{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,3]],"date-time":"2026-07-03T05:16:34Z","timestamp":1783055794118,"version":"3.54.6"},"reference-count":18,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2026,6,23]],"date-time":"2026-06-23T00:00:00Z","timestamp":1782172800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>Copper azides are promising energetic materials for miniaturized pyrotechnic devices and micro explosive trains owing to their short detonation growth distance and high initiation energy. However, controllable preparation of copper nanoparticle precursors and their in situ conversion to copper azides under mild conditions remains challenging. In this study, copper nanoparticles were synthesized via a coordination-assisted aqueous reduction method at room temperature under air atmosphere using nitrilotriacetic acid disodium salt (NTA\u00b7H\u00b72Na) as the complexing agent. The resulting nanoparticles were pressed into polyester rings to construct confined precursor structures, and copper azide micro-charges were prepared through in situ gas\u2013solid reaction with HN3 gas generated from NaN3 and concentrated phosphoric acid at 60 \u00b0C. SEM characterization revealed that the morphological evolution of copper azides followed a three-stage pattern: \u201cproduct island nucleation, branch\/block coalescence growth, and continuous product layer formation and structural reconstruction\u201d. Detonation velocity tests using the electrical probe method showed an average value of (5.10 \u00b1 0.07) \u00d7 103 m\/s. Flyer impact initiation tests demonstrated that, with a charge thickness of 1.00 mm, both a 30 \u03bcm polyimide flyer and a 40 \u03bcm titanium flyer could successfully initiate a HNS\u2013IV explosive. The preparation methodology and performance characterization established in this work provide an experimental basis for the application of copper azides in micro-initiation systems.<\/jats:p>","DOI":"10.3390\/mi17070763","type":"journal-article","created":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T05:52:11Z","timestamp":1782453131000},"page":"763","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Room-Temperature Aqueous Synthesis of Copper Nanoparticles and Their In Situ Conversion to Copper Azides"],"prefix":"10.3390","volume":"17","author":[{"given":"Chang","family":"Leng","sequence":"first","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mingyu","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qingxuan","family":"Zeng","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pengfei","family":"Xue","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jie","family":"Ren","sequence":"additional","affiliation":[{"name":"China Research and Development Academy of Machinery Equipment, Beijing 100089, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhenhao","family":"Shi","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu","family":"Zhou","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhongcai","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Explosion Science and Safety Protection, School of Mechatronical Engineering, Beijing Institute of Technology, Beijing 100081, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,23]]},"reference":[{"key":"ref_1","first-page":"606","article-title":"Review on Micro Fire-train based on Flyer Impact Initiation","volume":"31","author":"Liu","year":"2023","journal-title":"Chin. 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