Why do precision parts turn black after processing copper materials How to deal with it

Why do precision parts turn black after processing copper materials? How to deal with it?

Copper is the main raw material commonly used as industrial processed products from ancient times to the present. It is processed into various complex-shaped stamping products, hardware parts, and military parts product cartridge cases. It has a wide range of daily uses, such as drainage pipes, medals, and medals in daily life. Electrical parts, musical instruments, valves and pipe fittings, etc.

Why does the copper material for precision parts processing become black? Because copper is an active metal atom, it is prone to chemical reactions when it meets oxygen in the air. After most of the metal is oxidized, it will turn black and produce copper oxide. The chemical reaction formula is: 2cu+o2=2cuo

In many cases, the brass parts processed by precision parts are oxidized and blackened before they are sent to the customer. The quality is reduced, the appearance is affected, or even rework is caused, and the cost is increased.

How to deal with it?

At this time, passivation treatment should be done. The principle is to attach a chemical conversion film. Because it is a chemical conversion film, it cannot be touched by hand. It does not affect the conductivity, and the weldability and the hardness of the workpiece size will not change.

The treatment process is as follows: Use a stainless steel container to fill the passivation solution, put the workpiece to be treated and soak for about 5 minutes, take the workpiece out, rinse with water and dry it; note that the workpiece must be pre-treated before passivation , The purpose is to prevent oil stains or oxides on the surface of the workpiece, you need to degreasing or cleaning oxidation first, you can use a cleaning agent or degreasing agent to remove the stains, and then clean the surface for passivation protection. In order to increase the brightness of the parts, you can also use a polishing agent to polish the surface before processing. The polishing process does not require any equipment in the whole process, and you can take a direct immersion method.

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