查找使用阿拉丁产品的科研文献

Electrophoretic deposition of high adhesion energetic coatings (e.g., NiO-Al/Fe2O3)

Daixiong Zhang,Xinxi He,Mei Huang,Qing Xiang

Electrophoretic deposition (EPD) is a promising method for fast-preparing thermite (Al/MO x ) coatings and other energetic coatings with the advantages of simplicity, low cost, and wide adoptability for complex shapes. However, post-sintering treatment is unsuitable for enhancing the poor adhesion of electrophoretic Al/MO x coating and other energetic coatings because of the contradiction between the sintering temperature and the trigger temperature of thermite reaction. In this work, electrophoretic Al/MO x (i.e., Fe 2 O 3 ) coatings with high adhesion were designed by using other MO x nanoparticles (i.e., NiO) prepared via oil-phase synthesis (named as O-MO x ) as an outer coating. DSC curves show that the value of heat release in the electrophoretic NiO-Al/Fe 2 O 3 coating is 2568 J g −1 . The combustion test successfully confirms a violent and quick energy releasing of the designed Al/Fe 2 O 3 coating. More attractively, this strategy can also be employed to prepare many other kinds of Al/MO x coating (i.e., CuO, MoO 3 , WO 3 , Bi 2 O 3 ) or energetic coating (i.e., B/Ti) with good adhesion via EPD. In summary, this study provides a general strategy for electrophoretic preparation of Al/MO x coatings with high adhesion, excellent thermodynamic properties and electrical explosion performance, which would solve the key issue for preparing Al/MO x coatings through EPD technology.

Tuning the reactivity of Al/Fe2O3 nanoenergetic materials via an approach combining soft template self-assembly with sol–gel process process

Tianfu Zhang,Zhen Wang,Guoping Li,Yunjun Luo

A bottom-up approach combining soft template self-assembly with sol–gel process, was adopted to prepare the assembled Al/Fe 2 O 3 nanoenergetic materials, assembly-Al/Fe 2 O 3 sample. The other two unassembled Al/Fe 2 O 3 a nanoenergetic materials, sol–gel–Al/Fe 2 O 3 sample and mixing-Al/Fe 2 O 3 sample, were prepared by sol–gel method and physical mixing method respectively. The assembly process within the preparation of the assembly-Al/Fe 2 O 3 sample was analyzed through the changes in the average hydrodynamic diameters of the particles and the micelles in solution. SEM, EDS and TEM tests were performed to demonstrate a significant improvement regarding to dispersity and arrangements of the Al and Fe 2 O 3 particles in the assembled samples, compared to that of the unassembled Al/Fe 2 O 3 samples. DSC test was employed to characterize the reactivity of the samples. The heat release of the assembled Al/Fe 2 O 3 sample was 2088   J/g, about 400 and 990   J/g more than that of the sol–gel–Al/Fe 2 O 3 sample and mixing-Al/Fe 2 O 3 sample, respectively.

A comparative study of thermal kinetics and combustion performance of Al/CuO, Al/Fe2O3 and Al/MnO2 nanothermites

Jiaxing Song,Tao Guo,Miao Yao,Jialin Chen,Wen Ding,Fengli Bei,Yiming Mao,Zhongshen Yu,Junyi Huang,Xiaonan Zhang,Qin Yin,Shuo Wang

The performance of energetic materials is mainly reflected in two aspects, thermal performance and combustion performance. To figure out the differences in reaction performance, in this paper, thermal and combustion properties of Al/CuO, Al/Fe 2 O 3 and Al/MnO 2 nanothermites were studied respectively by thermal analysis and fast heating wire experiments. According to the thermal analysis, the exothermic peak temperature points of Al/MnO 2 , Al/CuO, Al/Fe 2 O 3 nanothermites were 552.1 °C, 563.1 °C and 565.3 °C, respectively, while the sequence of activation energy calculated from low to high was Al/Fe 2 O 3 , Al/CuO, Al/MnO 2 nanothermites. By the way, the values of Al/CuO and Al/Fe 2 O 3 nanothermites showed little difference in temperature and activation energy. The ignition energy characterized by direct current had little difference among them, and the sequence from low to high was Al/MnO 2 , Al/Fe 2 O 3 , Al/CuO nanothermites, corresponding to 1.169 A, 1.214 A and 1.221 A, respectively. As for burning rate, Al/CuO burnt the fastest clearly while the Al/Fe 2 O 3 burnt the longest. In terms of combustion performance, Al/CuO and Al/MnO 2 were basically the same, with little splash of sparks, and the concentrations of combustion energy were better. The combustion phenomenon of Al/Fe 2 O 3 nanothermite was quite unique with a large number of scattered sparks and poor energy concentration. Finally, the intrinsic reasons for above different phenomena of these three nanothermites were analyzed and discussed.

