Microwave sintering is a novel and efficient technology for the rapid preparation of metallic materials. In this paper, an investigation has been performed on the distribution of microwave electromagnetic fields in a metallic particle system and its influence on sintering behavior. The results show that the microstructure of the “metallic-void” will induce a nonuniform distribution and focusing effect of electromagnetic fields during microwave processing, which may accelerate the sintering process. However, further study shows that the focusing effect will decline as the neck grows larger, and will also decline from outside to inside within the loosely packed powder system, which will result in the slowdown of the sintering rate. These results were supported by the synchrotron radiation computed tomography experimental observation of the microstructure evolution of metallic powders during an entire uninterrupted microwave sintering process.
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This work was supported by National Nature Science Foundation of China under the Contract Nos. 11272305, 11402160 and 11390362. The authors warmly thank Niu Yu, Hongyan Qu and Kang Dan for the assistance in conducting the experiment.
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Li, Y., Xu, F., Hu, X. et al. Focusing effect of electromagnetic fields and its influence on sintering during the microwave processing of metallic particles. Journal of Materials Research 30, 3663–3670 (2015). https://doi.org/10.1557/jmr.2015.344