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Article

Ignition and Combustion Characteristics of B/NC/CuO Thermite Microparticles

by
Jie Wang
1,
Hongtao Yang
2,
Long Cheng
1,
Pin Gao
3,
Yanchun Li
1 and
Dongming Song
1,*
1
School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China
2
Department, Xi’an Modern Chemistry Research Institute, Xi’an 710065, China
3
Chemical Materials Testing Center, Nanjing University of Science and Technology, Nanjing 210094, China
*
Author to whom correspondence should be addressed.
Metals 2022, 12(9), 1419; https://doi.org/10.3390/met12091419
Submission received: 5 July 2022 / Revised: 22 August 2022 / Accepted: 26 August 2022 / Published: 27 August 2022
(This article belongs to the Special Issue Advanced Nano Metallic Fuels Used in Energetic Materials)
Browse Figures
Versions Notes

Abstract

:
To improve the combustion stability and ignition performance of thermite, B/NC/CuO micro particles were prepared from boron (B), nano copper oxide (CuO), and nitrocellulose (NC) as an energetic binder through the electrospray technique. The burning rate dependency on boron content, ambient temperature, and pressure was estimated by compressing B/NC/CuO micro particles into columns. Scanning electron microscopy results show that the sizes of these particles mostly lie in the range of 3–4 μm. The particles are ignitable and burn consistently with minor variations in the conditions: B content (8.3–17%), ambient temperature (−50–55 °C), and ambient pressure (0.02–0.1 MPa). The optimum formula was observed for micro particles with 11 wt% B content. Compared with the ball milling sample, the standard deviation of the burning rate of the electrosprayed sample was reduced by 32%. Combustion is barely affected by ambient pressure. Between −50 °C to 55 °C, the burning rate of B/NC/CuO increases by 14.16% from an initial rate of 13.35 mm⋅s−1. In addition, the laser ignition energy required for B/NC/CuO microparticles was also reduced from 70 to 45 mJ.

1. Introduction

Thermite is a mixture of metal and metal oxide or non-metal oxide, which can release a lot of heat upon ignition [1]. Therefore, they have been widely used for various applications, such as explosions, pyrotechnics, and micro-actuators [2,3,4]. The main studies about thermites have focused on aluminum (Al)-based thermite [5,6,7], e.g., Al/CuO, Al/Fe2O3, etc. In comparison to Al, boron (B) has higher volumetric and gravimetric calorific values [8]. However, applications of B-based thermites are limited due to their high ignition temperature and low combustion efficiency, making the combustion of thermites difficult [9,10,11]. Recently, to overcome these challenges of B, different metal oxides have been chosen to enhance the combustion performance of B [12]. Liu et al. reported that the reaction temperatures of nano-B/NiO [13] and nano-B/CuO [14] particles were 30 °C and 116.86 °C lower than that of B particles, respectively. Xi et al. studied the influence of varieties of metal oxides (MgO, Al2O3, Bi2O3, Fe2O3, etc.) by adding them to B particles [15], and the results revealed that Bi2O3 can decrease the ignition temperature by 15.2%. Wang et al. [16] studied the combustion performance of B/Bi2O3 by rapid heating (>105 K/s) temperature-jump/time-of-flight mass spectroscopy, which indicated that B/Bi2O3 can be ignited at a temperature as low as 520 °C. However, the disadvantages of Bi2O3, such as high electrostatic sensitivity or low ignition thresholds [17], pose a hidden threat during the processes of transportation and storage.
In addition, the combustion performance of thermites can also be improved by adopting appropriate preparation procedures, including ultrasonic mixing [18] and arrested reactive milling [19]. However, boron particles are easily agglomerated owing to their larger specific surface area and denser structure. This suggests that traditional physical mixing methods are not effective enough to mix the particles homogeneously, which will result in inconstant combustion [20,21]. The electrospray method is a technique of atomization of a liquid solution into small droplets, and subsequently the solvent of the liquid drop evaporates during the flying process, forming dry particles, fibers, or films [22,23]. Due to its low cost and simple operation, it has already been employed extensively in the fabrication of nano-energetic composites [24,25]. The size and morphology of the particles can be easily tuned by changing the binder content, spray speed, voltage, and distance between the nozzle and substrate [26]. Haiyang Wang [27] prepared particles of nano energetic materials with highly uniform particle sizes via the electrospray technique. The results showed that nanoparticles had excellent combustion performance, which indicates that electrosprays could enhance combustion characteristics by improving the morphology and dispersion of the sample. External environmental parameters, such as ambient temperatures and pressure, are important factors in the combustion performance of these thermites.
Herein, the electrospray method was employed to prepare B/NC/CuO thermites, where the CuO nanoparticles were applied to promote a continuous exothermic thermite reaction to reduce the reaction temperature [28]. Nitrocellulose (NC), an energetic binder with a low decomposition temperature, was used to bind the micro-B and nano-CuO together. The morphology of the B/NC/CuO thermite was characterized by SEM. Furthermore, the influence of B content, temperature, and pressure on the combustion performance of thermite was also investigated. The laser ignition energy and combustion process of the B/NC/CuO thermite were recorded by CO2 laser igniter and high-speed photography, respectively. The reaction characteristics of the thermite were evaluated based on the DSC results.

