电极材料组织对真空电弧阴极斑点运动行为的影响

真空电弧在非晶、纳米晶及常规粗品电极合金表面微观分布的观测表明，电极材料显微组织对电弧阴极斑点几何性质和运动行为有明显影响．阴极斑点优先在材料承载电压能力低的弱相表面形成，弱相尺寸、形貌和分布决定了阴极斑点的几何特征．显微组织大幅度细化时，电弧在电极表面分散和快速运动，非晶合金表面仍保持完全非晶结构．分析表明，当材料特征显微组织尺寸小于阴极斑点尺寸时，阴极斑点运动模式从跳跃式运动转变为连续式运动．电极材料组成相的浓度及其尺寸是决定阴极斑点微观迁移方式的重要因素．

INFLUENCE OF THE MICROSTRUCTURE OF ELECTRODE MATERIALS ON THE MOTION BEHAVIORS OF VACUUM ARC CATHODE SPOT

Role of the microstructure of cathode materials in the geometrical parameter and migration process of cathode spot is studied on the basis of the observation of microscopic trace of vacuum arc without external magnetic field. Arc erosion pattern shows that spot craters locate on the phases with weak voltage withstanding, whose size, morphology and distribution determine the character of the arc spots. For the cathode alloys with ultra-fine microstructure the spot is dispersed and moves quickly on the cathode surface, indicating the spot motion is controlled by the microstructure of the electrode materials. The spot migration mode changes from the jumping motion to a continuous one when the microstructure scale is less than the spot size. It is concluded that the constituent phases and their sizes are the important factor dominating the microscopic migration mode of arc cathode spots.