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Brittle gold


#1

I have experienced a number of brittle pieces of 14k gold over the
years. Could it have been caused by exposer to chlorine or seawater?
I have heard that both will cause a reaction with the base metals
causing 14k gold to be brittle. I can’t tell you where or from whom
I heard this maybe someone out there in orchid land has more info.


#2
Could it have been caused by exposer to chlorine or seawater? 

Chlorine in any form…,Chlorox handiwipes, laundry, or swimmimng
pools, etc. will break down alloys in white gold particularly,
making them brittle. Hoover and Strong Refiners wote a newsletter
about this not too long ago. And recommended platinum for all white
prongs. Thomas


#3

There are two things in this world that will dissolve gold - one is
cyanide, and the other is chlorine, whether it be free or in
solution. Someone brought me a ring once that had been lodged in a
drain-trap for some years, and it was all eaten away and corroded…
BTW, when you make aqua regia, the combination
creates certain chlorine ions-that’s why one of the acids is
hydrochloric.


#4
 Chlorine in any form..,,Chlorox handiwipes, laundry, or swimmimng
pools, etc. will break down alloys in white gold particularly, 

Nickel based white golds. The palladium white golds don’t have the
problem.

Peter


#5

The brittleness of gold relates largely to its composition,
manufacturing treatment and the stuff it is exposed to later.

A few years ago there were a lot of problems with ‘red gold’ chains
(ie gold with a lot of copper) and some of these could crumble like
cookies. Zinc (as in many lower Karat and white golds) can also
contribute to brittleness. Different alloys require very different
treatments during manufacture to avoid brittleness problems and also
later application of heat, such as in soldering, can affect certain
alloys unless suitable procedures are used. Care also has to be taken
to avoid exposure to agents or conditions likely to attack some gold
alloys (such as chlorinated swimming pool water or ultrasonic
cleaning tanks).

Manufactures will often produce a wide range of gold alloys, some
suitable for casting, some for hand working and so on. Anyone
working with gold should be aware of at least the basics of gold
alloy characteristics. Jewelers can’t just assume that gold is gold
is gold and that various compositions can used interchangeably.
Recycling scrap gold can also be problematic, not just because of the
varied nature of the scrap gold but because of potential contaminents
such as lead (e.g. from solder)where only a minute amount can cause
terrible brittleness problems. Remember, as with the Orchid
discussion on sterling silver alloys - 18 karat just means that the
alloy contains 75% gold by weight,the other 25% can, in theory, be
any other metal, from aluminium to zinc.

So buy the right gold alloy for the job or make up your own from
pure ingredients.

… but if you have to repair or appraise a customer’s piece and
have no idea what the composition is take care, explain potential
problems to your customer and try to ascertain the nature of the
alloy as best you can - and use a loupe or microscope to look for
cracks or other obvious existing defects (and check again before you
return the piece to your customer). Many of the crumbling red gold
chains only came to light when jewelers later tried to repair broken
links or even just popped them into the ultrasonic cleaner prior to
appraisal.

Clearer disclosure and labelling of gold alloys by jewelery
manufacturers - perhaps a simple international code - would be a
considerable service to the industry and to the consumer.

Good luck to all,
Jack Ogden


#6
There are two things in this world that will dissolve gold - one
is cyanide, and the other is chlorine," Four actually. 

One is “aqua regia” (for more info see
Http://www.encyclopedia.com/html/a1/aquaregi.asp) And the other is
mercury - a bit of a cheat this as it’s technically an amalgam -
slightly different to a solution.

Tony Konrath
Key West Florida 33040


#7
     Short ending:  we repaired all three cracked areas -
including the original - with medium solder.  But the question is,
was it just work hardening and stress cracking, or was there an
alloy issue as well? 

Dear Les, It makes me wonder if this lady had been a nurse during the
50 years that the ring had been on her finger. I have seen things
that resemble what you described after a ring has been exposed to
mercury. When a gold alloy is exposed to mercury, the mercury tends
to migrate deep into the metal. The normal way to repair this is to
heat the entire ring above the vapor temperature of mercury under
"extreme" ventialtion. If it has been exposed and a repair had been
attempted heating the ring until the mercury had “boiled” off then
the surface could appear yellow once more. The inside however could
still be an amalgam. Residual mercury can make the ring brittle as
well as can age or case hardening. The part that you described as
"the body metal began to collapse as well.", would either make me
think that 1. you were using too hot and too small of a flame (which
I doubt), 2. The solder you were using had a higher melting
temperature than the original band alloy, or 3. the metal contained a
contaminant that greatly altered the liquidous temperature of the
alloy. Mercury tends to make an alloy mushy and under the stress
conditions of “flushing up the ends”, it might appear to collapse.
Interesting.

Best Regards,
J. Tyler Teague
JETT Research


#8
       There are two things in this world that will dissolve gold
- one is cyanide, and the other is chlorine," Four actually. One is
"aqua regia" (for more info see 

And aqua regia is really just an extension of the "chlorine"
concept. The gold is converted to gold chloride in solutions by the
action of the acid…

Peter


#9

“Not surprisingly, gold is at the top of the series indicating its
high corrosion resistance. In practise, it is corroded only by a
mixture of nitric and hydrochloric acid (aqua regia). In everyday use
gold does not tarnish. Gold only dissolves in cyanide.” Courtesy World
Gold Council

"Reaction of gold with air Gold metal is stable in air under normal
conditions. However gold does dissolve in aqueous cyanide solutions in
the presence of air.

Reaction of gold with water Gold does not react with water.

Reaction of gold with the halogens Gold metal reacts with chlorine,
Cl2, or bromine, Br2, to form the trihalides gold(III) chloride,
AuCl3, or gold(III) bromide, AuBr3, respectively. On the other hand,
gold metal reacts with iodine, I2, to form the monohalide gold(I)
chloride, AuI.

2Au(s) + 3Cl2(g)  2AuCl3(s)

2Au(s) + 3Br2(g)  2AuBr3(s)

2Au(s) + I2(g)  2AuI(s)

Reaction of gold with acids Gold metal dissolves in aqua regia, a
mixture of hydrochloric acid, HCl, and concentrated nitric acid, HNO3,
in a 3:1 ratio. The name aqua regia was coined by alchemists because
of its ability to dissolve gold - the “king of metals”.

Reaction of gold with bases Gold does not react with aqueous bases."
Courtesy Webelements