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Count the colors of those PCB boards
2021-09-07
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Author:Aure

Count the colors of those PCB boards

PCB is an important core component of electronic equipment and is known as the "mother of electronic products". On PCB boards, we often see some precious metals. The colors of these precious metals are mainly three types: gold, silver, and light red. According to the production price, from high to low, gold is the most expensive, silver is the second most expensive, and light red is the cheapest. Today we will learn about the colors of those PCB boards:

      First of all, we have to understand a question: how do the precious metals on the PCB come from?

      The surface of the PCB board needs to be soldered with components, which requires that a part of the copper layer must be exposed to the outside for soldering. These exposed copper layers are called pads. After the solder mask is applied, the copper on the pads is exposed to the air.


Count the colors of those PCB boards

      These exposed copper layers need to be protected to prevent oxidation; if the copper is oxidized, it will not only affect the welding quality, but also increase the resistivity, which will seriously affect the performance of the product. Therefore, in order to protect the copper layer from being oxidized, PCB manufacturers will coat the pad with inert metal gold, or cover the surface with a layer of silver through a chemical process, or cover the copper layer with a special chemical film to prevent oxidation and protect the pad. , Improve the welding quality and ensure the yield rate.

1. PCB copper clad laminate

      Copper clad laminate is a plate-shaped material made by impregnating glass fiber cloth or other reinforcing materials with resin on one or both sides, covering with copper foil and hot pressing.

      Copper clad laminate is the basic material of printed circuit board; and printed circuit board is an indispensable main component for most electronic products to achieve circuit interconnection. The conductors used in printed circuit boards are generally made of thin foil-shaped refined copper, that is, copper foil in a narrow sense.

2. PCB gold-plated (immersion gold) circuit board

      Direct contact between gold and copper will cause electron migration and diffusion, so it is necessary to electroplate a layer of "nickel" as a barrier layer, and then electroplate gold on top of the nickel, which is called electroplating gold or "electroplating nickel gold".

      Immersion gold is a chemical reaction that crystallizes gold particles and adheres to the PCB pads. Because of the weak adhesion, it is also called soft gold. In the PCB process, both electroplating of nickel and gold and immersion gold belong to the surface treatment process. The difference is that the electroplating of nickel and gold is done before the solder mask; while the immersion gold is done after the solder mask.

3. PCB Immersion Silver Circuit Board

      The production price of Immersion Silver is cheaper than gold plating and Immersion Gold, and it has good flatness and contact. If PCB needs to reduce costs, Immersion Silver must be an ideal choice.

Immersion silver is widely used in communications, automobiles, computers and other fields; due to its excellent electrical properties that other surface treatments cannot match, the Immersion Silver process is also widely used in high-frequency signals.

Through the introduction of precious metals and their colors on the PCB, I believe everyone must have gained knowledge! The production of PCB is a real "ingenuity project", complicated and meticulous. Different colors on the PCB represent different surface treatment processes. Hope the above introduction can help everyone.