Surface Modification of Ag Coated Cu Conductive Metal Powder for Conductive Silicone Sealant Gasket Paste

Abstract

Conductive pastes have drawn significant interest due to their advantageous physical properties as well as their potential in electronic material industries. Conductive pastes consist of conductive fillers, organic binders, solvents and additives. Metal powders, such as Au, Ag, Ni, Cu, etc. are used for conductive filler. Filler dispersion is a very important and yet a difficult process in conductive paste manufacturing. Meanwhile, there are some metal powders such as copper, nickel etc that are used for pastes which have serious surface corrosion problems. This problem leads to change of the color and decrease in conductivity and affect storage stability of conductive pastes. To overcome these problems, we adopted two kinds of surface modification method. One is a method involving coating of silane coupling agent to conductive metal powders to overcome the corrosion stability and the other is a method involving addition of a dispersing agent to increase the degree of dispersion of metal powders. A coupling agent and dispersing agent are used to reduce the interfacial energy between filler and organic binder to enhance dispersion and its stability. By using silane coupling agent and dispersion agent, we can ensure both the corrosion stability and long term storage stability, and enhance the high performance electrical and mechanical properties of EMI shielding silicone sealant.