Abstract The densification mechanism of conductive powders is revealed by comparing the electric current-assisted spark plasma sintering (SPS) of ZrN powder with conventional hot pressing (HP) carried out with the same powder and under the same pressure and temperature. To determine the actual temperature inside ZrN powder, a sacrificial thermocouple is directly inserted into the powder during the SPS process. The spatial distribution of the electric current passing through the powder is calculated using the finite element modeling. The porosity-interparticle neck area geometrical relationship is applied to estimate the electric current density inside the powder volume subjected to SPS. For the first time, by taking into account the explicit influence of the electric current effect on the SPS densification mechanism, the constitutive equations describing the electric current-assisted hot pressing of powders are developed. The densification mechanism of ZrN is determined by the inverse regression of the new SPS constitutive equations and by utilizing the experimental results on ZrN powder consolidation with and without the participation of the electric current effect.

中文翻译：

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电流对放电等离子烧结导电陶瓷粉末致密化行为的影响

摘要 通过将ZrN 粉末的电流辅助放电等离子体烧结（SPS）与相同粉末、相同压力和温度下的常规热压（HP）进行比较，揭示了导电粉末的致密化机制。为了确定 ZrN 粉末内部的实际温度，在 SPS 过程中将牺牲热电偶直接插入粉末中。使用有限元建模计算通过粉末的电流的空间分布。孔隙率-颗粒间颈部面积几何关系用于估计粉末体积内经受 SPS 的电流密度。首次通过考虑电流效应对 SPS 致密化机制的显性影响，开发了描述粉末电流辅助热压的本构方程。ZrN 的致密化机制是通过新 SPS 本构方程的逆回归和利用 ZrN 粉末固结的实验结果确定的，有和没有电流效应的参与。