Electrophoretic deposition and characterization of nano-Al/Fe2O3 thermites

Daixiong Zhang,Xueming Li,Bo Qin,Chuan Lai,Xiaogang Guo

Nano-Al/Fe 2 O 3 thermites were successfully prepared as film by a novel electrophoretic deposition (EPD) method. The micromorphology investigations demonstrate that electrophoretic deposition of nano-Al/Fe 2 O 3 thermites offer a feasible route for the formation of the interfacial contact between nano-Al and nano-Fe 2 O 3 particles in the film is nanoscaled. Linear relationship studies showed that a coefficient of proportionality between mass ratio in deposited films and that in suspension was observed for EPD of nano-Al/Fe 2 O 3 thermite. The optimum velocity in combustion investigations was found to correspond to mass ratio in deposited thermite. The EPD method is promising for preparation of nano-Al/Fe 2 O 3 thermite with excellent combustion performance.

Microstructured Al/Fe2O3/Nitrocellulose Energetic Fibers Realized by Electrospinning

Rui Li,Hongmei Xu,Hailong Hu,Guangcheng Yang,Jun Wang,Jinpeng Shen

Preparation and characterization of the Al/Fe2O3/RDX/NC nanocomposites by electrospray

Yang Hongtao,Liu Yunfei,Huang Haitao,Zhao Yu,Song Kuanguang,Wang Haiyang,Xie Wuxi,Cheng Yi,Fan Xuezhong

In this study, an advanced electrospray process was successfully used to fabricate aluminum nanopowders (Al)/iron oxide nanopowders (Fe 2 O 3 )/hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)/nitrocellulose (NC) composite materials containing different RDX contents. Differential scanning calorimetric analysis indicates that the decomposition temperature of the RDX in the composition prepared by electrospray has a decrease of about 20 °C compared with the raw RDX. Combustion performances in air show that the RDX decreases combustion performance of nanothermites, and the combustion intensity decreases as the RDX content increases. Furthermore, the combustion cell test indicates that the maximum pressure peak has been greatly improved for the Al/Fe 2 O 3 /RDX/NC composites. The amount of released gas can be adjusted by the RDX content in Al/Fe 2 O 3 /RDX/NC composite.

Electrophoretic Deposition of Superhydrophobic Al/Fe2O3 Nanothermite with Long–Term Storage Stability

Haibing Zhang,Haitao Wu,Peng Xu,Zidong Li,Wuyang Zhang,Huixian Huang,Qing Zhou,Xingui Yue,Jiankang Bao,Xueming Li

In this study, a superhydrophobic Al/Fe 2 O 3 nanothermite with long–term storage stability was prepared by electrophoretic deposition of nano–Al particles and nano– Fe 2 O 3 microboxes on Ti substrate and subsequent modification process. The composition and morphology of Al/ Fe 2 O 3 nanothermite were systematically characterised through X–ray diffraction and scanning electron microscope. In addition, the water contact angle measurements and the immersion test demonstrated the excellent superhydrophobic properties of the as–prepared Al/ Fe 2 O 3 nanothermite. 10 days after underwater immersion, the heat release of the superhydrophobic Al/ Fe 2 O 3 nanothermite remained 982.7 J/g, which was higher than 514.6 J/g of the sample without superhydrophobic treatment. This work provides a beneficial sight for enhancing the long–term storage stability of nanothermite in practical application.

Exploring the solid-state interfacial reaction of Al/Fe2O3 nanothermites by thermal analysis

Zhou Xiang,Zhu Ying,Ke Xiang,Zhang Kaili

In this study, we use simultaneous differential scanning calorimetry and thermogravimetric analysis to analyze the solid-state reaction characteristics of Al/Fe 2 O 3 nanothermites before n -Al melts. Different experimental setups for thermal analysis are compared, and the heat-release characteristics are studied on Al/Fe 2 O 3 nanothermites in the form of powder and pellet, respectively. It is found that protection provided by mere argon flow is far from enough for thermal analysis of Al/Fe 2 O 3 nanothermites. The experimental setup must be free of oxygen; otherwise, the determined exothermic peak is mostly the oxidation of n -Al by the residue oxygen molecules in the furnace body, due to the high reactivity and moderate accessibility of free oxygen molecules. Under proper experimental setup, it is found that besides the redox reaction between n -Al and n -Fe 2 O 3 , intermetallic reaction also occurs to form Fe 4 Al 13 . Moreover, the intermetallic reaction is more noticeable for nanothermite pellet than for nanothermite powder, and the eutectic reaction of Fe 4 Al 13 and n -Al leads to melting peaks below 655 °C. The results indicate that instrument configuration and sample status affect the testing results to a large extent, and one should be prudent to derive reaction characteristics of nanothermites.

