Xinyu Tips to Prevent Corrosion of Copper Clad Aluminum Wire

Summary: Copper-clad aluminum wire is a wire with aluminum core wire as the main body and a certain amount o...

Copper-clad aluminum wire is a wire with aluminum core wire as the main body and a certain amount of copper plated on the outside. It can be used as a conductor for coaxial cables and wire and cable conductors in electrical equipment. Because the main function of this kind of wire is to transmit signals, the current flowing through it is very small. In particular, high-frequency signal transmission runs completely on the outer layer of the wire, so the copper-clad aluminum wire can replace the copper wire of the same specification.

Compared with pure copper wire, copper-clad aluminum wire has obvious advantages: first, it is light in weight, convenient for transportation and installation, and can reduce labor costs; second, it has obvious economic benefits. The separation of the core wire is almost impossible, and it can also receive an additional anti-theft effect.

However, in addition to people's inherent prejudice, copper-clad aluminum wire has the disadvantage that it is more corrosive than copper wire, which restricts its development and promotion. How to prevent the copper clad aluminum wire from being corroded has become the key to its promotion and application.

Copper and aluminum in the copper-clad aluminum wire are two metals with different electrode potentials. Copper and aluminum are exposed to the atmosphere on its end surface. If the humidity in the atmosphere is high, the end surface will adsorb small water molecules and accumulate into small water droplets. . Because there are coal incineration products or exhaust gas from many motor vehicles in the atmosphere, which is rich in SO2. SO2 is oxidized into SO3 in the air, and dissolved in small water droplets to form the H2SO4 that corrodes the battery that occurs in the acid solution, and then becomes an electrolyte solution, which corrodes the battery. In this corrosion cell, aluminum is corroded because of its low electrode potential. Even if it is a piece of metal that does not touch other metals and is placed in an electrolyte solution, corrosion similar to the above will occur. For example, copper is often rich in a few impurities, and the potential of the impurities is usually higher than that of copper. When there are acidic water droplets on the surface of the copper, the battery is formed and the copper is corroded.

In order to avoid electrochemical corrosion of the copper clad aluminum wire end, the better way is to block the end from the atmosphere and avoid the corrosion of the copper clad aluminum wire. Two methods are currently available:

   1. Electroplating method to avoid corrosion of copper clad aluminum wire: plating a layer of copper on the butt joint of the copper clad aluminum wire, but it takes too much time (40 minutes). However, it is not a big problem in the company that produces copper-clad aluminum wire, because many joints can be electroplated together. Copper plating on the surface of aluminum is difficult.

   2. The method of avoiding the corrosion of copper clad aluminum wire is to apply copper color quick-drying paint: dry within two minutes, and the color is appropriate to the copper. This is very convenient for users who use copper-clad aluminum wire. Because the user can cut the wiring at any part, the broken end must be exposed to the air. In order to avoid electrochemical corrosion after prolonged exposure, the end can be immediately coated with quick-drying paint. The copper and aluminum of the copper-clad aluminum wire cross-section are directly touched. If there is an electrolyte on the surface, there will be electrochemical corrosion. If the copper-clad aluminum wire is placed indoors for a long time and the indoor humidity is not high, electrochemical corrosion will not occur. If it is exposed outdoors, it will not be too severe because the end of the corrosive substance will cover the corrosion appearance. Under the circumstances, significant corrosion will occur.

   When the copper clad aluminum wire is connected, the touch resistance decreases with the increase of the touch load, and then tends to remain unchanged. Because the appearance of aluminum is easy to oxidize, when the load decreases, the touch resistance of aluminum/aluminum and aluminum/copper is larger, and as the load increases, the touch resistance decreases. When copper/copper and copper-clad aluminum/copper-clad aluminum are connected, the touch resistance is small, and the two are very close. This is also an important reason why copper clad aluminum replaces aluminum.

That's all tips, if you want to know more information, click link: