PM in 3-legs transistor , gold and silver?

Dear all ,
I cut in half a black transistor in a old Phillips TV and I have found a gold plated layer (no gold bonding wires apparently) underneath the silicon die and a metallic plating over the 3 metallic terminals (see the picture below), could it be silver?

Thanks for your attention, have a good day!

Test it! Just put a drop of nitric on it. If it does not dissolve add a drop of HCL. If that dissolves it, it's probably gold. And then test with stannous to confirm.

Btw, i missed your update last month.
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=29654&p=312499#p312365
Nice job on the washing!
The experience gained is so much more worth than that bit of gold. It almost looks like you panned some placer gold in that beaker :lol:
I have to comment on some of your pictures though. Please wear gloves when handling beakers and toxic chemicals. Your skin is a great absorber for that stuff. Stay alive long enough to enjoy your gold.

Martijn.

Thanks Martijn for your reply

"Test it! Just put a drop of nitric on it. If it does not dissolve add a drop of HCL. If that dissolves it, it's probably gold. And then test with stannous to confirm."

unfortunately i have no access to Nitric, could i use HCl or AP to obtain AgCl and then expose it to sunlight?

"Btw, i missed your update last month.
Nice job on the washing!
The experience gained is so much more worth than that bit of gold. It almost looks like you panned some placer gold in that beaker "

thank you very much , absolutely, i really had a lot of fun to learn and passing through all the steps necessary to obtain that powder. Next step: panning the gold from powders obtained from IC chips. It has been a very good workout for triceps and shoulders but tough experience for my hands !

" Please wear gloves when handling beakers and toxic chemicals. Your skin is a great absorber for that stuff. Stay alive long enough to enjoy your gold."

you are absolutely right, i wear gloves when i pour liquids in and out the beakers and during the filtration stage, but i should keep them too when i take the snapshots even if i had less grip on the objects and the touchscreen does not work properly. Thank you again, have a good weekend!

One glove for the beaker, or a stand or a clamp if slippery, one hand without glove for the camera
If i may suggest :wink:

And in stead of nitric to test for base metals and low carat, you can go for HCL & bleach to dissolve some of the gold, then test with stannous to confirm.

Gold plating is usually there for a reason. 'Thick' plating for contact points that see a lot of ebrasive movement. Thinner for once or twice in a lifetime changed out components, atoms thick (read negligible) for corrosion protection plating ENIG.
And plating to ensure good thermal and electric conductivity. Which this one is i guess. I think the thickness will be on the thin side of this spectrum.

Sure, Thank you, suggestions are always welcome
Looking well (with aid of solar light ) the terminals are definitely gold plated and I found a very small amount of gold powder after I pulverized some of them (see pictures). They have very tiny and short gold bonding wires.




Have a good day!

We have processed quite a lot of these (roughly 800kgs). 50% by weight will be copper after thorough incineration. Gold value is between 0.10-0.15 grams per kg of these 3 legged transistors. Hope this helps !