Briefly Introduction about Conductive Silver Paste in Flexible Circuits (1)

Conductive Silver Paste is widely used in flexible circuits especial membrane switches industry.

Silver paste is a viscous paste composed of high-purity (99.9%) metallic silver particles, binders, solvents, and additives.

The metal silver particles are the main component of the conductive silver paste, and the conductive properties of the membrane switch are mainly reflected by it. 

The content of metallic silver in the paste is directly related to the electrical conductivity. 

In a sense, the high content of silver is beneficial to improve its conductivity, but when its content exceeds the critical volume concentration, its conductivity cannot be improved. 

When the silver content is generally 80-90% (weight ratio), the electrical conductivity has reached the highest value. 

When the content continues to increase, the electrical properties no longer increase, and the resistance value shows an upward trend; when the content is less than 60%, the resistance changes Unstable. In specific applications, the content of silver particles in the silver paste should not only consider the stable resistance value, but also be restricted by factors such as curing characteristics, adhesion strength, and economy. 

For example, if the content of silver particles is too high, the probability of being covered by the bonding resin Low, the adhesion of the silver conductor decreases after curing to form a film, and there is a risk of the silver particles falling off. 

Therefore, the content of silver in the silver paste is generally 60 to 70% is suitable.