Conductive adhesive is composed of non-conductive resin and conductive filler. Because epoxy resin has the advantages of excellent mechanical and thermal properties, low shrinkage rate, good bonding ability, resistance to mechanical shock and thermal shock, and strong resistance to humidity, solvents and chemical agents, etc., epoxy resin system conductive adhesive is the most studied.
As the key material for conductive adhesive to conduct electricity, conductive filler is also the main factor determining the cost of conductive adhesive. Conductive fillers such as gold, silver, copper, etc. Gold is the most reliable, but the most expensive. Copper is so easily oxidized that its electrical conductivity deteriorates. Silver powder is stable and has good electrical conductivity and becomes the most used conductive adhesive filler.
Conductive silver powder is generally divided into flake, spherical silver powder and silver-coated copper powder. The first two conductive silver powders are mainly introduced here.
At present, it is generally believed that the volume resistivity of the conductive adhesive using the same quality flake silver powder is smaller than that of the conductive adhesive using spherical Ag powder. This is mainly because the contact of the spherical silver powder in the conductive adhesive is point contact, while the flake one has surface-to-surface contact in addition to point contact, which can reduce the contact resistance of the overall conductive adhesive.
The current conductive adhesive filler flake silver powder is mainly prepared by ball milling, so there is a layer of organic substances on the surface of the flake silver, but if it cannot be removed after the conductive adhesive is cured, it will affect the performance of the conductive adhesive. In the process of mechanical ball milling of fine silver powder, oleic acid is generally added, which can promote the dispersion of silver powder in the resin more evenly, but at the same time, oleic acid is insulating, so the conductivity of the conductive adhesive will decrease. Therefore, it is necessary for us to deal with the silver powder.
Experiments show that after the silver powder is pickled, the insulating part of the surface is replaced, which can improve the electrical conductivity of the silver powder. However, due to the removal of oleic acid, the compatibility between silver powder and epoxy resin system is also deteriorated. After the silver powder is treated with the coupling agent, the dispersion in the conductive adhesive is more uniform, and the conductivity is also significantly improved.
In addition, the blending of a small amount of spherical silver powder and flake silver powder improves the conductivity of the conductive adhesive. This is because the added small amount of silver powder fills the gaps between the flakes of silver powder, making the original non-contact adjacent silver flakes contact each other, increasing the conductive path, or forming more parallel conductive paths in the conductive adhesive.
Hongwu Nano has professional and technical personnel with many years of experience in the research and development and production of conductive silver powder series materials to provide technical support for enterprises. At the same time, the company has established close cooperative relations with many domestic and foreign universities and scientific research institutions to ensure the sustainable development of the company. The company currently has an annual production capacity of tons of silver series powders.
Conductive flake silver powder and conductive spherical silver powder are reliable in quality, competitive in price and more favorable in bulk. Hongwu Nano is your first choice for cooperation.
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