I bought some “silver” electrical contacts. These are fairly large rectangular and square pieces.
I weighed them out and calculated the amount of dilute nitric needed to reduce the lot. I placed some (3 or 4 pieces) in 50/50 nitric/distilled my water solution (580ccs each) and heated the bath. I only add a few at a time to prevent an over run reaction. I got an almost instantaneous reaction, as expected, however it lasted a few minutes. Then the reaction completely stopped! Leaving large intact pieces.
So to me it sounds like there was a silver coating on some other metal. Any clues?
Most contacts are made of:
Gold
Silver
Nickel
Palladium
Platinum
Copper
Graphite
Copper/chromium
Silver tungsten
Out of that list, The only things I can think of are chromium or platinum. Gold would be observable, nickel palladium and copper would have dissolved, tungsten would have continued to react but slowly and graphite is brittle. These are definitely heavier than graphite and cut like metal. The pieces are non-ferrous. How can I tell what they are?
If they are platinum, why would they silver plate them? Obviously if they are platinum I would like to recover.
however if they are chromium IDK if there is value there. If they are copper chromium it would seem the reaction would have continued.
Any ideas?
I weighed them out and calculated the amount of dilute nitric needed to reduce the lot. I placed some (3 or 4 pieces) in 50/50 nitric/distilled my water solution (580ccs each) and heated the bath. I only add a few at a time to prevent an over run reaction. I got an almost instantaneous reaction, as expected, however it lasted a few minutes. Then the reaction completely stopped! Leaving large intact pieces.
So to me it sounds like there was a silver coating on some other metal. Any clues?
Most contacts are made of:
Gold
Silver
Nickel
Palladium
Platinum
Copper
Graphite
Copper/chromium
Silver tungsten
Out of that list, The only things I can think of are chromium or platinum. Gold would be observable, nickel palladium and copper would have dissolved, tungsten would have continued to react but slowly and graphite is brittle. These are definitely heavier than graphite and cut like metal. The pieces are non-ferrous. How can I tell what they are?
If they are platinum, why would they silver plate them? Obviously if they are platinum I would like to recover.
however if they are chromium IDK if there is value there. If they are copper chromium it would seem the reaction would have continued.
Any ideas?
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