How much does the amount of silver powder added affect the performance of conductive silver paste in conductive silver paste?

Conductive silver adhesiveIt is a special adhesive mainly composed of resin and conductive fillers (such as silver, gold, copper, nickel, tin and alloys, carbon powder, graphite, etc.), which can be used as an adhesive material in microelectronic components and packaging manufacturing processes.

LED conductive silver adhesiveThere are many types of conductive adhesives, and according to the different conductive particles, conductive adhesives can be divided into metal (powders of gold, silver, copper, aluminum, zinc, iron, nickel) conductive adhesives and carbon based conductive adhesives. In the above-mentioned conductive adhesive, due to the synthesis of silver powderNano conductive silver adhesiveIt has excellent conductivity, adhesion, and chemical stability. It is almost not oxidized in the adhesive layer and has a slow oxidation rate in air. Even if oxidized, the generated silver oxide still has good conductivity. Therefore, in the market, especially in electrical devices with high reliability requirements, conductive adhesives with silver powder as the conductive filler are most commonly used. In the selection of matrix resin, epoxy resin has become the preferred choice due to its high content of active groups, high cohesive strength, good adhesion, excellent mechanical properties, and excellent blending properties.

Silver powderAs a conductive filler added to epoxy adhesive, its conductive mechanism is the contact between silver powders. Before the conductive adhesive is cured and dried, the silver powder in the epoxy adhesive exists independently, without continuous contact with each other, and is in a non-conductive insulation state. After solidification and drying, due to the solidification of the system, the silver powders are interconnected into a chain like structure, forming a conductive network and exhibiting conductivity. After adding silver powder to the epoxy adhesive with good performance (toughening agent and curing agent dosage of 10% and 7% of the epoxy resin mass, respectively), its properties were tested after curing. According to experimental data, as silverSilver conductive adhesiveAs the filling amount increases, the volume resistivity decreases significantly. This is because when the silver powder content is too small, the amount of resin in the system is much higher than that of the conductive filler silver powder, making it difficult for the silver powder to contact and form an effective conductive network, resulting in higher resistance. With the increase of silver powder filling amount, the reduction of resin increases the contact of silver powder, which is conducive to the formation of conductive network and reduces the volume resistivity. When the filling amount is 80%, the volume resistivity is 0.9 × 10-4 Ω· cm, which has good conductivity.