# PGM's on Memory sticks?



## cleanbucket1 (Jan 15, 2012)

Hello, This may or may not have been mentioned on here in referance to my question but I cant find the answere. I have googled it and been told by several differant people several differant things in regards to the grey/silver fingers/pins you find on random memory sticks. I have not worked with recovery or refining of any PGM's. Dont really plan on it except for maybe silver. 
SO, Ive been told this metal is silver or tin or platinum or palladium....
Me being big in the precious metal dept., I would assume by the color alone that its palladium but heck, your the experts on such PM's. Please let me know so I know whether these fingers are worth saving or not. Thanks


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## jimdoc (Jan 15, 2012)

Its tin, but they usually sell for the same price as the gold fingered ones.

Jim


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## kurt (Jan 15, 2012)

I am not sure as of yet but I doubt tin (maybe a few) A while back I put about 90 of the so called "tined" ram in HCL to depopulate them of chips, caps, & resistors. While the HCL did a fine job of removing the solder it did not remove the plating from the vast majority. There are only a few(very few) that have the plating removed exposing the copper.

The plating on some have a dull finish to them after the HCL but when you rub then with fine steel wool they show a clear silver colored plating yet. - I suspect these are silver plated with the silver tarnished by the HCL

Others have hardly no tarnish that is easly rubed off with your thumb revealing a bright silvery shine - I suspect these are Pd plated

Nickle could be a possability ?

If they were tin I would think the "thin" plating of tin would have dissolved in the HCL long before the solder mass holding the other components (chips, caps, & resistors) on the board

Kurt


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## kurt (Jan 15, 2012)

Ok - processed the 87 RAM sticks I had today - I was wrong - no values  certainly not worth time & chems

I find it some what interesting & puzzling that the HCL removed the solder but not the plating on the fingers :?: 

Kurt


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## Smack (Jan 15, 2012)

What exactly was it you were hoping to get with just Hydrochloric Acid?


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## philddreamer (Jan 15, 2012)

Kurt, did you also process the black chips?

Phil


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## kurt (Jan 15, 2012)

A while back I used HCL to depopulate the Ram sticks of Chips, caps & resistors. (these are "not" the ram with gold plated fingers) The HCL removed the solder but did not effect the silvery colored plating on the fingers so I figured the plating was something other then tin (suspected actual silver &/or PD) 

So I just processed the the fingers in nitric & got a cloudy blue solution - the blue of course is from the copper & the cloudy I assume is tin (tin paste) There are no values indicated by stannuos test or cementing with copper.

the cloudy in the solution could be silver chloride from residue from the HCL used to depopulate but I washed them really good & they have been sitting dry for about 6 months now.

So if the plating is tin (as Jim said) why didn't the HCL remove it when depopulating?

Or if it is silver turning to a chloride in the nitric because of HCL residue - it's not enough to pay for time & chems.

If there are any PGMs it's not enough to show on a stannous test so again not worth the time & chems.

cleanbucket1 asked the question - I had 87 depopulated sticks so thought I would run then to see.

Kurt


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## kurt (Jan 15, 2012)

philddreamer said:


> Kurt, did you also process the black chips?
> 
> Phil



No - they have been added to other chips & will be processed with other chips so won't be able to give yeald results. Sorry 

Kurt


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## Geo (Jan 15, 2012)

hcl would still be present.it wouldnt take much to make silver chloride.when hcl dries it creates clorine salt so when you put them back into solution any silver would have converted to silver chloride.


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## cleanbucket1 (Jan 16, 2012)

Kurt, 

I thank you for your time and information. This is a big help and a real time saver. Yet, like you im stumped on why the HCL will not deplete the tin????? I also did a test with just the fingers and did a stan. chloride test to find the same thing. I just cant figure out why the so called "tin" would have such a tarnish portraying itself to be just that of Palladium. Beets me :?: .
I really do apreciate your time kurt. Let others say what they want, you know what your doing.


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## philddreamer (Jan 16, 2012)

Thanks Kurt!

I just remembered I have a couple of those type of sticks, so I put a drop of JSP silver testing solution on the fingers & the reaction was a bit of light green, then it turned black. I wiped it out with a paper towel & the was a bit of blackpowder on the towel & the surface of the fingers turned black.
Could that be a sign of some PGM's?

Phil


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## 27182 (Jan 16, 2012)

kurt said:


> ...So if the plating is tin (as Jim said) why didn't the HCL remove it when depopulating?...Kurt



Conformal coating perhaps? Some "conformal coatings" are obvious because they look like a urethane varnish (shiny). But others aren't easy to see. Most of these "invisible" coatings have a dye in them that can be seen under UV / blacklight. Expect to see conformal coatings on newer (RoHS approved electronics) as they can help control the growth of tin whiskers which happens more frequently in lead-free solder.


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## Geo (Jan 16, 2012)

any coating would be a detriment to the contact point i would think.it needs to be bare metal to insure contact.


