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Offline darkkitten2000Topic starter
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« on: March 25, 2009, 05:42:33 am »
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Hello,
i came accross two 14 and 18 carat gold alloy rings (modern origin), one quite large, that cannot be detected by PI detectors (tested several commercial and home made ones), and i do not know how the VLFs would do. The conductivity is rather high, much higher then the same size aluminium ring, detected at good 20 cm. The gold alloy is authentic (verified) but the jewellery company wish not to reveal the alloy comosition.
I cannot understand why there is virtualy no eddy currents. Any idea? (It is a well conductive single loop coil, right?)

d.

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Offline highaltitude
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« Reply #1 on: March 25, 2009, 06:00:21 pm »
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In the NMR field they use alloys of the following materials as coatings to reduce eddy currents in the electromagnets (nickel, iron, cobalt, chromium, molybdenum, copper, and aluminum)  It is possible an alloy of one or some of these metals is either combined in the gold of the ring or coating the ring to help increase surface durability.

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Offline Homefire
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« Reply #2 on: March 25, 2009, 08:28:49 pm »
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I seen a gold/aluminum ring one time that was way to light to be any gold that I know.

That would be hard to detect.

But at 18K it should be just like any other ring.

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Offline highaltitude
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« Reply #3 on: March 25, 2009, 10:41:27 pm »
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18K gold contains 18 parts gold and 6 parts of another metal(s), making it 75% gold.

Color of Gold Alloy Composition

Yellow Gold (22K) Gold 91.67%
Silver 5%
Copper 2%
Zinc 1.33%

Red Gold (18K) Gold 75%
Copper 25%

Rose Gold (18K) Gold 75%
Copper 22.25%
Silver 2.75%

Pink Gold (18K) Gold 75%
Copper 20%
Silver 5%

White Gold (18K) Gold 75%
Platinum or Palladium 25%

White Gold (18K) Gold 75%
Palladium 10%
Nickel 10%
Zinc 5%

Gray-White Gold (18K) Gold 75%
Iron 17%
Copper 8%

Soft Green Gold (18K) Gold 75%
Silver 25%

Light Green Gold (18K) Gold 75%
Copper 23%
Cadmium 2%

Green Gold (18K) Gold 75%
Silver 20%
Copper 5%
 
Deep Green Gold (18K) Gold 75%
Silver 15%
Copper 6%
Cadmium 4%
 
Blue-White or Blue Gold (18K) Gold 75%
Iron 25%
 
Purple Gold Gold 80%
Aluminum 20%

There are other less popular alloys.  As you can see 18k gold can be an alloy of many different things.  Rhodium and other exotic metals are plated on white gold for durability and to enhance the white color








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« Last Edit: March 25, 2009, 10:47:23 pm by highaltitude »
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Offline Sauerkraut
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« Reply #4 on: March 26, 2009, 01:32:59 am »
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I think all Metals and Alloys must have an eddy Current Effect.
It seems like this Gold ring is outside of the PI sampling Window,
it could be in the "early sampling" Area that is needed for tiny Gold Nuggets
or even in the "late sampling" Area that might be used for Ground Balance.

Use a Scope and take a good look at the PI input Signal after the Clamping Diodes.  Teach


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Extraordinary claims require extraordinary evidence.

Offline darkkitten2000Topic starter
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« Reply #5 on: March 26, 2009, 04:56:15 am »
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Clever!


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