2. Experimental Section

2.1. Materials

Boron powder (B, amorphous, 1–2 μm, ≥96%) used was produced by Liaobin Chemical Co., Ltd., (Yingkou, China). Copper oxide (CuO, 50 nm, ≥99.5%) was purchased from Aladdin (Shanghai, China). Nitrocellulose (NC, 1000 polymerization degree, 11.9% nitrogenous content) was generously donated by Qing’an Chemical Co. Ltd. (Dalian, China). Ethanol (C2H6O, ≥99.8%) and diethyl ether (C4H10O, ≥99.8%) were purchased from Sinopharm (Shanghai, China).

2.2. Physical Ball Milling of B/NC/CuO Thermite

NC was weighed (according to the mass percent of each component in Table 1) and fully dissolved in a solution of ethanol (20 mL) and diethyl ether (20 mL) solvents. Boron powder and CuO powder were weighed and added to a planetary ball mill (ND7-4L, Nanjing Nanda Tianzun, Nanjing, China). Then 40 mL of NC solution was poured into the mill and ground at 300 r·min−1 for 30 min with 30 agate balls (2/3 of 5 mm balls and 1/3 of 15 mm balls). Finally, the obtained products were centrifuged (TGL-10B, Shanghai Anting, Shanghai, China) and vacuum-dried at 60 °C for 12 h.

2.3. Electrospray of B/NC/CuO Thermite

The electrospray technique for the preparation of B/NC/CuO thermite is illustrated in Figure 1.
NC was weighed (Table 1) and completely dissolved in a mixture of solvents, ethanol (4 mL), and diethyl ether (4 mL). Amorphous B and CuO were dispersed into the NC solution and then ultra-sonicated (500 W, 40 kHz for 1 h) to prevent aggregation. The resulting solution was stirred for 24 h to form a stable suspension. Lately, the prepared suspension was filled into a syringe, and ejected through a metal nozzle (inner diameter is 0.51 mm, outer diameter is 0.80 mm) at a flow rate of 1.5 mL·h−1 with the help of a syringe pump (RSP01-B, RISTRON, Jiaxing, China). The metal nozzle was connected to the positive electrode of a high-voltage power supply (0–30 kV, TE4020, TESLAMAN, Dalian, China) with a working voltage of 16, 18, and 20 kV. An aluminum foil (fixed on a non-conductive plastic plate and grounded) was used as a substrate. The distance between the metal nozzle and the aluminum substrate was adjusted to 10 cm. Upon applying a voltage to the metal nozzle, a high-voltage electrostatic field was formed between the nozzle and the aluminum substrate. Finally, the suspension was atomized to form micro-droplets under the action of the electrostatic field and surface tension. As the droplets moved toward the receiver, the solvent was continuously volatilized, and finally, the B/NC/CuO composites were collected on the aluminum substrate.

2.4. Preparation of B/NC/CuO Thermite Device

To characterize the combustion performance of B/NC/CuO thermite, 150 mg samples were pressed into iron tubes (ϕ7 mm, 14 mm) under a pressure of 4 MPa, as depicted in Figure 2.

2.5. Characterization of B/NC/CuO Thermite

2.5.1. Surface Morphology

The electrosprayed and ball-milled B(11%)/NC/CuO thermite were made to adhere to gold plating (SCD500, Leica EM, Germany) to increase the conductivity of the samples. The morphology of the thermites was characterized by scanning electron microscopy (SEM, S-4800, Hitachi, Tokyo, Japan) at 15 kV.