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## joem (Jan 16, 2012)

philddreamer said:


> Thanks Kurt!
> 
> I just remembered I have a couple of those type of sticks, so I put a drop of JSP silver testing solution on the fingers & the reaction was a bit of light green, then it turned black. I wiped it out with a paper towel & the was a bit of blackpowder on the towel & the surface of the fingers turned black.
> Could that be a sign of some PGM's?
> ...



Could they be tin over copper or
Could they be silver over copper?
Could A/P dissolve the copper underneath leaving a silver coloured foil to be tested.


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## cleanbucket1 (Jan 16, 2012)

Im sitting here thinking about this and all I can do is laugh. Its crazy how most of us know what the micro inches are in most of the items we do recovery on, but none of us know YET, what this funny looking metal is on these fingers. 
Seriously, have not yet been able to do a true test myself, but if anyone has any 90% or better palladium laying around that has some oxidation or can oxidize it on their own, check and compare the color of that on the palladium and that on the fingers to said such memory sticks. Does anyone see a similarity?
Im saying the plating is palladium til research shows differant. :lol:


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## patnor1011 (Jan 16, 2012)

cleanbucket1 said:


> Im sitting here thinking about this and all I can do is laugh. Its crazy how most of us know what the micro inches are in most of the items we do recovery on, but none of us know YET, what this funny looking metal is on these fingers.
> Seriously, have not yet been able to do a true test myself, but if anyone has any 90% or better palladium laying around that has some oxidation or can oxidize it on their own, check and compare the color of that on the palladium and that on the fingers to said such memory sticks. Does anyone see a similarity?
> Im saying the plating is palladium til research shows differant. :lol:



Im saying the plating is tin till testing shows different. :lol: 

You want easy hilly billy test? Take piece of paper. Rub your tin plated finger on that paper - say try your signature. If it leaves grey strike - it is tin. I had hundreds of them, tested a lot of them with stannous, schwerter`s, dmg. I did not find anything. My friend scanned lot of them with handheld X-ray and he did not find any pd or ag plating. 
The reason why they sell the same as gold plated ram is that value is locked inside in chips, not on fingers.


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## philddreamer (Jan 16, 2012)

"The reason why they sell the same as gold plated ram is that value is locked inside in chips, not on fingers."

Pat, you just answered my question before I asked it! :mrgreen: 

Thanks!

Phil


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## kurt (Jan 17, 2012)

Well I am convinced after running the ones I had that there is no value there - or so little its not worth going after,

The part that still has me stumped is if its tin why doesn't the HCL remove it when used to depopulate them - although a conformal coating as suggested by 27182 would be one explaination.

Kurt


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## maynman1751 (Nov 12, 2014)

Digging up an old post here. OK, it's been proven that the silver colored plating IS tin. Do the chips have the same values, by weight, as the gold plated finger ram? Has anyone processed these chips for yields? Patnor, where are you????? :lol:


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## Anonymous (Nov 12, 2014)

maynman1751 said:


> Digging up an old post here. OK, it's been proven that the silver colored plating IS tin. Do the chips have the same values, by weight, as the gold plated finger ram? Has anyone processed these chips for yields? Patnor, where are you????? :lol:



Nowhere near the same value by weight Sir.


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## g_axelsson (Nov 12, 2014)

Everyone is talking about tin, but it should be solder. 60% tin, 40% lead. In the border zone between solder and copper it would create a lot of different alloys between copper, tin and lead. No wonder that hydrochloric acid has a hard time to dissolve all the solder.

And I agree with everyone that says that the value is in the chips only.

Any talk about conformal coating is just wrong, it would create a good isolating surface and you wouldn't get any electrical contact, kind of contradicts what is sought after, a good electrical contact to conduct the signals between the CPU and the memory.

Göran


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## patnor1011 (Nov 15, 2014)

kurt said:


> Well I am convinced after running the ones I had that there is no value there - or so little its not worth going after,
> 
> The part that still has me stumped is if its tin why doesn't the HCL remove it when used to depopulate them - although a conformal coating as suggested by 27182 would be one explaination.
> 
> Kurt



Maybe you seen Nickel under dissolved Tin? Just a thought.


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## patnor1011 (Nov 15, 2014)

maynman1751 said:


> Digging up an old post here. OK, it's been proven that the silver colored plating IS tin. Do the chips have the same values, by weight, as the gold plated finger ram? Has anyone processed these chips for yields? Patnor, where are you????? :lol:



I processed them and quite a lot of them. Yield? That is a tough one to answer. There is simply too many of different types. Various thickness, internal construction and sizes will throw off any estimation. I got everything from 0.8 (that was smallest yield I got) to 2.5 g from kg of them.
I have seen some IC which I got still in manufacturers packaging that they do contain Ag/Pg solder in them. The one I recall without going after notes were IC called Rabbit.


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## g_axelsson (Nov 15, 2014)

There is no reason to nickel plate copper if you cover it up with solder. It would create a weaker connection to the copper beneath and increase the risk of a bad electrical connection.

The lead in the solder will soon saturate the solution (5g led chloride / liter) and creating a crust instead.

Göran


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## maynman1751 (Nov 23, 2014)

Thank You everyone for your answers to my question. 8)


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