Analysis of the Corrosive Process Originating from Electrical Arcs on Ag–Ni Contacts Based on Residual Layer Distribution

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This study examines the arc-induced degradation mechanisms of Ag-Ni (90/10) electrical contacts, using some modern characterisation techniques such as Raman spectroscopy, 3D profilometry, and contact resistance measurements, with a nice experimental setup. Some important points are as follows:

• The study focuses on only Ag-Ni (90/10) contacts with a specific geometry. Comparing contact degradation behavior of Ag-Ni (90/10) with other contact materials or with different contact geometries would enable generalization of findings and propose potential strategies for contact performance improvement.
• Please discuss how the results might affect industrial procedures (e.g., material design, suitable replacement intervals). A small paraghraph would be nice.
• Please examine how environmental factors, particularly humidity, pressure, and airborne hydrocarbons, influence the degradation of the contacts.
• The study shows that the Ag-Ni contacts weld under high current and temperature. The experimentally applied levels of current and temperature are, however, not clearly shown. Providing these details would help comparisons with other studies.
• The resistance rate equation (on p. 11) is fragmented and hard to follow.
• Figure 1 was used twice as a caption number. Also, the caption Figure 3 was not used between Figure 2 and Figure 4.

Author Response

Dear Reviewer,

 

We sincerely thank you for your careful reading of our manuscript and your constructive comments. We truly appreciate the time and effort invested in providing valuable feedback, which has helped us to improve the quality and clarity of our work.

In the following sections, we provide a detailed response to each comment. We have addressed all concerns raised by the reviewers, revised the manuscript accordingly, and highlighted the corresponding changes in the text.

 

Review:

The study focuses on only Ag-Ni (90/10) contacts with a specific geometry. Comparing contact degradation behavior of Ag-Ni (90/10) with other contact materials or with different contact geometries would enable generalization of findings and propose potential strategies for contact performance improvement.

Please discuss how the results might affect industrial procedures (e.g., material design, suitable replacement intervals). A small paraghraph would be nice.

Response:

We thank the reviewer for this suggestion. In response, we have added a paragraph (lines 407–413) noting that Ag–Ni (90/10) contacts degrade most severely around mid-life (~6000 cycles), and that monitoring surface morphology, contact resistance, and material optimization can guide maintenance and improve performance.

Review:

Please examine how environmental factors, particularly humidity, pressure, and airborne hydrocarbons, influence the degradation of the contacts.

The study shows that the Ag-Ni contacts weld under high current and temperature. The experimentally applied levels of current and temperature are, however, not clearly shown. Providing these details would help comparisons with other studies.

Response:

We thank the reviewer for raising this point. In the Methods section, we have clarified that temperature, humidity, pressure, and airborne hydrocarbons were maintained at constant levels throughout the experiments. The applied current and temperature levels are also now explicitly reported to allow comparison with other studies.

Reviewer: The resistance rate equation (on p. 11) is fragmented and hard to follow.

Response: We thank the reviewer for this observation. The resistance rate equation on page 11 has been reformatted for clarity, with all terms defined and the equation presented in a single, coherent form to improve readability.

Reviewer: Figure 1 was used twice as a caption number. Also, the caption Figure 3 was not used between Figure 2 and Figure 4.

Response: We thank the reviewer for pointing out the figure numbering issues. The figure captions have been corrected so that each figure has a unique, sequential number, ensuring Figure 1, Figure 2, Figure 3, and Figure 4 are properly ordered.

We sincerely thank the reviewers for their constructive comments and suggestions, which have helped improve the clarity and quality of this manuscript.

 

Sincerely,
Claudia Stasac,
University of Oradea

Reviewer 2 Report

Comments and Suggestions for Authors

This work focuses on studying the arc erosion mechanism by providing a cyclic analytical view under precisely controlled laboratory conditions, advancing the understanding of Ag Ni (90/10) electrical contact degradation. This method is well-organized and the simulation results are convincing. However, before its publication, further consideration of the current manuscript is needed through improvement or answering questions.

Q1: There seem to be some issues with the size and layout of the two images in the first fig.1. Although the author intended to display the characteristics of the middle part through a) and b), the selection of images is not very aesthetically pleasing. You can use the middle part separately as (a), and then display both the upper and lower parts simultaneously in (b) figure.