2.5.2. Combustion Performance of B/NC/CuO Thermite

The iron tube filled with thermite was fixed in an aluminum chamber, connected with a DC power (4 A, 30 ms) using an electric fuse (coated with Si/Pb3O4 igniter), and covered with a plasticized glass cover. A high-speed camera connected to the oscilloscope was placed above the glass cover (WaveSurfer 44Xs, LeCroy, America). The vacuum pump was opened for vacuuming after fixing the device. As the pressure gauge displayed the required pressure value, the valve of the vacuum pump was closed. The oscilloscope and DC power were opened for immediate igniting, and the data were recorded. The experimental setup is shown in Figure 3.
The burn rate (R) was defined as the total length (L) of the samples divided by the total time (t) necessary for the flame to propagate through the sample. This was calculated using the equation given below [29]. Three measurements were carried out for each sample.
R= L/t

2.5.3. Laser Ignition Energy of B/NC/CuO Thermite

The minimal laser ignition energy of the B/NC/CuO thermite was measured using a CO2 laser igniter. 20 mg of the samples were weighed, filled into copper primer caps of diameter 5.5 mm, and ignited in air. The CO2 laser beam with a ZnSe lens was focused on 250 μm diameter, the pulse width was set at 50 ms, and the laser power range was 1–8 W. Five measurements were carried out for each laser energy determination. The combustion process of the samples was monitored by a high-speed camera at 5000 frames per second.

2.5.4. Thermal Performance

The thermal properties of B/NC/CuO thermite were investigated using DSC (NETZSCH, STA449C, Germany). 1–2 mg of the samples was placed in an Al2O3 (85 μL) crucible with a 1 mm hole on the lid. The sample was heated in an N2 (20 mL·min−1) atmosphere from 30 to 1000 °C at a heating rate of 10 K⋅min−1.

3. Results and Discussion

3.1. Morphology of B/NC/CuO

The SEM images of B/NC/CuO powders prepared by the electrospray and ball-milling methods are shown in Figure 4. The morphology of ball-milled B/NC/CuO particles (Figure 4g,h) is irregular, with a small number of lumps (the part circled in red). However, electrosprayed materials (Figure 4a–f) exhibited a spherical morphology with uniform dispersion (refer to the part of red circle). Compared with the voltages at 16 kV (Figure 4a,b) and 20 kV (Figure 4e,f), the particle size of the samples prepared at 18 kV (Figure 4c,d) was evenly distributed between 3–4 µm, and there was almost no agglomeration between the particles. When the voltage is lower than the critical value, the electrostatic repulsive force on the solution is too small to overcome the surface tension, so the particles become agglomerated. When the voltage was too high, an unstable jet flow affected the sample morphology. Therefore, 18 kV was identified as the optimum voltage for preparing the B/NC/CuO powders.
The B/NC/CuO powders were pressed into an iron tube to form B/NC/CuO columns. The SEM images of the surface of the columns are depicted in Figure 5. The surface of the electrosprayed columns (Figure 5a,b) is smooth and dense, with a few cracks and holes. However, the samples obtained by the ball milling method (Figure 5c,d) possess a rough surface with many cracks and loose cavities. These can be seen from the red circle in Figure 5.
The results of Figure 4 and Figure 5 suggest that, compared with the ball milling method, the electrospraying method can improve the particle size distribution and dispersion of the samples. In addition, the surface of the sample prepared by the electrospraying method is denser and smoother than that of the ball-milled samples after pressing.

3.2. Effects of B Content on the Burning Rate of B/NC/CuO Thermite

The influence of B content on the burning rate of B/NC/CuO thermite is listed in Table 2. Each sample was tested 5 times. The burning rate of thermites initially decreased and then increased with an increase in B content. When B content becomes 15 wt%, the maximum burning rate will be 18.9 mm·s−1 (electrosprayed sample). However, the 0.32 standard deviation of the burning rate is the minimum when the content of B is 11 wt%. Moreover, when the B content is 11 wt%, the standard deviation of the burning rate of the electrosprayed sample is 32% lower than that of the ball milling sample. This suggests that the combustion performance of the samples prepared by the electrostatic spray method is more stable than that of the ball milling method. The SEM images (Figure 4 and Figure 5) reveal that the surfaces of ball-milling thermites are rougher and cracks more than those of electrosprayed samples, which leads to convection within the cracks and increases in voids. Therefore, the burning rate of ball-milling thermites is higher than that of electrosprayed samples. Moreover, compared with the ball-milling method, the electrospray method greatly increases the interfacial contact between particles and reduces the diffusion distance between B and CuO particles. This, in turn, results in a steadier reaction, manifesting a significant improvement in burning rate reproducibility.

