Conductive paint is a popular name. There are many products called conductive paint on the market. It can be divided into two categories according to application, conductivity and material. That is, metal conductive paint and non-metal conductive paint. Nonmetallic conductive paint is a kind of common paint which can conduct electricity by adding some additives. Its conductivity is usually in the range of tens of thousands to millions of ohms. Mainly used for anti-static function, such as: floor paint.
Here we mainly talk about the classification and function of metal conductive paint.
Conductive paint for metallization and shielding. The added conductive powder is limited to silver, copper and nickel, or composite or mixed materials of the three materials. Either conductivity is very good.
Metal conductive paint is mainly divided into the following four categories:
The material of silver is called silver conductive paint. Conductivity is the best of all materials, but the price of silver is very expensive, so the price of conductive paint is generally between two to three thousand yuan a kilogram. Only military, medical equipment, high-end communication equipment and other products are affordable.
Copper is also called pure copper conductive paint. Conductivity is also very good, but copper is very easy to oxidize, oxidized copper is not conductive. At present, pure copper conductive paint is only used as electroplating interlayer of non-metallic materials. Water plating can only be carried out by making non-metallic materials conductive. Its oxidation does not affect the process in a few days.
Silver copper conductive paint is the most popular one on the market. The combination of silver and copper is the best way to solve the problems of expensive silver paint and easy oxidation of copper paint. The adjustment of performance and cost is very flexible, which depends on the proportion of silver and copper. The conductivity of silver copper conductive paint is closer to that of silver and the cost is closer to that of copper, so this type of conductive paint is almost universal. The combination mentioned here is not a simple physical mixing, but a close combination through chemical replacement. Generally, the preparation process is to grind and polish the copper powder, activate it, and then plating a layer of silver on its surface with silver nitrate ion aqueous solution, so that the silver completely covers the copper. In this way, the oxidation of copper can be prevented, and the conductivity of the surface is increased.
Nickel conductive paint is a kind of conductive paint made of nickel metal powder. Nickel itself is stable and corrosion-resistant, but among the four conductive paints, the one with the worst conductivity has a resistance of about two ohms. The color is grey black, which is suitable for the products with corrosion resistance and color requirements.