Investigation of reactive bimetallic Ni-Al particles as a heat source for microwave-assisted joining
Investigation of reactive bimetallic Ni-Al particles as a heat source for microwave-assisted joining
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DOI：
10.1016/j.jmatprotec.2020.116637
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发表时间：
2020-08
影响因子：
6.3
通讯作者：
S. Grohmann;G. Langhans;A. Reindl;V. Sidarava;M. F. Zaeh
中科院分区：
文献类型：
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作者：
S. Grohmann;G. Langhans;A. Reindl;V. Sidarava;M. F. Zaeh
具有不同热物理性质的材料的热接合需要有效且适应性强的能量输入，而不会导致接合伙伴的热损伤。反应性颗粒为此目的提供了一种有前途的解决方案，因为它们通过能够经历放热的、自维持的反应而代表可定制的热源。引发反应的复杂方法是使用微波，因为它们允许高加热速率、体积加热，并且甚至在活化之后也可能影响反应。通过这种方式，由镍和铝组成的颗粒可以在几百毫秒内产生高达1550 K的温度。然而，高反应速率，高温，仍然没有完全理解的微波特定的现象复杂的因果关系的推导。因此，开发了一种实验装置，其中由于定制的谐振腔，反应性颗粒可以在主导磁场或电场中被激活。详细的高温和几种功率测量方法，实现了一个层状本征结构的颗粒的激活和反应行为。电磁场和颗粒尺寸都影响所得到的温度-时间曲线和电弧现象。为了证明反应性颗粒的潜力，它们也被用作微波辅助粘合剂粘合中的新热源。经验研究表明，微波和反应性颗粒以有利的方式与环氧树脂相互作用，促进聚合物的交联，并允许在微波腔中制造聚丙烯接头。
Thermal joining of materials with dissimilar thermo-physical properties requires an efficient and adaptable energy input that does not lead to thermal damage of the joining partners. Reactive particles provide a promising solution for this purpose as they represent a tailorable heat source by being able to undergo an exothermic, self-sustaining reaction. A sophisticated method of initiating the reaction is the use of microwaves, since they allow high heating rates, volumetric heating, and may influence the reaction even after the activation. In this way, particles consisting of nickel and aluminium can generate temperatures up to 1550 K within a few hundred milliseconds. However, high reaction rates, elevated temperatures, and still not fully understood microwave-specific phenomena complicate the derivation of cause-effect relationships. Therefore, an experimental set-up was developed, in which the reactive particles can be activated either in the predominant magnetic or electric field due to a customised resonant cavity. Elaborate high-temperature and several power measurement methods were implemented to characterise the activation and reaction behaviour of particles with a lamellar intrinsic structure. Both the electromagnetic field and the particle size influenced the resulting temperature-time profiles and arcing phenomena. In order to demonstrate the potential of reactive particles, they were also used as a new heat source in microwave-assisted adhesive bonding. An empirical study showed that microwaves and reactive particles interacted in an advantageous way with epoxy resins, promoted the cross-linking of the polymers, and allowed the fabrication of polypropylene joints in the microwave cavity.