3.3. Effects of Temperature on the Burning Rate of B/NC/CuO Thermite

The samples were placed in a vacuum oven at different temperatures (−50 °C, −30 °C, 0 °C, 30 °C, 55 °C) for 2 h and were examined within 5 min. Five measurement tests were performed on each sample, and the results are depicted in Figure 6. The burning rate of the samples should be independent of temperature changes, which is what we expect. However, the burning rate of thermites increases with the increase in temperature. When the B content is 11%, the burning rate range of 1.89 mm·s−1 (Table 3) is the minimum, and the burning rate range of 17 wt% B is the maximum (2.3 mm·s−1). The results indicate that the burning performance of B(11%)/NC/CuO thermite is more stable than the other B contents in the temperature range of −50 to 55 °C.

3.4. Effects of Ambient Pressure on the Burning Rate of B(11%)/NC/CuO Thermite

It can be concluded from the above results that the combustion performance of B(11%)/NC/CuO thermite is more stable than that of the other samples. Therefore, the influence of ambient pressures on the burning rate of B(11%)/NC/CuO thermite was examined via the method described in Part 2.5.2; the results are listed in Table 4. The u1, u2, and u3 are the results of three parallel tests on the same sample.
When the pressure is 0.02 MPa, the thermites can still be ignited. The burning rate of thermites should be independent of pressure changes, which is what we expect. However, the burning rate of the samples decreased with the decrease of pressure because part of the heat transfer within a thermite comes from convection, and convection decreases as pressure decreases. When the pressure was 0.1 MPa, the burning rate of B(11%)/NC/CuO thermite was 13.56 mm·s−1. At a pressure of 0.02 MPa, the burning rate of the sample becomes 13.11 mm·s−1, which is 3.3% lower than that at 0.1 MPa, indicating that the combustion performance of B/NC/CuO thermite was stable when the B content is 11% and at a pressure range of 0.02–0.1 MPa.

3.5. Laser Ignition Energy of B(11%)/NC/CuO Thermite

To solve the problem of thermites being difficult to ignite, the laser ignition energy of B(11%)/NC/CuO thermites was examined using a CO2 laser igniter. The result is shown in Table 5; columns 1–10 represent ignition tests carried out at 10 different laser energies, and 5 tests were carried out for each laser energy. Moreover, the combustion process of B/NC/CuO thermite was recorded by high-speed photography and is represented in Figure 7. The laser energy used for these 2 samples was 70 mJ. The minimum ignition energy of ball-milled B/NC/CuO thermite was 70 mJ, while that of electrosprayed thermite was as low as 45 mJ. The results indicate that the electrospray method can overcome the difficulties associated with the ignition of thermites and make it a facile process.
As depicted in Figure 7a, the electrosprayed B/NC/CuO thermite was ignited at 5.8 ms. The combustion was stable until it went out at 104 ms. The flame color was always orange red with smoke, as displayed in Figure 7a. The flame exhibited a cone shape, and the height continued to rise until 25.9 ms. The flame diffuses from the bottom to the top at 42.3 ms. The height reduces until the flame is extinguished at 104 ms.
The images of ball-milled thermites are presented in Figure 7b, showing that the ball-milled samples ignited at 1 ms. The light produced by the flame was feeble, and green light was visible in the front portion of the flame. The height of the flame increased in the middle stage (3.9–8.1 ms), and the color of the outer layer of the flame is green, the middle layer was yellow, and the inner layer was light white. The combustion of the flame is the fiercest at 8.1 ms. The color switched to golden yellow at 27.4 ms, and the flame extinguished at 60.5 ms.
The results of the study reveal that the time of ignition delay and combustion of electrosprayed thermites is longer than that of ball-milled ones when combustion is vigorous. The SEM results showed that the electrosprayed B/NC/CuO columns are denser and smoother with fewer cracks than ball-milled columns, which can be attributed to the decrease in the burning rate of electrosprayed columns. This also causes the reaction of electrosprayed samples to occur mainly in the condensed phase with small flame areas, resulting in few gas-phase products. The dense columns and fewer gas-phase products are favorable factors that improve the combustion stability of thermites.

