Researchers fromPurdue University，专门从事能量学，热力学和添加剂制造，已经发明了一种使用增材制造的纳米米粉等能量材料的方法。
The group of seven researchers brought together energetics and combinatorial inkjet deposition technology to create a piezoelectric 3D printer, which is capable of depositing two substances sequentially on to a bed of substrate.
合并后，惰性材料形成了一种纳米热石，纳米热石，一种由纳米颗粒组成的物质，如果没有刺激，则不会释放其高能量。然后将3D打印的纳米热石的样品作为研究的一部分点燃，从而导致一系列受控爆炸以进行分析。
Depositing the thermite
Purdue PhD student Allison Murray constructed the 3D printer that was capable of depositing the nanothermite materials through extrusion. Murray’s 3D printer has a stationary nozzle, while the build platform below it moves to form whatever shape is required.
Functioning in a manner similar to a domestic inkjet printer (and some bio-printers), the 3D printer consists of a tube surrounded by material which flexes when a voltage is put through it. This flexing motion squeezes the tube, producing picoliter droplets. The droplet size could be varied by as little as 0.1 microns through varying the voltage.
The printer deposited two different inert colloidal suspension inks on to the Novele substrate. These two inks were a fuel consisting of nano-aluminium (nAl), and an oxidizer, nano-copper (II) oxide (nCuO). Since the inks were deposited in a sequence, they overlapped and mixed on the substrate producing a nanothermite.
Alternate singly and dually extruded 10×10 pixel square bitmap ink samples were prepared using single and dual nozzles. The dual nozzles deposited the fuel and the oxidizer separately, while the single nozzle deposited both together. Samples of 3, 5, and 7 layers in thickness were printed.
Testing the deposited thermite samples and experimental results
Each of the nanothermite samples was ignited electrically and analyzed using high-speed thermal imaging and scanning transmission electron microscopy (STEM). “It burns at 2,500 Kelvin [over 4,000 degrees Fahrenheit],” Murray said. “It generates a lot of thrust, a lot of heat, and makes a nice loud shockwave!”
Experimental data achieved by igniting the samples showed a 200K difference between the maximum reaction temperature of the dual and single samples respectively.Samples with 5 and 7 layers had overlapping bounds of peak reaction temperature.
在打印质量方面几乎没有差异，这表明双重喷嘴样品的可比较安全性比预混合的纳米热溶液更大，因为燃料和氧化剂分别存储。总体而言，它会产生多层结构，具有可调节的特征厚度和不同的反应速率，可以通过修改喷墨打印速率来实现。
3D打印符合能量学
穆雷指出：“这个项目的独特之处在于这两个领域的交汇处，并能够以这种精确度安全地存放能量材料。”
默里（Murray）主管杰弗里·罗德斯（Jeffrey Rhoads）补充说：“这是普渡大学（Purdue）的一个定义特征，来自不同背景的教授可以在这样的项目上共同努力。”“我们可以将所有经验结合在一起，以协作以前无法实现的技术。”
The results of this experiment will now be used in micro-mechanical energetics systems. Future research will now look at techniques for the bulk characterization of the samples, and study the effect of deposition’s shape on the overall energetic performance of the material.
A paper detailing the research, “Two-component additive manufacturing of nanothermite structures via reactive inkjet printing”艾莉森·穆雷（Allison K.
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Featured image shows infra-red slow motion imaging of the deposited energetic substance ignition. Gif via Purdue University.
