Gold plated OR Silver plated

[tony_lth]

Hi, Gurus,
Amphenol provided me a option for the same connector as U.FL-LP-066, one is gold plated and the other is silver plated.
I used them in GSM 900M. And hope the coonector life the longer, the better.
I don't the difference of the gold-plated or silver plated, any comment？
Many thanks.
Best,
Tony Liu

 

[tony_lth]

From Amphenol technical support, there is little difference between gold-plated and silver-plated.
Thanks.

 

[vfone]

Yes, there is little difference between gold and silver plated. Sometimes gold is preferred because is a bit more durable in time.

 

[jesuschrist]

There is a little difference and it comes from skin depth and conductivity. For 10 GHz gold has 24.8 micrometers skin depth while silver has 20 micrometers.Also silver has higher conductivity than gold, but gold has more chemical resisteance.It's all up to you to choose between.

 

[tony_lth]

Yes, there is little difference between gold and silver plated. Sometimes gold is preferred because is a bit more durable in time.

Hi, vfone,
I originaly doubt the durable time of silver plated, but Amphenol FAE told me they are the same, according to Amphenol test, such as salt-frog etc.
Do you agree it? I doubt it.
Best,
Tony Liu

 

[N.Narayanan]

Generally, gold plating has good tarnish resistance than silver plating. So silver plating life is less than gold plating.
If they added the tarnish protection coating in silver plating then both plating may be have same life.

 

[vfone]

As already confirmed by others, gold plated is more durable than silver plated.
There are many places in electronics (with no skin depth influence) where even simple copper is preferred than using silver plated.

 

[biff44]

Silver is subject to dendritic growth, while gold is not. So if it is used in a moist atmosphere with a DC potential across the pins...you can end up with some odd short circuits happening....

silver DOES tarnish, but the tarnish is also conductive so it is not normally a big deal.
Gold, if it is plated on too thick, can cause soldering embrittlement problems. So it needs to be a "gold flash", and not a thick gold plating, to be reliable.

 

[c_mitra]

While it is true that Ag (silver) corrodes rapidly (yes!) in air, the film is not continuous and the wiping action of the conventional connectors breaks the film. If you are planning to have a large number of connect/ disconnect cycles, use Au (gold) else use Ag (silver). But is important to have the same plating on both sides of the connector else you will develop a potential.

 

[c_mitra]

Silver is subject to dendritic growth ....

True, but.

Dendrites are commonly formed under reducing condition (snowflakes are dendrites) OR during recrystallization. Both Ag and Au alloy well with copper (the substrate metal) and any thick plating (Ag over Cu OR Au over Cu) is thermodynamically unstable. It is possible for Ag to dissolve in the Cu base and recrystallize as dendrites but the chances are small. Gold films are relatively pore free (Au is the most malleable of all metals and Pt is the most ductile) and they have far less tendency to crystallize.

Of course Ag dendrites can form during electrolysis but only if there is a sufficient potential difference. Au surface is not clean (contrary to popular beliefs) but because of the lack of pores, the electrolysis is far more rare. But common solder (Pb-Sn) alloys well with silver but gold is a problem. If Ag is electrochemically deposited, it is best to anneal to get it alloy well with Cu base (that may help reduce dendrites) but this step is not needed for Au. But the common connectors are not pure Cu and all my ramblings may be pure irrelevant.

 

[Azulykit]

The only good thing about a U.FL connector is that it is small and oh yes, cheap. I would be really reluctant to use one at 10 GHz. They also have limited life in terms of mate and break cycles. I have been given estimates form the manufacturer on the order of 6 to 12 cycles. Silver has better conductivity but oxidizes and gold is relatively inert.

Regards,

Azulykit