In PCBA patch processing, PCB circuit board production is a very important link, and there are many process requirements for PCB circuit boards. For example, customers often require gold plating and immersion gold processes, both of which are commonly used in PBC boards. The processing seems to be similar to the name, but in fact there is a big difference. Many customers usually can't distinguish the difference between the two methods of processing. What is the difference between PCB gold plating and immersion gold?

Gold plating: mainly by electroplating, the gold particles are attached to the pcb board. Because gold plating has strong adhesion, it is also called hard gold. The gold finger of the memory stick is hard gold, which has high hardness and wear resistance.

Immersion gold: A layer of plating is generated by a chemical oxidation-reduction reaction method. The gold particles are crystallized and attached to the pads of the pcb. Because of the weak adhesion, it is also called soft gold.

The difference between gold-plated and sinking gold:
1. The gold-plating process is done before the solder mask, and it may appear that the green oil is not cleaned and it is not easy to apply tin; while the immersion gold process is done after the solder mask, and the patch is easy to solder.
2. Before the gold plating process, it is usually necessary to plate a layer of nickel first, and then plate a layer of gold. The metal layer is copper-nickel-gold, because nickel is magnetic and has an effect on electromagnetic shielding. The gold immersion process directly immerses gold on the copper skin, and the metal layer is copper-gold, without nickel, and without magnetic shielding.
3. The process of gold plating and immersion gold is different, and the crystal structure formed is different. Immersion gold is easier to weld than gold plating and will not cause poor welding. In addition, immersion gold has a denser crystal structure than gold plating and is not easy to produce oxidation.
4. The flatness of gold-plated circuit boards is not as good as that of gold-plated boards. For boards with higher requirements, the flatness is better. Immersion gold is generally used. Immersion gold generally does not appear as a black pad after assembly.