Difference between Immersion gold and Plating gold.
There are some usual kinds of surface Treatment ,including OSP(Organic Solderability Preservatices) ,HAL(Hot Air Leveling ),Electrolytic Ni/Au ,Immersion Au and so on .
Especially the demand for gold boards is large,the reason is that gold have strong conductivity ,anti-oxidation ,long life , and in factual using ,90% people prefer to immersion Au instead of plating Au .The most fundamental difference is that gold-plated is hard gold (wear-resistant), immersion gold is soft gold (not wear).
Immersion Au is a chemical deposition method, through the chemical redox reaction methos to generate a layer of coating ,generally thicker thickness .
Plating Au is using the principle of elextrolysis ,also known as electroplating mode.
1.Thickness and color of gold.
The gold thickness of immersion is thicker than gold-plated ,and the color is trend to yellow .
2. Solderability
As the stress of the immersion Au is easier to control, which is more advantageous to the processing of the bonding products. Compare to plating Au ,its solderability is much better.
3. Signal Transmission
The immersion gold plate only has the nickel gold on the pad, the skin effect signal transmission is in the copper layer does not have the influence to the signal.
4. Oxidation
The crystal structure is more dense for immersion Au, not easy to produce oxidation.
5. Gold–wire short circuit
The requirement for the processing is more higher like the line width and spacing which is up to 0.1mm, plating Au is easy to be found the gold wire short circuit ,and because of the nickel gold on the pad ,so immersion Au can avoid this phenomenon of short circuit .
6. Smoothness
Immersion Au which generally will not appear after the assembly of the black mat phenomenon. The smoothness of the immersion gold plate and the service life is better than the gold plate.
In a short ,we can get the roughly difference as per below table .
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