Gap initiation with 20.35 mm: an initiator integrating the Al/CuOx multilayer film and traditional electronic plug to enhance the ignition ability

In order to enhance the ignition ability and reliability of traditional electronic initiators, a novel electronic initiator has been designed to integrate with a nanothermite multilayer film and an electrode plug. The Al/CuOx nanothermite multilayer film with different thickness is deposited on the surface of the electrode plug by magnetron sputtering which uses Pt–W wire as electronic resistance. The exothermicity of Al/CuOx nanothermite multilayer film is so favourable that the ignition ability of electronic initiator is significantly improved. The full firing-voltage sensitivity of the electronic initiator is 10.8 V. The thickness of Al/CuOx multilayer film has negligible effects on the ignition time and ignition energy, but leads to great impacts on the function time, the maximum length of combustion flame and ignition ability. The electrical ignition experiments have exhibited outstanding ignition ability, since the electronic initiator can easily fire the insensitive ignition composition of boron-potassium nitrate (B-KNO3) tablet in a gap of 20.35 mm. It proves that this novel proposal of remoulding the traditional electronic ignition devices will distinctly improve the ignition ability and reliability of electronic initiator.


07-Feb-2019
Dear Dr Ni, The editors assigned to your paper ("Gap initiation with 20.35 mm: an initiator integrating the Al/CuOx multilayer film and traditional electronic plug to enhance the ignition ability") have now received comments from reviewers. We would like you to revise your paper in accordance with the referee and Associate Editor suggestions which can be found below (not including confidential reports to the Editor). Please note this decision does not guarantee eventual acceptance.
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• Authors' contributions All submissions, other than those with a single author, must include an Authors' Contributions section which individually lists the specific contribution of each author. The list of Authors should meet all of the following criteria; 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it critically for important intellectual content; and 3) final approval of the version to be published.
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Kind regards, Royal Society Open Science Editorial Office Royal Society Open Science openscience@royalsociety.org on behalf of Professor R. Kerry Rowe (Subject Editor) openscience@royalsociety.org Associate Editor's comments: Thank you for the submission to Royal Society Open Science. We have now received two reviewers' reports on your paper. Given the numerous concerns of referee 2, we require you to complete a revision of your paper that addresses these before we can consider the paper further for publication. You should incorporate their recommendations in full or provide a scientifically valid rebuttal of those concerns in your revision --if you do not do so, and your changes or responses do not satisfy the reviewer, you may not receive a second opportunity to address these concerns. Furthermore, the more critical reviewer indicates the manuscript has substantial linguistic errors. Please ensure that you utilise a language polishing service (for instance https://royalsociety.org/journals/authors/language-polishing/) before resubmitting, and ensure that you include evidence of their support in your revision --if you do not do so, the paper will be returned to you. Good luck! Comments to Author: Reviewers' Comments to Author: Reviewer: 1 Comments to the Author(s) The author have presented an interesting work on multilayer film of Al/Cux synthesized by a classical route. The work is plausible and useful. However, the major problem to me is the language really