Q2: At the same time, there are two images in the article with titles of fig1. It is unclear whether this is due to the author's negligence or other reasons, and appropriate modifications should be made.

Q3: In addition, the different colors displayed in the 3D images of Fig6 and Fig7 do not seem to have any practical representation function, and there seems to be no difference between the text and the images. Can the author explain the meaning represented by the colors here.

Q4: At the same time, the size of the selected rectangle and the enlarged image used in the partial enlarged images of fig12, 13, and 14 are not consistent. The selected rectangle becomes approximately square after being enlarged, and the drawing here is not rigorous enough. It should be corrected.

Q5: Some images have bolded the word "figure" in the titles below them, while others have not. The author needs to unify it.

Q6: For the experimental section, it is clearly stated that the laboratory's environmental conditions (temperature, humidity) are important, but it is recommended to supplement whether these conditions have been monitored and controlled. The moisture and hydrocarbon substances in the air can significantly affect carbonaceous deposition and oxidation, so it is necessary to explain to ensure the reproducibility of the experiment.

Q7:3D morphology and Raman spectroscopy are very useful, but adding EDS (energy dispersive X-ray spectroscopy) element surface distribution map will become a huge highlight. It can visually demonstrate how Ag and Ni elements migrate and distribute in the residual layer, directly verifying the discussion about element segregation and Ni oxidation. Even if the data is included in supplementary materials, it can significantly enhance the depth of the paper.

Q8: Reference 19 seems to have some formatting errors. It is recommended to double check the spelling and formatting of the entire text and references.

Author Response

Dear Reviewer,

 

We sincerely thank you for your careful reading of our manuscript and your constructive comments. We truly appreciate the time and effort invested in providing valuable feedback, which has helped us to improve the quality and clarity of our work.

In the following sections, we provide a detailed response to each comment. We have addressed all concerns raised by the reviewers, revised the manuscript accordingly, and highlighted the corresponding changes in the text.

Q1: There seem to be some issues with the size and layout of the two images in the first fig.1. Although the author intended to display the characteristics of the middle part through a) and b), the selection of images is not very aesthetically pleasing. You can use the middle part separately as (a), and then display both the upper and lower parts simultaneously in (b) figure.

Response:

We thank the reviewer for the suggestion. Figure 1 has been updated so that (a) shows the anode, (b) shows the cathode, and (c) shows the full contact, each displayed separately for improved clarity and visual presentation.

Q2: At the same time, there are two images in the article with titles of fig1. It is unclear whether this is due to the author's negligence or other reasons, and appropriate modifications should be made.

Response: We thank the reviewer for pointing out the figure numbering issues. The figure captions have been corrected so that each figure has a unique, sequential number, ensuring Figure 1, Figure 2, Figure 3, and Figure 4 are properly ordered.

Q3: In addition, the different colors displayed in the 3D images of Fig6 and Fig7 do not seem to have any practical representation function, and there seems to be no difference between the text and the images. Can the author explain the meaning represented by the colors here.

Response:  We thank the reviewer for this observation. The colors in the original 3D images of Figures 6 and 7 were generated automatically by MATLAB during mesh processing and did not convey any specific information. In response, we have updated the figures to be colorless to avoid confusion and better reflect the data.

Q4: At the same time, the size of the selected rectangle and the enlarged image used in the partial enlarged images of fig12, 13, and 14 are not consistent. The selected rectangle becomes approximately square after being enlarged, and the drawing here is not rigorous enough. It should be corrected.

Response: We thank the reviewer for this comment. The inconsistencies in the selected rectangles and the enlarged images in Figures 12, 13, and 14 have been corrected to ensure accurate and consistent representation.

Q5: Some images have bolded the word "figure" in the titles below them, while others have not. The author needs to unify it.

Response: We thank the reviewer for pointing this out. The formatting of all figure captions has been unified so that the word “Figure” is consistently styled throughout the manuscript.

Q6: For the experimental section, it is clearly stated that the laboratory's environmental conditions (temperature, humidity) are important, but it is recommended to supplement whether these conditions have been monitored and controlled. The moisture and hydrocarbon substances in the air can significantly affect carbonaceous deposition and oxidation, so it is necessary to explain to ensure the reproducibility of the experiment.

Response: We thank the reviewer for this suggestion. The Methods section has been updated to clarify that temperature, humidity, pressure, and airborne hydrocarbons were monitored and maintained at constant levels throughout the experiments, ensuring reproducibility and consistency of the results.