3.6. Thermal Properties of B/NC/CuO Thermite

The DSC curves in Figure 8a correspond to thermites with different B contents prepared by ball milling. The experimental results (onset temperature, peak temperature, and heat release) are listed in Table 6. The results indicate that the initial temperature and peak temperature show insignificant changes with an increase in B content. When the B content is 11%, 998 mW/mg is the maximum heat release of thermite. The results coincide with the influence of B content on the burning rate of B/NC/CuO thermite. Therefore, we focused on comparing the DSC curves of electrosprayed or ball-milled samples corresponding to 11% B content.
Comparing the ball-milling B(11%)/NC/CuO thermite with the electrosprayed one, the results are shown in Figure 8b. An exothermic peak at 215 °C in DSC curves of electrosprayed and physical mixing (ball-milled) B/NC/CuO thermite was identified as the NC decomposition peak [30]. The main reaction peak of B and CuO occurs in the range of 550–650 °C. Compared to the ball-milled B/NC/CuO thermite, the peak temperature of the electrosprayed sample was dropped from 635.6 to 614.3 °C, with an increment of 21.3 °C. The DSC peak shift between electrosprayed and ball-milled samples may be due to differences in crack and morphology, or due to particle deposition in the process of electrospray leading to a composition change.

4. Conclusions

The electrospray method was employed to prepare the B/NC/CuO thermite. The particle diameter was identified to lie in the range of 3–4 μm to achieve uniformity and well dispersion. Compared with the traditional method, the electrospray method can improve the agglomeration and enhance the dispersion of nano particle.
The influence of B content and temperature on the burning rate of B/NC/CuO thermite was studied. The results indicated that the burning rate of B/NC/CuO thermite prepared by the electrospray method is lower than that of the traditional method, while the reproducibility of the burning rate is enhanced, and the minimal standard deviation is 0.32 mm⋅s−1. The burning rate of B/NC/CuO thermite increases with an increase in the B content. The combustion is found to be stable, and the burning rate increases from 13.35 to 15.24 mm·s−1 during −50–70 °C.
The effect of low pressure on the burning rate of B/NC/CuO thermite was also analyzed. The results illustrated that low pressure (0.02–0.1 MPa) had little effect on the burning rate of the B (11%)/NC/CuO thermite. Therefore, B (11%)/NC/CuO thermite can be used in low-pressure ignition conditions. The laser ignition energy of electrosprayed B(11%)/NC/CuO thermite was 45 mJ, which is lower than that of ball-milled thermite (70 mJ). This, in turn, overcomes the difficulties associated with the ignition of thermites.

Author Contributions

Conceptualization, Y.L. and D.S.; methodology, L.C. and J.W.; investigation, L.C. and J.W.; resource, H.Y. and P.G.; data curation, L.C. and J.W.; writing—original draft preparation, J.W.; writing—review and editing, Y.L. and D.S. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Funding of Southwest Technology and Engineering Research Institute (grant number HDHDW5903020202) and Chinese Ministry of Science and Technology (grant number 2019YFE0124000).

