The Effect of Laser Nitriding on Surface Characteristics and Wear Resistance of NiTi Alloy with Low Power Fiber Laser
Round 1
Reviewer 1 Report
The abstract is general. More important test results can be added.
There is Figure 1 with the schematic diagram of the laser nitriding process on NiTi alloy, however, no information about this scheme was found in the text of the article. Please add, some information for this figure.
How were the parameters Ra and Rz measured?
I do not fully understand the sense of the added mapping photos, because they were not commented on in the text.
In addition, if the mapping photos are at the same magnification as the samples? there is no scale bar on them.
To find out the homogeneity of the distribution of elements on the surface, it is also worth taking photos at higher magnification.
The article does not compare the results with the literature.
In some parts there is only a description of the results presented in the charts, no additional comment on the trends?
Correct typos and punctuations, e.g. "Fig. 4 The cross-section SEM images of NiTi alloy after laser nitriding." (line 115) -
I think it should be: "...after laser nitriding:"
In the conclusion section, the first sentence is: This section is not mandatory, but can be added to the manuscript if
the discussion is unusually long or complex, rather, it shouldn't be in the article.
The article presents research results, but there is no interpretation of them.
Author Response
1.The abstract is general. More important test results can be added.
Response: Thanks a lot. The abstract has been revised.
2.There is Figure 1 with the schematic diagram of the laser nitriding process on NiTi alloy, however, no information about this scheme was found in the text of the article. Please add, some information for this figure.
Response: Thanks a lot. A description of the schematic diagram has been added to the article.
3.How were the parameters Ra and Rz measured?
Response: Thanks a lot. The Perthometer M1 (Mahr) device for roughness measurement was used to test the surface roughness. The device has been added to the paper.
4.I do not fully understand the sense of the added mapping photos, because they were not commented on in the text.
Response: Thanks a lot. The comments have been added to the paper.
5.In addition, if the mapping photos are at the same magnification as the samples? there is no scale bar on them.
Response: Thanks a lot. The new scale bar has been added in the mapping photos.
6.To find out the homogeneity of the distribution of elements on the surface, it is also worth taking photos at higher magnification.
Response: Thanks a lot. Yes, the EDX mapping with higher magnification can observe more details of the homogeneity of the distribution of elements. The new measurement has to be done in another group and takes a longer time to wait for the instrument reservation. We will do the EDX mapping with higher magnification in our next research about laser nitriding.
7.The article does not compare the results with the literature.
Response: The results of this research is different from the literature. For example, compared with the paper "Formation of TiN Grid on NiTi by Laser Gas Nitriding for Improving Wear Resistance in Hanks' Solution" the thickness of nitride layer is much thicker in our research. The thickness of the TiN layer is about 1.76 um in the literature, but the thickness of the TiN layer in our research can reach 65 µm when we used a lower energy laser of 50 W.
8.In some parts there is only a description of the results presented in the charts, no additional comment on the trends?
Response: Thanks a lot. The additional comments have been added in the paper.
9.Correct typos and punctuations, e.g. "Fig. 4 The cross-section SEM images of NiTi alloy after laser nitriding." (line 115) –
Response: Thanks a lot. The punctuations have been corrected.
10.I think it should be: "...after laser nitriding:"
Response: Thanks a lot. The punctuations have been corrected.
11.In the conclusion section, the first sentence is: This section is not mandatory, but can be added to the manuscript if the discussion is unusually long or complex, rather, it shouldn't be in the article.
Response: Thanks a lot. The text has been deleted.
12.The article presents research results, but there is no interpretation of them.
Response: Thanks a lot. More analysis of the results has been added in the paper.
Reviewer 2 Report
The author has studied the effect of laser nitriding for enhancing the surface characteristics with a low power fibre laser.
1) Author must reorganise and redesign this study as in present form the study is not very clear. English language too should improve a lot. There is a lot of grammatical and sentence framing error. (Example Line 135 to 139 - The framed sentence is too long and this should be explained with shorter sentences. )
2) There are many authors done very similar research on laser nitriding and has reported the effect of it. The author must clearly mention how this study is different from a previous study done by other authors.
Chan, Chi-Wai, et al. "Fibre laser nitriding of titanium and its alloy in open atmosphere for orthopaedic implant applications: Investigations on surface quality, microstructure and tribological properties." Surface and Coatings Technology 309 (2017): 628-640.
Xu, J. L., et al. "Microstructure, corrosion resistance and formation mechanism of alumina micro-arc oxidation coatings on sintered NdFeB permanent magnets." Surface and Coatings Technology 309 (2017): 621-627.
Wang, H. M., and Y. F. Liu. "Microstructure and wear resistance of laser clad Ti5Si3/NiTi2 intermetallic composite coating on titanium alloy." Materials Science and Engineering: A 338.1-2 (2002): 126-132.
3) Abstract section is not very clear and it's very hard to follow the way sentences and study is reported.
4) Author has varied the laser parameter mentioned as S1 to S4. It would be better if the author mentions this instead of mentioning the scanning speed and frequency throughout the paper. (Example line 80, 104 all this can be just mentioned as S3 shows better result instead of mentioning 40mm/s and 200 kHz every time.
5) In conclusion section Line 181- the author has used the sentence that this section is not mandatory. Using such a sentence in the scientific journal is not appropriate.
6) Author must reorganise this study and also it would be better if the author takes professional help for English correction.
Author Response
The author has studied the effect of laser nitriding for enhancing the surface characteristics with a low power fibre laser.
