What is the reason why the wire sometimes turns black after being coated with tin

What is the reason why the wire sometimes turns black after being coated with tin

Why does wire peeling and tin staining cause oxidation blackening? Many people believe that it is a climate issue, possibly due to the weather being too cold, too hot or too high, etc. After multiple practical verifications and improvements, it has been found that climate issue is only one of the influencing factors, but this factor can be effectively controlled.

Untreated copper wire or tinned copper wire can also oxidize without tin. Copper is oxidized in two steps in air, first reacting with oxygen to produce copper oxide; Then copper oxide reacts with carbon dioxide and water in the air to generate green copper rust. Copper oxidation is a normal chemical reaction, and the higher the humidity in the weather, the more water droplets will attach to the surface of the product. The less air is circulated or the lower the temperature, the more difficult it is for the surface water droplets to evaporate, thereby accelerating the oxidation reaction between copper and air, causing the tin on the electronic wire to turn black.

Another situation is when soldering flux is used during soldering, and when soldering is heated, the flux will enter the wire copper wire, causing slight oxidation and blackening of the wire, which is also a common situation. So, will the blackening of copper wire caused by tin contamination affect its use? The answer is that it does not affect use, as long as the outer skin of the wire is intact and undamaged, and slight oxidation of the copper wire does not affect use.

So the most suitable method to solve the problem of tin on electronic lines is to use vacuum and isolation technology. By using isolation film forming technology, a completely transparent layer can be formed outside the tin points of the product, and it can be completely decomposed after high temperature. This isolation film forming technology can enable the product to resist oxidation for up to a year. In fact, nickel and gold plating on products also use this technology.