Abstract Silicon wafers with the thickness of approximately 250 μm were joined successfully using Al/NiO nano-thermite composites and with an aluminum foil interlayer (thickness of 30 μm), due to energy production from the exothermic reaction between Al (40 nm) and NiO (50 nm) powders. This reaction heat was subsequently transferred across the silicon wafer and reached the Si–Al–Si interface. This joining method reduces the possibility of introducing unwanted impurity and residual from the thermite reaction and subsequently improves the joint quality. Experimental data shows, adding Al micro-powder (5 μm, 60 % by mass) or Ni micro-powder (1 μm, 30 % by mass) into the nano-thermite composite was necessary and effective in joining the silicon wafer. The micro-hardness of the joined zone was measured as 129.3 ± 15.5 HV and 42.3 ± 4.0 HV for the Al and Ni micro-powder modified nano-thermite composites, respectively. The localized yield strength data confirmed the Al micro-powder produced a higher yield strength (350.6 ± 17.8 MPa) than the Ni micro-powder (327.1 ± 55.0 MPa). Energy production from the nano-thermite composites with different mixing ratios with the additive was characterized by Differential Scanning Calorimetry (DSC), and the apparent activation energy of the respective thermite reaction were calculated to investigate the effects of reaction kinetics to the joining process. The reduced joint quality produced by the Ni micro-powder modified Al/NiO nano-thermite composite was due to the low energy release from its thermite reaction (1.06 kJ/g), which was not sufficient to melt the silicon wafer. Moreover, the large activation energy of this thermite reaction (696.09 kJ/mol) hindered the joining process. In contrast, the Al micro-powder modified Al/NiO nano-thermite composite, via a two-step energy release process, produced sufficient energy (1.89 kJ/g) which led to a superior joint quality. In the first step, a pilot reaction (corresponding to the activation energy of 332.96 kJ/mol) between Al (40 nm) and NiO (50 nm) nanoparticles was dominant. In the following step, the reaction between Al micro-powder (5 μm) and NiO (50 nm) nanoparticles became significant and contributed greatly to successful joining.

中文翻译：

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Al-NiO 高能复合材料作为连接硅片的热源

摘要 由于 Al (40 nm) 和 NiO 之间的放热反应产生能量，使用 Al/NiO 纳米铝热复合材料和铝箔夹层（厚度为 30 μm）成功地连接了厚度约为 250 μm 的硅晶片。 (50 nm) 粉末。该反应热随后通过硅片传递并到达 Si-Al-Si 界面。这种连接方法减少了从铝热反应中引入不需要的杂质和残留物的可能性，从而提高了连接质量。实验数据表明，在纳米铝热剂复合材料中加入Al微粉（5μm，60%质量）或Ni微粉（1μm，30%质量）对连接硅片是必要且有效的。连接区的显微硬度测量为 129.3 ± 15.5 HV 和 42.3 ± 4。Al 和 Ni 微粉改性纳米铝热复合材料分别为 0 HV。局部屈服强度数据证实，铝微粉比镍微粉（327.1±55.0 MPa）产生更高的屈服强度（350.6 ± 17.8 MPa）。通过差示扫描量热法 (DSC) 表征了具有不同混合比与添加剂的纳米铝热剂复合材料的能量产生，并计算了各个铝热剂​​反应的表观活化能，以研究反应动力学对连接过程的影响。Ni微粉改性Al/NiO纳米铝热剂复合材料产生的接头质量降低是由于其铝热反应释放的能量低（1.06 kJ/g），不足以熔化硅片。此外，这种铝热剂反应的活化能很大（696. 09 kJ/mol) 阻碍了连接过程。相比之下，Al 微粉改性的 Al/NiO 纳米铝热复合材料，通过两步能量释放过程，产生了足够的能量 (1.89 kJ/g)，从而实现了优异的接头质量。在第一步中，Al (40 nm) 和 NiO (50 nm) 纳米粒子之间的先导反应（对应于 332.96 kJ/mol 的活化能）占主导地位。在接下来的步骤中，Al 微粉 (5 μm) 和 NiO (50 nm) 纳米粒子之间的反应变得显着，并极大地有助于成功连接。Al (40 nm) 和 NiO (50 nm) 纳米粒子之间的先导反应（对应于 332.96 kJ/mol 的活化能）占主导地位。在接下来的步骤中，Al 微粉 (5 μm) 和 NiO (50 nm) 纳米粒子之间的反应变得显着，并极大地有助于成功连接。Al (40 nm) 和 NiO (50 nm) 纳米粒子之间的先导反应（对应于 332.96 kJ/mol 的活化能）占主导地位。在接下来的步骤中，Al 微粉 (5 μm) 和 NiO (50 nm) 纳米粒子之间的反应变得显着，并极大地有助于成功连接。