Electrical properties of conductive adhesives as affected by particle compositions, particle shapes, and oxidizing temperatures of copper powders in a polymer matrix

The effects of particle compositions, particle shapes, and oxidation temperatures on the electrical properties of conductive adhesives have been investigated. Silver-coated copper powders and uncoated copper powders with spherical and flake-shaped particles are oxidized at temperatures such as 30, 175, 240, 300degreesC and 350degreesC for 2 h and dispersed in an epoxy matrix. The results of this study indicate that the electrical properties of the conductive adhesives are strongly affected by the particle compositions and oxidation temperatures and only slightly affected by the particle shapes. Silver-coated copper powders show significantly greater oxidation resistance than uncoated copper powders. To understand how silver-coated copper powders show such oxidation resistance, they are analyzed by the techniques of thermogravimetric analysis (TGA), X-ray diffraction (XRD), and Auger spectroscopy to observe how metal oxides such as AgO, Cu2O, and CuO affect the electrical properties of the conductive adhesives. (C) 2004 Wiley Periodicals, Inc.