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 Replies: 43 / Views: 12,474 |
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Pillar of the Community
United States
1796 Posts |
Quote:
That is a function more dependent on the instrument itself, and not the analytical technique. How powerful was the beam on the instrument you used, and was the detector and instrument calibrated to handle analysis of alloy metals? I use an INNOV-X X-5000 Series Bench Top Instrument, with a 10 Watt X-ray tube, 50 keV, 200 μA (max) and a silicon drift detector. I have penetrated platings that I know were well in excess of 100 microns thick... I wasn't the one who analyzed it, the previous owner was, so I'm honestly not sure what the specs on their equipment were. I'll see about asking them. Quote:
See my earlier note, about being able to penetrate right through oxidized surfaces - I can provide published literature on the topic, if necessary. Aye, but it's not just a case of oxidization. The oxidization would add back the weight removed from nickel-leaching. In any case, the only way to really proceed from here is to crack one of them open like an Oreo and find out. :-) |
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Moderator
 Canada
10463 Posts |
Well, the logical solution is to test this hypothesis. I will take the next "brown" nickel I find that is in excess of 82% copper on my XRF, and then grind off one side until I am well into fresh metal. Then, I will test that freshly ground side and compare the results. That should resolve the issue whether this is surface annealing or a compositional error.
I guess I would pose the question in a reverse engineering fashion. Can anyone here 'create' a brown nickel, by taking a normal, dull grey 75% Copper 25% Nickel and leaching it to create a surface of more than 82% copper?
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Pillar of the Community
United States
2739 Posts |
I haven't subjected any improperly annealed 5 cent errors to XRF analysis. So I can't comment on whether the surface layer of copper (which can be fairly thick) can add 8 percentage points to the normal 75% copper fraction. I'm merely saying that the coin's appearance is similar to other improper annealing errors. Here is a useful summary of the phenomenon: http://www.error-ref.com/improper-annealing.htmlError coin writer and researcher.
Edited by mikediamond
01/25/2013 12:15 am
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Moderator
Canada
10463 Posts |
The sacrificial lamb, a dateless brown Buffalo nickel, that tested 82% copper on the XRF. Oh, the sacrifices one must make, for science. Before pics:   The coin spent three days in a light vinegar bath, to remove any surface impurities.  Then, the reverse met its untimely end, care of my axe file, until a majority of the surface was bare, fresh metal. Then a quick acetone wash.  I will test both sides with the XRF sometime this week, stay tuned. "Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Pillar of the Community
United States
1796 Posts |
 The things we must do for science.  Edited by SteveCaruso
01/28/2013 6:32 pm
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Moderator
 United States
56855 Posts |
 John1  PS, Have you had a chance to mail out my coin yet SPP-Ottawa? Edited by John1
01/28/2013 7:05 pm
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Moderator
Canada
10463 Posts |
You bet - posted Friday.
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Moderator
United States
56855 Posts |
Thanks much Roger,I am waiting on pins & needles  John1 |
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Pillar of the Community
United States
621 Posts |
I know this is a kind of old thread but I have to ask/know how the testing of the shaved buffalo turned out if you were able to test it.
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Moderator
United States
56855 Posts |
justin3651, You should PM the person who did the testing. John1 |
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Moderator
Canada
10463 Posts |
Rather surprising results... Something I intend to publish later this year...
"Discovery follows discovery, each both raising and answering questions, each ending a long search, and each providing the new instruments for a new search." -- J. Robert OppenheimerContent of this post is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. See: http://creativecommons.org/licenses...0/deed.en_USMy eBay store
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Bedrock of the Community
United States
62064 Posts |
75% copper is normal. 25% nickel.
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Pillar of the Community
United States
621 Posts |
"Rather surprising results... Something I intend to publish later this year..." You sir are killing me   . Approximately how long till it comes out do you think? where will you release it on? this subject is one that's really interesting to me.  |
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Valued Member
United States
360 Posts |
"We have concluded that the damaged buffalo has now risen from the coin, and has decided to go back into nature where he belongs."
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Pillar of the Community
United States
2624 Posts |
SPP-Ottawa: Please alert us when you publish,include where I can get a copy.
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Posted 01/24/2013 8:53 pm