1) Author must reorganise and redesign this study as in present form the study is not very clear. English language too should improve a lot. There is a lot of grammatical and sentence framing error. (Example Line 135 to 139 - The framed sentence is too long and this should be explained with shorter sentences. )
Response: Thanks a lot. The sentence has been changed.
2) There are many authors done very similar research on laser nitriding and has reported the effect of it. The author must clearly mention how this study is different from a previous study done by other authors.
Chan, Chi-Wai, et al. "Fibre laser nitriding of titanium and its alloy in open atmosphere for orthopaedic implant applications: Investigations on surface quality, microstructure and tribological properties." Surface and Coatings Technology 309 (2017): 628-640.
Xu, J. L., et al. "Microstructure, corrosion resistance and formation mechanism of alumina micro-arc oxidation coatings on sintered NdFeB permanent magnets." Surface and Coatings Technology 309 (2017): 621-627.
Wang, H. M., and Y. F. Liu. "Microstructure and wear resistance of laser clad Ti5Si3/NiTi2 intermetallic composite coating on titanium alloy." Materials Science and Engineering: A 338.1-2 (2002): 126-132.
Response: Thanks a lot. The NiTi alloy was processed at room and low temperatures to study the effect of room and low temperature on the laser nitriding in our research. In addition, the specimens in the previous study, such as Ti6Al4V alloy and BT9 titanium alloy, are different from the NiTi alloy in our research. For example, in the research of “Microstructure and wear resistance of laser clad Ti5Si3/NiTi2 intermetallic composite coating on titanium alloy” the researchers used the laser cladding with powder of commercial pure elemental powder blends of Ni, Ti, and Si to generate a new layer on the surface of BT titanium alloy to improve its wear resistance. The laser cladding is very different from the laser nitriding in our research. They are different treatment processes. We just processed the NiTi alloy with low energy fiber layer in nitrogen gas without any other powder.
3) Abstract section is not very clear and it's very hard to follow the way sentences and study is reported.
Response: Thanks a lot. The abstract has been revised.
4) Author has varied the laser parameter mentioned as S1 to S4. It would be better if the author mentions this instead of mentioning the scanning speed and frequency throughout the paper. (Example line 80, 104 all this can be just mentioned as S3 shows better result instead of mentioning 40mm/s and 200 kHz every time.
Response: Thanks a lot. The description has been revised.
5) In conclusion section Line 181- the author has used the sentence that this section is not mandatory. Using such a sentence in the scientific journal is not appropriate.
Response: Thanks a lot. The sentence has been deleted.
6) Author must reorganise this study and also it would be better if the author takes professional help for English correction.
Response: Thanks a lot. The paper has been revised.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
This manuscript contains the interesting matter. I recommend the publication after some modifications as following.
- Line 53: Indicate the specific value of LT.
- Line 59: What is unit of 20X10?
- Line 99: Fig.4 -> Fig. 4
Author Response
This manuscript contains the interesting matter. I recommend the publication after some modifications as following.
Line 53: Indicate the specific value of LT.
Line 59: What is unit of 20X10?
Line 99: Fig.4 -> Fig. 4
Response: Thanks a lot for your kind comments. The modification has been done in the manuscript.
Round 2
Reviewer 2 Report
The author has tried to improve the technical aspect of the paper but the English language is appalling.
1) In introduction section- line 29 the use of the word more and more in not right, and the better words could be there are increasing demands for ..... instead of like word such as should be used.
2) Line 31- knee implant metals that include. A new sentence should start after the word implant and can be addressed like ( Materials that are of interest for this application are 316L ....
3) Line 35. it's not right to start the sentence with word because. Because is used for giving the reason for the previous sentences.
4) line 37. instead of therefore, the word should be hence;
5) Line 41- grain refinement on.. not in
6) Line 65 - sample was putted ( its put put put and not putted) ... sample was placed
Professional English correction should be carried out to improve this manuscript before acceptance. In the present form, it's very hard to follow or understand this manuscript.
Author Response
The author has tried to improve the technical aspect of the paper but the English language is appalling.
1) In introduction section- line 29 the use of the word more and more in not right, and the better words could be there are increasing demands for ..... instead of like word such as should be used.
2) Line 31- knee implant metals that include. A new sentence should start after the word implant and can be addressed like ( Materials that are of interest for this application are 316L ....
3) Line 35. it's not right to start the sentence with word because. Because is used for giving the reason for the previous sentences.
4) line 37. instead of therefore, the word should be hence;
5) Line 41- grain refinement on.. not in
6) Line 65 - sample was putted ( its put put put and not putted) ... sample was placed
Professional English correction should be carried out to improve this manuscript before acceptance. In the present form, it's very hard to follow or understand this manuscript.
Response: Thanks a lot for your kind comments. These have been revised in the manuscript with red color, as follows:
In the introduction section-line 29, we revised the sentence to "With the development of medical science and technology, there are increasing requirements for implanted materials that can replace or assist the natural organs of humans,"
In line 31, we changed the sentence into two different sentences "With the development of medical science and technology, there are increasing requirements for implanted materials that can replace or assist the natural organs of humans, like stents, heart valves, bones, skull, and knee implant metals. Materials that are of interest for this application are 316L steel, pure titanium, and nickel-titanium (NiTi) alloy. "
In line 35, we changed the sentence into "Due to the generation of wear and abrasion during the application as bone of NiTi alloy in the human body, it is necessary to replace the implanted joints within 15-20 years."
In line 37, we changed the "therefore" into "hence".
In line 41, we changed the "grain refinement in" into "grain refinement on".
In line 65, we used the "placed" instead of "put".
In line 101, we revised the sentence into "The roughness of S-3 is higher than as-received NiTi alloy, but it is lower than that of other samples with different laser nitriding parameters."