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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Metals 12 01419 g001 550
Figure 1. Schematic representation of the electrospray technique for the preparation of B/NC/CuO.
Figure 1. Schematic representation of the electrospray technique for the preparation of B/NC/CuO.
Metals 12 01419 g001
Metals 12 01419 g002 550
Figure 2. Structure of the iron tube into which the B/NC/CuO thermite sample is inserted.
Figure 2. Structure of the iron tube into which the B/NC/CuO thermite sample is inserted.
Metals 12 01419 g002
Metals 12 01419 g003 550
Figure 3. Schematic diagram of the burning rate test system.
Figure 3. Schematic diagram of the burning rate test system.
Metals 12 01419 g003
Metals 12 01419 g004 550
Figure 4. SEM results of the electrosprayed B (11%)/NC/CuO under (a,b) 16 kV, (c,d) 18 kV, (e,f) 20 kV, and ball-milled sample (g,h).
Figure 4. SEM results of the electrosprayed B (11%)/NC/CuO under (a,b) 16 kV, (c,d) 18 kV, (e,f) 20 kV, and ball-milled sample (g,h).
Metals 12 01419 g004
Metals 12 01419 g005 550
Figure 5. SEM results of the surface of B(11%)/NC/CuO thermite device via (a,b) electrospray and (c,d) ball milling.
Figure 5. SEM results of the surface of B(11%)/NC/CuO thermite device via (a,b) electrospray and (c,d) ball milling.
Metals 12 01419 g005
Metals 12 01419 g006 550
Figure 6. The influence of temperature on the burning rate of B/NC/CuO thermite.
Figure 6. The influence of temperature on the burning rate of B/NC/CuO thermite.
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Metals 12 01419 g007 550
Figure 7. Combustion process of B(11%)/NC/CuO thermite in the air: (a) electrosprayed; (b) ball-milled.
Figure 7. Combustion process of B(11%)/NC/CuO thermite in the air: (a) electrosprayed; (b) ball-milled.
Metals 12 01419 g007
Metals 12 01419 g008 550
Figure 8. (a) DSC curves of different B content of ball-milled B/NC/CuO thermite; (b) DSC curves of B(11%)/NC/CuO thermite.
Figure 8. (a) DSC curves of different B content of ball-milled B/NC/CuO thermite; (b) DSC curves of B(11%)/NC/CuO thermite.
Metals 12 01419 g008
Table
Table 1. Compositions of B/NC/CuO thermite.
Table 1. Compositions of B/NC/CuO thermite.
SamplesB (wt%)CuO (wt%)NC (wt%)
#18.388.73
#211863
#313873
#415823
#517803
Table
Table 2. The burning rate of the B/NC/CuO thermite device.
Table 2. The burning rate of the B/NC/CuO thermite device.
No.B Content
(%)		The Burning Rate of ElectrosprayedThe Burning Rate of Ball-Milled
Average
(mm·s−1)		Standard DeviationAverage
(mm·s−1)		Standard Deviation
18.713.81.7826.84.29
21113.60.3227.20.47
31316.10.9127.62.15
41518.90.3635.82.93
51718.01.5031.81.37
Table
Table 3. The burning rate range of B/NC/CuO thermites.
Table 3. The burning rate range of B/NC/CuO thermites.
Sample12345
Range/(mm·s−1)1.971.892.222.482.3
Table
Table 4. The burning rate of B(11%)/NC/CuO thermite device.
Table 4. The burning rate of B(11%)/NC/CuO thermite device.
Pressure/MPaBurning Rate u1/(mm/s)Burning Rate u2/(mm/s)Burning Rate u3/(mm/s)Average u/(mm/s)Standard Deviation/(mm/s)
0.113.5813.2013.8913.560.35
0.0713.6512.4813.8513.330.74
0.0512.5414.2713.4613.420.86
0.0212.6614.1612.5113.110.91
Table
Table 5. Results of laser ignition energy of B(11%)/NC/CuO thermite.
Table 5. Results of laser ignition energy of B(11%)/NC/CuO thermite.
Energy (mJ)90807069.56560504544.540
Ball-milled√√√×××××××
Electrosprayed√√√√√√√√××
Note: √ stands for ignited, × stands for misfired.
Table
Table 6. The parameters of ball-milled B/NC/CuO thermite.
Table 6. The parameters of ball-milled B/NC/CuO thermite.
SampleOnset Temperature (°C)Peak Temperature (°C)Heat Release (mW/mg)
1616.5641.6657.1
2613.3635.6998
3613.7636.4845
4611.5633.3829
5614.2636.5916
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Wang, J.; Yang, H.; Cheng, L.; Gao, P.; Li, Y.; Song, D. Ignition and Combustion Characteristics of B/NC/CuO Thermite Microparticles. Metals 2022, 12, 1419. https://doi.org/10.3390/met12091419

AMA Style

Wang J, Yang H, Cheng L, Gao P, Li Y, Song D. Ignition and Combustion Characteristics of B/NC/CuO Thermite Microparticles. Metals. 2022; 12(9):1419. https://doi.org/10.3390/met12091419

Chicago/Turabian Style

Wang, Jie, Hongtao Yang, Long Cheng, Pin Gao, Yanchun Li, and Dongming Song. 2022. "Ignition and Combustion Characteristics of B/NC/CuO Thermite Microparticles" Metals 12, no. 9: 1419. https://doi.org/10.3390/met12091419

APA Style

Wang, J., Yang, H., Cheng, L., Gao, P., Li, Y., & Song, D. (2022). Ignition and Combustion Characteristics of B/NC/CuO Thermite Microparticles. Metals, 12(9), 1419. https://doi.org/10.3390/met12091419

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