Conductive adhesive and its use

It is not easy to imagine the modern world without an abundance of electronics and computers. But how many people know that conductive adhesives have been widely used in the construction of modern electronic devices for a long time? This class of adhesives is designed to provide not only a reliable connection of electronic components, microcircuits and other parts of various electrical appliances, but also suitable electrical and thermal resistance.

What is a conductive adhesive and where and how is it used? The main requirement for an electrically conductive adhesive is minimum resistance and low thermal resistance. In addition, such an adhesive must provide a strong, reliable and durable contact.

To obtain glue with stable electrical conductivity characteristics, nickel or finely dispersed silver, palladium or even gold dust is added to its composition. So, the more conductive additives in the glue, the higher its conductive properties, but the bond strength decreases due to the large amount of additives.

To give the glue greater elasticity, while maintaining the electrical conductivity and strength of the joints, a polymer binder is added to the glue. The polymer binder is also designed to provide high adhesion as well as reduce glue density. Some brands of glue with stable parameters electrical resistance, differ in that in their binder the metal particles are structured by a magnetic field. This method of stabilizing the adhesive resistance is very cheap and convenient.

With the help of electrically conductive adhesives, switching layers are formed on aluminum and polymer substrates; thanks to conductive glue, piezoceramic plates are connected, semiconductors and microcircuits are mounted on boards. The adhesive adds vibration and shock resistance to electrical circuits and makes them resistant to regular temperature changes.

Conductive glue Kontakol, which is produced by both foreign and domestic manufacturers, is very popular today. Kontakol glue is a viscous composition based on synthetic resins.

Silver is used here as a conductive filler in the form of finely dispersed powder (as mentioned above, in other adhesives silver is replaced by palladium or even gold). The viscosity of this glue can be different, it is worth adding a solvent in a certain amount, for example acetone, isopropyl alcohol or cyclohexanone, and thus get a less or more viscous conductive glue.

Kontol is widely used to provide communications on dielectric panels, in the repair of heating elements of car windows (windshield or rear).In addition, this glue can become the basis for conductive enamel used in tooling.

If you wish, conductive glue can easily be made yourself at home. Any radio amateur will cope with this simple task. If there is a need to mount microcircuits using conductive glue or repair household appliances using it, then you can simply mix cheap and at the same time widely available components. In general, there are different techniques, and here are the most popular:

• Cedar varnish is used as a binder. Add a part of the graphite powder and a few parts of copper shavings;

• As a binder - superglue in a tube. Add graphite powder in a ratio of 1 to 1. Mix with a match and the conductive glue is ready;

• Graphite powder is added to tsaponlak, mixing to a consistency close to thick sour cream. Such a mass is weakly glued, but the conductivity is excellent;

• 6 grams of graphite powder is mixed with 60 grams of silver powder, then a binder is prepared from 4 grams of nitrocellulose, 2.5 grams of rosin and 30 grams of acetone; mix the powder in a binder — a conductive glue is obtained;

• 1 to 2 mix the graphite powder and silver, then add 2 parts of vinyl chloride and vinyl acetate copolymer. The result is a conductive adhesive with high electrical conductivity, giving excellent bond strength. The viscosity of the mixture can be adjusted with acetone.