publication. The paper is original and interesting, although it does not present a breakthrough in the field. However, I suggest publishing recent work as an original article.
Major revisions of the manuscript must be considered for acceptance:
1) A significant disadvantage of the EDS method is the difficulty in examining light elements such as boron, carbon, and nitrogen. However, having selected appropriate process parameters, the analysis of boron content is possible. How did the Authors analyze the chemical composition using EDS (with what parameters)? Shouldn't the presence of boron in the coating be confirmed using another (more accurate method), e.g., XPS?
2) In Fig. 2d,e,f, the Authors show the chemical composition of layers. Suppose the presence of carbon (C) was demonstrated. Why did the authors not also consistently demonstrate the presence of oxygen (O), which is undoubtedly present (in large quantities) in the analyzed layers?
3) Fig. 4 – in my opinion, the Authors have incorrectly designated the load Lc1. The value of Lc1 (82,36 N) is too high. The load at which the first coating defects appear is known as the first critical load Lc1. The first critical load Lc1 corresponds to the point at which first damage is observed; the first appearance of microcracking, surface flaking outside or inside the track without any exposure of the substrate material - the first cohesion - related failure event.
4) There are many syntax and typing errors in the text. Please revise it carefully.
Author Response
Dear respected reviewer,
Thank you for your email letter dated May 17th, 2024. We are pleased to know that our manuscript (metals-3023250) has been rated as major revision for publication in metals. Based on the instructions provided in your email letter, we uploaded the revised manuscript with the whole corrections highlighted by using the track changes mode in red color.
Appended to this letter is our responses for the comments referred in your email letter. The comments are reproduced and our responses are given directly afterward.
We hope that the revised manuscript could be accepted and published in the International Journal of Machine Tools and Manufacture.
Yours Sincerely
Prof./Dr. Jinfu Zhao
Prof./Dr. Zhanqiang Liu
Shandong University, China
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsA promising way to improve the performance characteristics of parts is the use of wear-resistant coatings that protect their contact surfaces from high temperatures. High performance characteristics of coated parts are determined both by the properties of the coating - high hardness, heat resistance, inertness to the material being processed, and by the specified properties of the base - fatigue resistance, etc.
In the article, the authors obtained the main patterns of reciprocating friction between the Ti2AlNb alloy and a pair of WC/Co carbide tools with a single PVD CrAlN/(CrAlB)N/CrAlN coating option in the temperature range of 25–600 ºC. The antifriction properties of Ti2AlNb alloy were evaluated using time-varying friction coefficients, alloy wear rate, worn surface topography, worn surface features, and wear mechanism analysis. The results indicate that the CrAlN/(CrAlB)N/CrAlN PVD coating reduces the average coefficient of friction and wear rate of the alloy compared to an uncoated WC/Co carbide pair. The results of the article are useful for science and practice. But there are several questions:
1. What was the surface roughness of worn Ti2AlNb alloy with uncoated carbide specimen before and after tests at 25...600 oC?
2. In order to assess the homogeneity of PVD CrAlN/(CrAlB)N/CrAlN coating, it might be worthwhile to conduct its nanoindentation and statistical analysis received data. Perhaps the authors controlled the uniformity of the coating's properties in some other way?
3. Scale in Fig. 5 propose to indicate by numbers, with one sign after the dot.
4. Is it possible to develop a mathematical model and computer implementation of numerical methods for assessing its applicability for predicting the chemical and phase composition of coatings?
What data from the authors can be described mathematically?
5. It might be worth adding a table with a description to the article the relationship between the physical and mechanical properties of the coating with its chemical and phase compositions and its behaviour during wear in different temperature conditions.
Author Response
Dear respected reviewer,
Thank you for your email letter dated May 17th, 2024. We are pleased to know that our manuscript (metals-3023250) has been rated as major revision for publication in metals. Based on the instructions provided in your email letter, we uploaded the revised manuscript with the whole corrections highlighted by using the track changes mode in red color.
Appended to this letter is our responses for the comments referred in your email letter. The comments are reproduced and our responses are given directly afterward.
We hope that the revised manuscript could be accepted and published in the International Journal of Machine Tools and Manufacture.
Yours Sincerely
Prof./Dr. Jinfu Zhao
Prof./Dr. Zhanqiang Liu
Shandong University, China
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe authors have reported the linear reciprocating pin-disc friction tests between Ti2AlNb alloy and WC/Co carbide tool coupled with the sole variation of PVD CrAlN/(CrAlB)N/CrAlN coating that were conducted within the wide ranges of temperature 25-600 ºC. The manuscript can be further improved by incorporating the following suggestions:
1. Please provide the deposition temperature for CrAlN/(CrAlB)N/CrAlN coating.
2. What are the process gases used to develop CrAlN/(CrAlB)N/CrAlN coating?
3. What is the flow rate of these process gas?
4. What was the deposition pressure for CrAlN/(CrAlB)N/CrAlN coating?
5. Please mention above details for each coating 1 to coating 5.
6. Please provide make and model details of the XRD instrument.
7. Please provide JCPDS reference number for the CrAlN or (CrAlB)N and CrAlN/(CrAlB)N/CrAlN coatings.
8. Please represent the XRD spectrum as a separate figure, include relevant scientific discussion and references confirming the observations reported for XRD results.
9. How many EDS measurements were taken for figure 2?
10. Explain how the authors were able to differentiate and quantify the following in figure 2: (d) the main chemical element composition of surface layer; (e) main chemical element composition intermediate layer; (f) main chemical element composition of bottom layer.
11. Please include the elemental mapping image for figure 3 to confirm the presence and distribution of the respective elements.
12. The results and discussion section contains only 1 new citation, and 32 citations are used in introduction. The results and discussion section seems like a detail report on the experimental observation only. Please modify it by including relevant scientific discussion that is referenced with relevant citations confirming the observations reported in this section.
Comments on the Quality of English LanguageThe quality of English language is good.
Author Response
Dear respected reviewer,
Thank you for your email letter dated May 17th, 2024. We are pleased to know that our manuscript (metals-3023250) has been rated as major revision for publication in metals. Based on the instructions provided in your email letter, we uploaded the revised manuscript with the whole corrections highlighted by using the track changes mode in red color.
Appended to this letter is our responses for the comments referred in your email letter. The comments are reproduced and our responses are given directly afterward.
We hope that the revised manuscript could be accepted and published in the International Journal of Machine Tools and Manufacture.
Yours Sincerely
Prof./Dr. Jinfu Zhao
Prof./Dr. Zhanqiang Liu
Shandong University, China
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe Authors have effectively responded to all the concerns found in the first version of the manuscript. The revised manuscript has improved a lot upon the original, following my main suggestions and comments. I feel that the revised paper deserves publication in "Metals" journal.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscripts looks better and the quality of it has improved after incorporating the suggestions, the authors did a good job, the manuscript can be accepted in the present form.
