PCB Nickel Plating Problems And Troubleshooting Methods

- Oct 24, 2017 -

1 PCB plating burns

Possible causes of plating burns: low boric acid, low metal salt concentration, low operating temperature, too high current density, too high pH or insufficient agitation.

2 PCB deposition rate is low

Low pH or low current density results in low deposition rates.

If the copper coating is not activated by the deoxidized layer, copper and nickel between the adhesion is poor, it will produce coating peeling phenomenon. If the current is interrupted, it may cause the self-peeling of the nickel coating; the temperature is too low and the peeling phenomenon may occur.

3 PCB coating brittle, poor solderability

When the coating is bent or subjected to some degree of wear, it usually reveals the brittleness of the coating, which indicates the presence of organic or heavy metal contamination. Too many additives, so that the coating of organic matter and decomposition products increased, is the main source of organic pollution can be treated with activated carbon; heavy metal impurities can be removed by electrolysis and other methods.

4 PCB coating dark and uneven color

The coating is dark and uneven in color, indicating metal contamination. Because the copper is generally the first nickel plating, so the copper into the solution is the main source of pollution. It is important to minimize the amount of copper solution that is attached to it. In order to remove the metal contamination in the tank, the corrugated steel plate was used as the cathode, and electrolyzed at a current density of 0.12 to 0.50 A / dm2. Poor pretreatment, poor surface coating, current density is too small, the main salt concentration is too low, the conductive contact will affect the coating color.

5 PCB coating foaming or skinning

Poor pretreatment, intermediate power failure time is too long, organic impurities pollution, current density is too large, the temperature is too low, the pH is too high or too low, the impact of impurities will produce serious foaming or skinning phenomenon.

6 PCB anode passivation

Lack of anode activator, anode area is too small current density is too high.

7 PCB mattress (pinhole)

Ma Hang is the result of organic pollution. Large linen usually shows oil pollution. Poor mixing, you can not expel the bubbles, which will form Ma Hang. We can use the wetting agent to reduce its impact, we usually put a small pimple called pinhole, poor pretreatment, metal impurities, boric acid content is too small, the bath temperature is too low will produce pinholes, so the bath maintenance And strict control of the process is the key.

8 PCB Rough (Burr)

Roughness that the solution is dirty, can be corrected by adequate filtration; pH is too high easy to form hydroxide precipitation should be controlled; current density is too high, anode mud and add water impurity into impurities, serious will produce rough (burr ).

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