The potentials of copper and aluminum are different. The part in contact with copper and aluminum will accelerate the oxidation of the aluminum wire due to the reaction of the galvanic battery. If you want to connect them together, you must use a copper-aluminum transition clamp or transition tube.
The chemical properties of metals are relatively active and inactive. For example, gold never rusts. This means that gold is chemically inactive. Iron is prone to rust. Iron is more active than gold. If two metals are put together, it will Accelerate the oxidation of active metals. Compared with copper, aluminum is more active. The connection of the two cables will accelerate the oxidation (that is, rust) of the aluminum wire, which affects the use. You will know more details in iron aluminum alloy
When the copper and aluminum conductors are directly connected, the contact surface of these two metals can easily form an electrolyte under the action of moisture, carbon dioxide and other impurities in the air, thereby forming a primary battery with aluminum as the negative electrode and copper as the positive electrode. , Which causes galvanic corrosion of the aluminum wire, resulting in an increase in the contact resistance at the junction of the copper and aluminum wires.
Since the elastic modulus and thermal expansion coefficient of copper and aluminum are very different, after multiple cooling and heating cycles (power on and off) during operation, a large gap will be generated at the contact point, which will affect the contact and increase Increased contact resistance.
The increase in contact resistance will cause the temperature to rise during operation. Corrosion and oxidation will intensify under high temperature, creating a vicious circle, further deteriorating the quality of the connection, and finally resulting in excessively high contact point temperature and even smoke, burning and other accidents.
For aluminum wire, it is not only a matter of quality to evaluate its quality, but also energy conservation and other considerations. For this kind of wiring harness with a relatively large demand, it is recommended to choose a good quality and more cost-effective, because it will not only last a long time, but also help everyone save a lot of maintenance costs. You may get more details about cafe cored wire.
If you choose poor quality aluminum wire, the probability of problems is still relatively large. Therefore, although the price of a good aluminum wire is high when it is purchased, after a long time of use, you will find that it saves you a lot of maintenance costs.