The Difference Between ENIG PCB and Gold-plating PCB
There are several processes on the PCB surface finish: HASL (or lead-free), OSP, ENIG, and Gold-plating, etc. Herein, we briefly introduce the difference between gold-plating and ENIG process.
ENIG is a chemical deposition methods, generated by the method of chemical oxidation reduction reactions a coating layer, the general thickness is thick, is a kind of chemical nickel gold layer deposition method, can achieve a thicker gold layer.
Gold plating uses the principle of electrolysis, also known as electroplating. Other metal surface treatments are also mostly used for electroplating.
Due to different crystal structure for ENIG and gold-plating, the gold thickness of ENIG is much thicker than gold plating, the color is golden, more yellow than gold-plating, and gold-plating is slightly pale (due to include nickel); and it is easier to weld for ENIG than gold plating, not to cause welding unqualified. It is also because ENIG is softer than the gold plating, so the ENIG does not wear the gold finger (the defect side of the gold plate).
The ENIG crystals are more dense than gold-plating, so ENIG is less prone to oxidation.
Because ENIG PCB only has nickel gold on the solder pads, the resistance welding for the line and copper layer is much stronger. The transmission of signals in the skin effect is in the copper layer, which does not affect the signal quality. Also it's not easy to make a gold wire short circuit.
The flatness of the ENIG PCB is better than the gold-plating PCB.
To sum up, compared with gold plating process, ENIG process has strong conductivity, good oxidation resistance, long service life, and many other advantages. But because of the ENIG process is more expensive than gold plating process, there are still a lot of low-priced products using gold plating process.
Identification of gold-plating and ENIG:
Gold plating PCB contains nickel, so it is magnetic, which can be used to attract the PCB board with magnet, the one is attracted is gold-plating PCB, and not attracted is ENIG.
Another method, as color also has difference, heavy gold is golder, while for gold-plating when plating is very thin, the plating area is large and tend to be white. When plating is thick also a golden color, it is difficult to distinguish the pads, then using a knife scraping the solder mask, leaking copper layer, because gold-plating process is plating whole PCB board, it is gold nickel copper laminated under the green SM, so it looks golden yellow, but the lamination of ENIG process is in a different way, it's copper under the green SM, so show in red color (red copper).We are one of the leading China manufacturers focusing on FR4 PCB fabrication. If you are interested in our ENIG PCB, welcome to contact our factory. We're sure to offer you the best quality products on time and excellent one-stop service.