Abstract: A novel distributor rotor electrode material is provided and a method for making it. A mixture comprised of at least half copper oxide and a minor portion of silica or silica and alumina is fused to form a friable glassy material. The copper oxide of the material is reduced to copper metal, the material in the solid state then being characterized by a substantially continuous microphase of sponge-shaped glassy bodies with copper retained in the interstices thereof. When the material is sintered into a rotor electrode body, the sponge-shaped bodies become strongly mechanically retained in a substantially continuous metal matrix providing the electrode with outstanding resistance to spark erosion.