Environment-Friendly Formation of High Energetic Nano-Al/Fe2O3 Bilayer by Aqueous Electrophoretic Deposition

Daixiong Zhang,Rui Pei,Xiofei Peng,Qing Xiang,Xia Wang

In this study, nano-Al/Fe 2 O 3 bilayer was successfully formed via aqueous electrophoretic deposition (EPD) route for the first time. For this formation, the first layer of nano-Fe 2 O 3 was prepared by EPD using the bi-additive of 0.015 mM HCl+10 mg L −1 PEI, and then the second layer of nano-Al was immediately prepared by EPD using 5 mg L −1 PEI as additive. The electrophoretic nano-Al/Fe 2 O 3 bilayer had high heat release of ∼2800 J g −1 and exhibited good combustion performance. In comparison with the previous work realized by using organic-solvent-EPD, we believe this study can pave a new way for preparing the bilayers of nanothermites or metallic reactive materials by more cost-effective and environment-friendly aqueous EPD route.

Effects of hollow carbon nanospheres on combustion performance of Al/Fe2O3-based nanothermite sticks

Haifeng Yang,Chuanhao Xu,Shuaishuai Man,Hebin Bao,Yuting Xie,Xiaodong Li,Guangcheng Yang,Zhiqiang Qiao,Xueming Li

Effects of hollow carbon nanospheres on the combustion behavior of Al/Fe 2 O 3 -based thermite sticks are studied in this work. The results from laser ignition experiments confirm that the presence of hollow carbon nanospheres not only can reduce the ignition threshold because of the excellent laser energy absorption capacity, but also play a positive role in heightening the heat transfer efficiency by introducing pores and increasing heat-flow output during the combustion process. The video snapshots indicate that the combustion propagation stages, including ignition, acceleration, and steady combustion, all improved significantly with the suitable inclusion of hollow carbon nanospheres. The modified composites containing 4 wt% hollow carbon nanospheres exhibit a minimum ignition threshold (28 mJ), shorter acceleration duration (76 ms), higher combustion rate (10.10 cm/s) and steady combustion temperature (~2850 K). Furthermore, it exhibits a remarkable enhancement in energy release (537.36 J/g) and pressure output (0.91 Mpa), which are 1.67 and 1.34 times than that of pristine thermite sticks, respectively. Overall, this work demonstrates that the high porosity structure and heat-flow release of thermite sticks facilitate convective heat transfer and eventually improve the combustion behavior, which can provide some reference in the design and optimization of microstructure and composition in micro-energetic devices.

Study on combustion characteristics and pyrotechnic cutting effects of bimetal thermite Ni/Al/Fe2O3 system

Mi Li,Zhongxuan Han,Lin Jiang,Guozhong Xu

Nano-thermite has become a subject of significant interest in the composite energetic materials field due to its high energy release rate. To cater to diverse engineering needs, thermite formulations are often customized to fulfill specific criteria. This study investigates the potential of metal nickel (Ni) as an additive to modify nano-thermite formulations, selected for its optimal calorific values and chemical reactivity. The base materials, nano-aluminum (Al) and iron oxide (Fe 2 O 3 ), are blended with varying mass ratios of Ni (1 %, 3 %, 5 %, 7 %, 9 %) using the wet ball milling method. Pre-reaction and post-reaction morphological and compositional alterations in the resultant thermite samples are scrutinized through SEM and XRD characterization tests. Moreover, DSC analysis and combustion experiments were conducted to examine the pyrolysis and combustion behaviors of the evaluated samples. The results reveal a reduced exothermic peak on the DSC curves with the introduction of Ni, making the liquid-solid ( L - S ) phase reaction more challenging compared to the Al/Fe 2 O 3 thermite. Intriguingly, Ni addition progressively decreases the combustion temperature of thermites as the Ni's mass ratio increases, with a peak efficiency at 7 % in the perforation tests on stainless-steel plates. This research further reveals that the thermite reaction mechanism is a combined consequence of the “pre-ignition-fusion” and “fusion-diffusion” mechanisms. These insights can provide valuable guidance for designing thermite formulations for potential applications in storage, management, and pyrotechnic cutting areas.

Combustion/decomposition characteristics of 3D-printed Al/CuO, Al/Fe2O3, Al/Bi2O3 and Al/PTFE hollow filaments

Lin Zhong,Xu Zhou,Xinying Huang,Dawei Zheng,Yaofeng Mao,Ruihao Wang,Dunju Wang

In recent decades, the preparation of various metastable intermolecular composites (MICs) has been widely reported in pursuit of excellent reactivity and safety. However, there is still relatively little research on structural energetic materials (EMs) through 3D printing of MICs inks. In this work, the hollow filaments with different MICs formulas were prepared by 3D printing using a core-shell nozzle. The morphology, thermal decomposition and gas-generation performance of the filaments were characterized, and the different combustion stages of the filaments were analyzed. The results show that the hollow filaments exhibit shorter unsteady combustion time and significantly increased steady flame propagation rate compared with solid filaments. For the hollow filaments of Al/CuO/F2311 formula (15 wt % of F2311), the unsteady combustion time is as low as 0.65 ms, and the steady flame propagation rate reaches 206.936 g/s. Thermal analysis and constant-volume combustion tests show that Al/CuO/F2311 formula provides the lowest thermal decomposition onset temperature (288 °C) and the best gas-generation performance (peak pressure: 0.191 MPa, pressurization rate: 12.337 MPa/s) compared with other composites.