Ag/ZnO/La2Sn2O7复合材料在N2、CO2及其与c-C4F8混合物中的电弧侵蚀行为及机理

Arc-Erosion Behavior and Mechanism of Ag/ZnO/La2Sn2O7 Composites in N2, CO2 and Their Mixtures with c-C4F8

摘要:

通过化学共沉淀法合成了La₂Sn₂O₇粉末，并通过热压烧结法制备了Ag/ZnO/La₂Sn₂O₇复合材料。研究了复合材料在7 kV恒定电压下在CO₂、N₂、CO₂/c-C₄F₈和N₂/c-C₄F₈混合气体中的电弧烧蚀行为和机理。实验结果表明，不同大气压下电弧击穿电流差异非常小，而混合气体中的烧蚀面积、电弧能量和电弧持续时间明显小于CO₂和N₂。随着c-C₄F₈含量的增加，混合气体中的击穿强度逐渐增加，且均高于CO₂和N₂中的击穿强度。电弧光学图像表明，混合气体中的电弧体积明显小于CO₂和N₂单一气体中的电弧体积，且随着c-C₄F₈含量的增加，电弧体积逐渐减小。烧蚀形貌分析表明，CO₂和N₂电弧烧蚀后复合材料中存在较多的孔隙、飞溅颗粒和裂纹。在混合气体中，N₂/c-C₄F₈（80/20）混合气体的烧蚀面积最小，颗粒和孔隙明显减少。在N₂/c-C₄F₈混合物中观察到的低电弧能量显著降低了电弧体积和烧蚀面积。X射线光电子能谱显示La₂Sn₂O₇部分分解为La₂O₃和SnO₂，而在含有c-C₄F₈的混合气体的烧蚀表面上检测出AgF和CF_x的存在。

Abstract:

La₂Sn₂O₇ powder was synthesized via chemical co-precipitation, and the Ag/ZnO/La₂Sn₂O₇ composites were prepared by hot-pressed sintering. The arc-erosion behavior and mechanisms of the composites were investigated at a constant voltage of 7 kV in CO₂, N₂, CO₂/c-C₄F₈, and N₂/c-C₄F₈ mixtures. The results show that the difference in arc breakdown current is very small across different atmospheres, while the erosion area, arc energy, and arc duration in mixed gas are clearly smaller than those in CO₂ and N₂. As the content of c-C₄F₈ rises, the breakdown strength in mixed gas increases gradually and is higher than that in CO₂ and N₂. The optical images of the arc show that the arc volume in mixed gas is obviously smaller than that in single-gas CO₂ or N₂, and the arc volume decreases gradually with the increase in c-C₄F₈ content. The erosion morphology analysis indicates that more pores, spattered particles, and cracks are present in the composites after arc-erosion in CO₂ and N₂. In the gas mixture, the erosion area is the smallest in the N₂/c-C₄F₈ (80/20) mixture, and particles and pores are significantly reduced. The low arc energy observed in N₂/c-C₄F₈ mixtures significantly reduces arc volume and erosion area. X-ray photoelectron spectroscopy results reveal partial decomposition of La₂Sn₂O₇ into La₂O₃ and SnO₂, while AgF and CF_x compounds are identified on eroded surfaces in c-C₄F₈ containing mixtures.