Effect of TiB2 Particle Size on Erosion Behavior of Ag-4wt% TiB2 Composite

摘要:

为了研究不同粒度TiB2对Ag-TiB2复合材料电弧侵蚀行为的影响，通过机械球磨和粉末冶金的方法制备不同粒度的TiB2增强Ag-4%TiB2(质量分数)复合材料。对Ag-4%TiB2复合材料的组织进行了分析，定量分析了TiB2的分布。用TDR240A单晶炉改装的设备进行真空电弧侵蚀实验，采用扫描电子显微镜(SEM)表征了电弧侵蚀后试样表面形貌，测量了电弧侵蚀前后的质量损失，采用TDS-2014双通道数字示波器记录了每次电弧的持续时间，并且对电弧侵蚀机理进行了讨论。结果显示，随着TiB2颗粒粒度的减小，TiB2颗粒在Ag基体分布更均匀，Ag-4%TiB2触头材料表现出小的质量损失，短的电弧持续时间，大的侵蚀区域以及浅的侵蚀坑。说明了细小TiB2颗粒更能有效改善Ag-4%TiB2触头材料的耐电弧侵蚀性能。

Abstract:

In order to clarify the effect of TiB2 particle size on the arc erosion behavior of Ag-TiB2 composite, Ag-4wt%TiB2 composite reinforced by different grain-sized TiB2 particles was prepared by mechanical milling and powder metallurgy. The microstructures of Ag-4wt%TiB2 composites were analyzed, and the global distribution of TiB2 particles was quantitatively evaluated by the enumeration method. The vacuum arc erosion of Ag-4wt%TiB2 composite was tested in a modified TDR240A single crystal furnace. The surface morphology of the Ag-4wt%TiB2 composite after arc erosion was characterized. The mass losses before and after arc erosion were measured. The arc duration was determined by the discharged waveform recorded by a Tektronix TDS-2014 dual channel digital memory oscilloscope, and the arc erosion mechanism was discussed as well. The results show that with the decrease of TiB2 particle size, the TiB2 particles are more uniformly dispersed in the Ag matrix, and Ag-4wt%TiB2 composite presents less mass loss, shorter arc duration, larger arc erosion area and shallower erosion pits. It suggests that fine TiB2 particle can effectively improve the arc erosion resistance of the Ag-4wt%TiB2 composite.