利用高频交流电提高闪烧均匀性：趋肤效应的作用

闪烧技术自发现以来已经被广泛研究了10多年，但其实际应用却极少被讨论，闪烧应用的主要挑战是烧结大尺寸样品时的困难。在典型直流电闪烧中，电流主要集中在样品的中心，样品内部和表面之间存在显著的温度梯度，导致最终样品的微观结构不均匀，甚至样品中的内应力会致使样品开裂。本工作利用不同频率的交流电来研究频率对闪烧中这种不均匀性问题的影响。结果表明，增加频率显著提高了样品的均匀性，其原因主要是由于交流电闪烧中存在显著的“趋肤效应”，即电流密度集中在样品的表面而不是样品中心，这补偿了表面较高的辐射热损失，从而导致更均匀的样品温度。本工作提供了一种潜在的方法，可以显著提高闪烧在工业领域的实际应用。

Abstract

Flash sintering is extensively investigated for over a decade since its discovery, but its practical application is seldomly discussed. A primary challenge in utilizing flash sintering is a difficulty in sintering large samples. This is since in a typical direct current (DC) flash sintering, the current is concentrated primarily in the center of the sample, causing a significant temperature gradient between the interior and surface of the sample, thus leading to an inhomogeneous microstructure in the final product and sometimes large stresses in the sample that breaks the material. In this paper, we utilized the alternating current (AC) with varying frequencies to investigate its effect on this inhomogeneity issue in flash sintering. The results indicate that increasing the frequency significantly enhances the uniformity of the sample. The underlying mechanism is related to a significant “skin effect” in AC flash sintering, where the current density is concentrated on the surface of the sample rather than its center, compensating for a higher radiation heat loss at the surface and resulting in a more uniform sample temperature. This work provides a potential approach to enhance the flash sintering for industrial applications.

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肖巍伟, 余亚丽, 赵晓峰, 倪娜. 利用高频交流电提高闪烧均匀性：趋肤效应的作用[J]. 硅酸盐学报, 2023, 51(12): 3077. XIAO Weiwei, YU Yali, ZHAO Xiaofeng, NI Na. Enhancing Uniformity in Flash Sintering Through High-Frequency Alternating Current - Role of Skin Effect[J]. Journal of the Chinese Ceramic Society, 2023, 51(12): 3077.

利用高频交流电提高闪烧均匀性：趋肤效应的作用

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