Ag-CdO合金是制造开关电器的触头材料之一。由于它具有抗熔焊、耐电弧烧损及良好的灭弧性能因而在开关电器中获得广泛的应用。在研制Ag-CdO合金材料时曾发现,低压开关电器在分断大电流时往往会发生电流过零后的电弧重燃,严重时甚至会因持续燃弧而把触头烧毁,而且这个现象往往发生在新触头第一次分断的时候。如果第一次分断时触头不被烧毁,则第二次分断的燃弧时间便会明显地缩短,而且能满足使用要求。金相研究结果表明,在这种合金表面存在着一层厚度为0.01～0.02mm、组织较松散而结构异常的表层。多次实验表明,当有这层表面存在时,电弧重燃现象将大大加剧;若去掉此表层,则电弧重燃 Ag-CdO alloy is one of the contact materials used to make switchgear. Because of its anti-welding, arc erosion and good arc-extinguishing performance and therefore in the switch electrical appliances are widely used. In the development of Ag-CdO alloy materials, it has been found that the low-voltage switchgear often occurs when the current breaking off the arc after the current reclosing, in severe cases even because the arc will continue burning the contacts, and this phenomenon often occurs When the new contact is broken for the first time. If the contact is not burned when the first time is broken, the arcing time of the second breaking will be obviously shortened and the requirement of use can be met. Metallographic studies have shown that there is a layer of 0.01 ~ 0.02mm in thickness on the surface of the alloy, the structure is loose and abnormal structure of the surface layer. Repeated experiments show that when there is this layer surface, the phenomenon of arc reignition will be greatly exacerbated; if the surface is removed, the arc reignition