Discussion on Local Spark Sintering of a Ceramic-Metal System in an SR-CT Experiment during Microwave Processing.
Discussion on Local Spark Sintering of a Ceramic-Metal System in an SR-CT Experiment during Microwave Processing.
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微波处理期间 SR-CT 实验中陶瓷-金属系统局部火花烧结的讨论
DOI：
10.3390/ma9030132
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发表时间：
2016-02-26
期刊：
影响因子：
--
通讯作者：
Xiao Y
中科院分区：
文献类型：
--
作者：
Li Y;Xu F;Hu X;Dong B;Luan Y;Xiao Y
本文利用同步辐射CT技术研究了微波处理下SiO_2-Sn陶瓷-金属系统的局部放电烧结过程。从样品的三维重建图像和截面图像可以看出，在Sn熔点以下，样品发生了致密化过程，然后进入快速致密化阶段。这些结果可能是由于高频交变微波电场诱导的局部放电烧结所致。当引入金属颗粒Sn时，“陶瓷-金属”的微结构将导致在某些区域（例如，脖子）。这将导致高强度电场，然后在微区域内诱导快速火花烧结。然而，在随后的阶段，致密化速率下降，即使试样是不够致密。这是由于液态Sn渗入SiO2之间的间隙，样品变得致密，电场的微聚焦效应降低。这可能导致火花烧结的减少或消失。这些结果将有助于理解微波烧结机理和改进微波加工方法。
In this paper, local spark sintering of a ceramic-metal system (SiO2-Sn) during microwave processing was examinedby means of synchrotron-radiation-computed tomography technology. From the reconstructed 3-D and cross-section images of the specimen, adensification process was observed below the melting point of Sn, and then the specimen came into a rapid densification stage. These results may be due to the local spark sintering induced by the high-frequency alternating microwave electric fields. As the metallic particles Sn were introduced, the microstructure of “ceramic-metal” will lead to a non-uniform distribution and micro-focusing effect from electric fields in some regions (e.g., the neck). This will result in high-intensity electric fields and then induce rapid spark sintering within the micro-region. However, in the subsequent stage, the densification rate declined even when the specimen was not dense enough. The explanation for this is that as the liquid Sn permeated the gaps between SiO2, the specimen became dense and the micro-focusing effect of electric fields decreased. This may result in the decrease or disappearance of spark sintering. These results will contribute to the understanding of microwave sintering mechanisms and the improvement of microwave processing methods.