PURPOSE: To avoid influence given to a compact by evaporation gas and prevent the dispersion of copper component from the surface of an electrode by specifying starting material, density in molding and sintering temperature to perform sintering under an inactive atmosphere where a higher pressure than the vapor pressure of Cu is applied.
CONSTITUTION: Material powder containing copper powder is heated and molded into a compact which has the density being 65% or more of the theoretical density, and the obtained compact is heated under an inactive atmosphere where a higher pressure than the vapor pressure of copper is applied and at a lower temperature than the melting point of copper to form a compact, or an electrode 1. For example, Cu powder is used as starting material, which is filled into a metallic mold, pressurized and molded into a compact which has the density being 80% of the theoretical density. Next, the obtained compact is given heat treatment for two hours at 1060°C right under the melting point of Cu in a 5×10-5Torr vacuum in a vacuum furnace, while introducing argon as inactive gas therein under 0.2Torr partial pressure, to form a compact (electrode) 1. In this way, influence given by evaporation gas is avoided, the dispersion of copper component from the surface of the electrode is prevented and contact resistance is improved.
NODA TAIJI
TAMAKI NOBUAKI