Q7:3D morphology and Raman spectroscopy are very useful, but adding EDS (energy dispersive X-ray spectroscopy) element surface distribution map will become a huge highlight. It can visually demonstrate how Ag and Ni elements migrate and distribute in the residual layer, directly verifying the discussion about element segregation and Ni oxidation. Even if the data is included in supplementary materials, it can significantly enhance the depth of the paper.

Response: We sincerely thank the reviewer for this excellent suggestion. We agree that including EDS element surface distribution maps would provide valuable insights into Ag and Ni migration and directly support the discussion on element segregation and Ni oxidation. Unfortunately, due to limitations in available equipment, we are currently unable to perform this analysis. We appreciate this idea and will consider it as a potential addition in future studies to further strengthen the work.

Q8: Reference 19 seems to have some formatting errors. It is recommended to double check the spelling and formatting of the entire text and references.

Response: We thank the reviewer for pointing this out. Reference 19, as well as the spelling and formatting of all references and the main text, have been carefully checked and corrected.

We thank the reviewer for this suggestion. The manuscript has been carefully revised for clarity, and the English has been thoroughly checked and corrected to improve readability and accurately convey the research.

We sincerely thank the reviewers for their constructive comments and suggestions, which have helped improve the clarity and quality of this manuscript.

 

Sincerely,
Claudia Stasac,
University of Oradea

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents an investigation into the degradation mechanisms of Ag–Ni (90/10) electrical contacts under controlled cycling conditions. The work is well motivated, and the results are clearly structured into distinct degradation stages. The conclusions are particularly strong in highlighting future directions, which is commendable.

That said, a few clarifications and minor corrections are recommended:

-Figure 7: It appears that the surface after 9000 cycles is the roughest and most uneven. The authors should double-check their roughness calculations to ensure consistency with the observed profiles.

-Figure 9: Please clarify what the axes represent and specify their units. It is also important to state which section of the electrode this height profile corresponds to, as surface profile varies along its length according to Figure 7.

-It is not clear whether the analysis was performed on a single electrode throughout the study or multiple samples. For example, the cross-sectional image is obtained using a destructive method, suggesting that the same electrode could not have been reused afterward. A short clarification on sample handling would improve transparency.

Overall, this is a well-executed study with practical implications for contact reliability. The inclusion of future work in the conclusion is particularly appreciated, as it points to meaningful directions for advancing this research.

Author Response

Dear Reviewer,

 

We sincerely thank you for your careful reading of our manuscript and your constructive comments. We truly appreciate the time and effort invested in providing valuable feedback, which has helped us to improve the quality and clarity of our work.

In the following sections, we provide a detailed response to each comment. We have addressed all concerns raised by the reviewers, revised the manuscript accordingly, and highlighted the corresponding changes in the text.

 

Review:

-Figure 7: It appears that the surface after 9000 cycles is the roughest and most uneven. The authors should double-check their roughness calculations to ensure consistency with the observed profiles

Response:

We thank the reviewer for this observation. We have double-checked the roughness calculations, which are correct. The apparent discrepancy was due to an incorrect axis scale in Figure 7, whom appeared to exaggerate the features, which has now been corrected.

Review:

-Figure 9: Please clarify what the axes represent and specify their units. It is also important to state which section of the electrode this height profile corresponds to, as surface profile varies along its length according to Figure 7.

Response:

We thank the reviewer for this comment. The axes in Figure 9 have now been labeled with appropriate units, and the figure caption has been updated to clarify that the height profile represents the average surface profile along the electrode, accounting for variations along its length as observed in Figure 7. This clarification has also been added to the main text.

Reviewer:

-It is not clear whether the analysis was performed on a single electrode throughout the study or multiple samples. For example, the cross-sectional image is obtained using a destructive method, suggesting that the same electrode could not have been reused afterward. A short clarification on sample handling would improve transparency.

Response:  

We thank the reviewer for this comment. We clarify that the cross-sectional analysis was performed on the same electrode that was scanned for surface measurements. This has now been explicitly stated in the Methods section to ensure transparency.

We sincerely thank the reviewers for their constructive comments and suggestions, which have helped improve the clarity and quality of this manuscript.

 

Sincerely,
Claudia Stasac,
University of Oradea