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What is the difference between gold and silver plating on PCB?

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The main difference between gold and silver plating on PCB is reflected in the following aspects:

Material and Performance:  Gold plating is a thin layer of gold covering the PCB surface, the main role is to improve the conductivity of the PCB, corrosion resistance and prevent oxidation. Silver plating is a thin layer of silver covering the surface of the PCB, the main role is to improve the conductivity and heat resistance of the PCB.

Color:  The color of gold plating is bright yellow, while the color of silver plating is off-white or dark gray.

Applications: Gold plating is usually used in electronic products that require high quality and reliability, such as high-speed transmission and mass storage devices. And silver plating is usually used to meet the high temperature requirements of the occasion, such as high-power LED lights.

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There are significant differences between gold and silver PCB plating in terms of material, performance, color and application. The choice of plating depends on the specific application needs and design requirements.

PCB surfaces need to be soldered to components, which requires a portion of the copper layer to be exposed for soldering. These exposed copper layers are called pads, which are generally rectangular or round in shape and small in size.

If the copper on the pad is oxidized, not only is it difficult to weld, but also the resistivity increases greatly, seriously affecting the end product performance. Therefore, engineers have come up with a variety of ways to protect the pad. For example, plated with inert metal gold, or on the surface through a chemical process to cover a layer of silver, or a special chemical film to cover the copper layer, to stop the pad and air contact.

The exposed pads on the PCB have the copper layer directly exposed. This part needs to be protected to stop it being oxidized.

From this point of view, whether it is gold or silver, the purpose of the process itself is to stop it from being oxidized and to protect the pad so that it ensures yields in the soldering process that follows.

However, the use of different metals will put requirements on the storage time and storage conditions of PCBs used in production factories. Therefore, the PCB factory will generally be completed in the production of PCB, delivered to the customer before use, the use of vacuum plastic sealing machine packaging PCB, the limit to ensure that the PCB does not occur oxidation damage.

And in the components on the machine before welding, board manufacturers also want to detect the degree of oxidation of the PCB, remove the oxidized PCB, to ensure that the yield rate. The final consumer to get the board, is already over a variety of tests, even after prolonged use of oxidation will almost only occur in the plug connection parts, and on the pads and components have been welded, there is no effect.

Because of the lower resistance of silver and gold, then the use of silver and gold and other special metals, will not reduce the PCB heat when used?

We know that the factor that affects heat generation is resistance; resistance is in turn related to the material of the conductor itself, the cross-sectional area and length of the conductor. Pad surface metal material thickness is even far less than 0.01 millimeters, if the OST (organic protective film) way to deal with the pad, there will be no excess thickness. The resistance of such a small thickness is almost 0, even impossible to calculate, of course, will not affect the heat generation.

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