needs to be polished, with the following point to be considered: 1. replace the full stop with comma after plug in the second line in abstract; 2. page 2, line 4 in the second paragraph, double check Al/Ni, it might be Al/NiO; 3. page 5 line 7, replace weekly with weak; 4. page 5 line 16, the statement on thickness effect is incorrect; 5. page 6, line 4, replace was with were; a lot of grammar errors in this paragraph and beyond; Reviewer: 2 Comments to the Author(s) Review Report for RSOS-181686 General Comments: This manuscript reported on the preparation and performance characterization of an electronic initiator which is based on nanothermite multilayer film and electrode plug. The ignition ability of electronic initiator with different thickness of energetic film was investigated and proved to be with an improved safety and reliability. The idea of integrating nanothermite multilayer film and electrode plug directly is interesting, simple and easy to implement. However, the reviewer has some concerns as stated in specific comments. These issues should be clarified before the manuscript could be considered for publication.
Specific Comments: 1. Section 3, the total thickness of nanothermite film was demonstrated to have little effect on heat release on page 5. However, page 9, authors stated the "heat output distinctly increased as the thickness raising", which seems to be a contradiction. Please explain. Besides, most papers show that the factor that affects the exothermic performance of multilayer energetic materials is the modulation period. But here, much better ignition ability in the gap test can be achieved by simply increasing the thickness of film. What's the possible mechanism? It would be better to add more in-depth discussion. 2. Introduction part, the authors used SCB as a comparative example. However, most of the cited references have no relation with SCB, e.g.  Figure 1, is it possible to add magnified figures of one electrode plug with and without nanothermite multilayer film, especially the area between electrodes, to see some details? 4. Section 2.2, the authors set the single layer thickness of Al film and CuO film were 100 nm and 200 nm, but in Figure 2a, the two layers seem not to be twice in thickness. Figure 2b, why is there no obvious layering in EDS mapping? In addition, there are several unlabeled peaks in EDS plot. 6. Page 5, it seems the exothermic reaction after Al melting (660 C) contributes to heat release as well. Hence, the statement that "heat output was caused by solid-solid reaction" is not appropriate here. 7. Page 5, last sentence, the Figure SI 2 is voltage-current curve instead of DSC plots. Please check. 8. Page 6, the described Cu peaks (43.29, 50.43 and 74,13 degree) are not that obvious in the product curve of Figure 4. Besides, what do the sharp peaks in the product curve at around 53 and 55 degree stand for? 9. Page 7, please define function time. Because from Figure 6, the flame root of the 8 μm-thick sample was extinguished earlier than that of 4.58 μm-thick sample. 10. In order to highlight the advantages of Al/CuOX film, it is suggested to add the high-speed camera ignition images of traditional electronic plug (optional). 11. Page 9, "Although three kinds of initiators can easily fire the B-KNO3 tablet when it was intimately contacted with film, the ignition ability was much more differently." The authors did not provide related experimental data to support this sentence. 12. Page 9, last sentence, what does the "same condition" mean? Same contact or same gap distance? 13. Why the authors think the Al/CuOx layer can improve the safety of initiator? From this manuscript, the Al/ CuOx layer decreased the ignition voltage and it is possible to ignite even the gap increased to over 20mm. Doesn't it mean the initiator is less safe? 14. Two related papers should be included in the references:

Are the interpretations and conclusions justified by the results? Yes
Is the language acceptable? Yes

Recommendation?
Accept as is

Comments to the Author(s)
The revision has addressed all points well.

Review form: Reviewer 2
Is the manuscript scientifically sound in its present form? Yes

Do you have any ethical concerns with this paper? No
Have you any concerns about statistical analyses in this paper? No

Recommendation?
Accept with minor revision (please list in comments)

Comments to the Author(s)
Review Report for RSOS-181686.R1 General Comments: The revised manuscript has been significantly improved, especially the introduction part. It can be considered for publication after the following minor issues being modified.
Specific Comments: 1. Please correctly mark the labels in Figure 1 and 7. 2. Page 6, is it better to move XRD result forward since there's no data from product? 3. Page 7, the authors are not sure about "the product Cu" according to last version of manuscript, and there's no evidence to prove Cu was eventually produced. 4. Please check the title of Figure SI 3.

01-Apr-2019
Dear Dr Ni: On behalf of the Editors, I am pleased to inform you that your Manuscript RSOS-181686.R1 entitled "Gap initiation with 20.35 mm: an initiator integrating the Al/CuOx multilayer film and traditional electronic plug to enhance the ignition ability" has been accepted for publication in Royal Society Open Science subject to minor revision in accordance with the referee suggestions. Please find the referees' comments at the end of this email.
The reviewers and Subject Editor have recommended publication, but also suggest some minor revisions to your manuscript. Therefore, I invite you to respond to the comments and revise your manuscript.
• Ethics statement If your study uses humans or animals please include details of the ethical approval received, including the name of the committee that granted approval. For human studies please also detail whether informed consent was obtained. For field studies on animals please include details of all permissions, licences and/or approvals granted to carry out the fieldwork.
• Data accessibility It is a condition of publication that all supporting data are made available either as supplementary information or preferably in a suitable permanent repository. The data accessibility section should state where the article's supporting data can be accessed. This section should also include details, where possible of where to access other relevant research materials such as statistical tools, protocols, software etc can be accessed. If the data has been deposited in an external repository this section should list the database, accession number and link to the DOI for all data from the article that has been made publicly available. Data sets that have been deposited in an external repository and have a DOI should also be appropriately cited in the manuscript and included in the reference list.
If you wish to submit your supporting data or code to Dryad (http://datadryad.org/), or modify your current submission to dryad, please use the following link: http://datadryad.org/submit?journalID=RSOS&manu=RSOS-181686.R1 • Competing interests Please declare any financial or non-financial competing interests, or state that you have no competing interests.
• Authors' contributions All submissions, other than those with a single author, must include an Authors' Contributions section which individually lists the specific contribution of each author. The list of Authors should meet all of the following criteria; 1) substantial contributions to conception and design, or acquisition of data, or analysis and interpretation of data; 2) drafting the article or revising it critically for important intellectual content; and 3) final approval of the version to be published.
All contributors who do not meet all of these criteria should be included in the acknowledgements.
We suggest the following format: AB carried out the molecular lab work, participated in data analysis, carried out sequence alignments, participated in the design of the study and drafted the manuscript; CD carried out the statistical analyses; EF collected field data; GH conceived of the study, designed the study, coordinated the study and helped draft the manuscript. All authors gave final approval for publication.
• Acknowledgements Please acknowledge anyone who contributed to the study but did not meet the authorship criteria.
• Funding statement Please list the source of funding for each author.
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Once again, thank you for submitting your manuscript to Royal Society Open Science and I look forward to receiving your revision. If you have any questions at all, please do not hesitate to get in touch. The revised manuscript has been significantly improved, especially the introduction part. It can be considered for publication after the following minor issues being modified.
Specific Comments: 1. Please correctly mark the labels in Figure 1 and 7. 2. Page 6, is it better to move XRD result forward since there's no data from product? 3. Page 7, the authors are not sure about "the product Cu" according to last version of manuscript, and there's no evidence to prove Cu was eventually produced. 4. Please check the title of Figure

05-Apr-2019
Dear Dr Ni, I am pleased to inform you that your manuscript entitled "Gap initiation with 20.35 mm: an initiator integrating the Al/CuOx multilayer film and traditional electronic plug to enhance the ignition ability" is now accepted for publication in Royal Society Open Science.
You can expect to receive a proof of your article in the near future. Please contact the editorial office (openscience_proofs@royalsociety.org and openscience@royalsociety.org) to let us know if you are likely to be away from e-mail contact. Due to rapid publication and an extremely tight schedule, if comments are not received, your paper may experience a delay in publication.
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Dear Editors and Reviewers,
Thank you for your letter and for the reviewers'comments concerning our manuscript entitled "Gap initiation with 20.35 mm: an initiator integrating the Al/CuOx multilayer film and traditional electronic plug to enhance the ignition ability" (ID RSOS-18168). Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. The main corrections in the paper and the responds to the reviewer's comments are as following. Thanks for all the help. Best wishes Debin Ni Reviewer: 1 1. replace the full stop with comma after plug in the second line in abstract; Response: The sentence was revised.
2. page 2, line 4 in the second paragraph, double check Al/Ni, it might be Al/NiO; Response: It should be Al/NiO, and Al/Ni was deleted.
3. page 5 line 7, replace weekly with weak; Response: The sentence of "and the low temperature weak exothermic peak was not expected to play a main role in the ignition process" was revised. The word of "weakly" was introduced to page 5 line 7, "One weakly exothermic peak" 4. page 5 line 16, the statement on thickness effect is incorrect; Response: As we known, the modulation period and modulation ratio will influence the heat release of nanothermite film. In this paper, three kinds of Al/CuOx multilayer film were the same modulation period and modulation ratio, the only difference was thickness. The heat release measured from DSC was the amount of heat of unit mass, it was no related to the thickness. In addition, the results of DSC were calculated by software, but the integral area of heat release was chosen manually, so the result will be different. So, we think that the thickness of film has little effect on heat release. 5. page 6, line 4, replace was with were; a lot of grammar errors in this paragraph and beyond; Response: The grammar in this paragraph was double checked. And the English grammar, sentence patterns and phrases of entire manuscript sentences were carefully checked.