陶瓷烧结工艺的改进与创新对陶瓷材料制备技术的革新与优化有着重要意义。室温闪烧工艺具有烧结能耗低、成品陶瓷性能高的特点，已经成功制备钇稳定氧化锆和氧化锌等多类陶瓷材料。电弧诱导闪烧过程是室温闪烧中的特有现象，电弧产生机理及诱导闪烧发生的过程不清楚，明晰这一物理过程对室温闪烧工艺的改进具有现实意义。本文旨在通过有限元仿真手段和实验手段对电弧诱导闪烧全过程机理进行研究。首先，基于磁流体动力学方程、传热方程和麦克斯韦方程组，建立了电弧诱导闪烧的有限元仿真模型；试验研究氧化锆材料的室温闪烧过程，观测试验过程中电压电流变化情况，并测试成品陶瓷微观结构，电弧诱导行为会使得陶瓷晶粒尺寸不均。通过电弧诱导过程分析和起弧电压、稳定电压数值比对，验证了室温下电弧诱导闪烧有限元仿真模型的准确性。其次，对氧化锆材料电弧诱导闪烧发生过程进行了数值模拟。根据仿真结果，可以将氧化锆材料的室温闪烧过程分为三个阶段：电弧产生阶段，诱导闪烧发生、闪烧稳定阶段。计算了电弧与样品间的能量交换，电弧通过热辐射、热传导、表面烧蚀等方式向样品传导热量，其中热传导占据样品温度升高能量来源的80 %；研究了电弧诱导过程对样品内部温度分布的影响，电弧的出现会导致样品内部温度不均。增大样品的初始电导率、热导率能够缩短电弧作用时间，改善温度分布的均匀程度，从而提高试验成功率和成品陶瓷性能。氧化锆生坯本身的电导率、热导率大小范围是室温闪烧中电弧诱导闪烧这一独特现象出现的原因。最后，通过调整电弧诱导闪烧有限元仿真模型，对氧化铝材料的约束电弧闪烧过程进行了数值模拟，分析了不同气压下的电弧产生过程及电弧诱导闪烧发生过程机理，发现60 kPa是氧化铝约束电弧闪烧最适宜的气压。在室温下利用约束电弧闪烧工艺制备了高纯氧化铝陶瓷，深入讨论了样品表面导电通道形成过程。发现导电通道处的主要物质是三氧化钼，三氧化钼的形成是样品表面导电性增强的主要原因。
The improvement and innovation of ceramic sintering technology have significance to the innovation and optimization of ceramic material preparation technology. The room-temperature flash sintering technology has the characteristics of low energy consumption and high finished ceramic product performance, and has been able to prepare many kinds of ceramic materials such as yttrium stabilized zirconia and zinc oxide. Arc-induced flash sintering is a unique phenomenon in room-temperature flash sintering. The mechanism of arc generation and the process of arc-induced flash sintering is still unclear. It is of practical significance to clarify this physical process for the improvement of room-temperature flash sintering technology. The aim of this paper is to clarify the mechnism the whole process of arc-induced flash sintering by finite element simulation and experiment.Firstly, the finite element simulation model of arc induced flash sintering was established based on the magnetohydrodynamic equation, heat transfer equation and Maxwell equations. The process of flash sintering of zirconia material at room temperature was studied, the changes of voltage and current during the experiment were observed, and the microstructure of finished ceramics was tested. The arc induced behavior would make the ceramic grain size uneven. The accuracy of the finite element simulation model of arc induced flash sintering at room temperature was verified by analyzing the arc induction process and comparing the numerical values of striking voltage and stable voltage.Secondly, the arc induced flash sintering process of zirconia material was simulated numerically. According to the simulation results, the flash sintering process of zirconia material at room temperature could be divided into three stages: arc generation stage, induced flash sintering stage and flash sintering stable stage. The energy exchange between the arc and the sample was calculated. The arc transmitted heat to the sample by means of thermal radiation, thermal conduction and surface ablation, in which the heat conduction accounted for 80% of the energy source of the sample temperature increase. The effect of arc induction on the temperature distribution of the sample was studied. The presence of arc would lead to the uneven temperature of the sample. Increasing the initial electrical conductivity and thermal conductivity of the sample could shorten the arc action time and improve the uniformity of temperature distribution, so as to improve the test success rate and the performance of the finished ceramics. The range of conductivity and thermal conductivity of zirconia green billet was the reason for the unique phenomenon of arc induced flash sintering in room temperature flash burning.Finally, by adjusting the finite element simulation model of arc induced flash sintering, the constrained arc flash sintering process of alumina material was simulated, and the arc generation process and the mechanism of arc induced flash sintering under different pressure were analyzed. It was found that 60 kPa was the most suitable pressure for alumina confined arc flash sintering. High purity alumina ceramics were prepared by confined arc flash sintering at room temperature. The forming process of conductive channel on the sample surface was discussed in detail. It is found that the main substance in the conductive channel was molybdenum trioxide, and the formation of molybdenum trioxide was the reason for the enhancement of the electrical conductivity of the sample surface.
