银金属氧化物触头材料电弧侵蚀的新型物理－数学模型

为深入理解ＡｇＭｅＯ材料的电弧侵蚀物理过程，基于大量的试验结果，着重分析了电弧能量输入所引起的材料响应过程，特别是材料的物相变化及高温态组织结构特性、粘度、熔化态表面张力等对电弧侵蚀的影响，从电弧侵蚀的两种基本形式即气化蒸发和液态喷溅在不同电流下所起的作用，得出材料物相变化的两个界面分别对应材料电弧侵蚀量的上下限。通过材料组分的热力学性质、材料组织结构及电弧的动力响应对电弧侵蚀机理的影响，建立了简明的材料电弧侵蚀物理模型。最后，在假定电弧弧柱为“点状热源”的基础上，运用有限差分方法对电弧侵蚀物理过程进行了数学模拟，计算结果表明：计算值与试验值吻合良好。

NEWE EROSION MODEL OF AgMeO CONTACT MATERIALS

Based on switching experiments with cylindrical contacts of different diameters by highspeed camera observations and SEM micrographs,the effects of phase change,viscosity andsurface tension on erosion losses of AgMeO contact materials were analysed during arcing inthe current range up to 1000A rms.The erosion model of AgMeO was used for expressingthe heat-force function during arc-electrode interaction and the liquid-solid,liquid-gasboundary corresponding to upper and lower erosion limit,respectively,for the reason thaterosion is composed of two modes :evaporation and minute molten droplets losses. Further-more,suppose the arc column is a hypothetical point heat source in the middle of the gap,anew erosion mathematical model was established by finite difference method and the resultscoincided with those of experiments.