# Metal resistant to corrosive



## MartinMartinez (Feb 13, 2013)

Hello.

Does there are any Metal that has similar property of Corrosive like Hight purity of Gold 18k, like you know 18 K gold don't dissolve in Nitric Acid or Royal Water(Nitro-hydrochloric acid) that fast like other's(Copper,Iron)

I thing that the Best is Stainless Steel 316 right?

But i wonder if the Tungsten also is resistant to Corrosive.

Thanks!


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## Geo (Feb 13, 2013)

uhh,what? AR will dissolve gold quickly even at cool temperatures, even if its 24K. there are some resistant metals, but AR will attack 316.nitric alone would have some trouble attacking 316 stainless. what are you trying to do? a little more information about what you intend to do may let someone help you decide what you need to use.


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## MartinMartinez (Feb 14, 2013)

Geo said:


> uhh,what? AR will dissolve gold quickly even at cool temperatures, even if its 24K. there are some resistant metals, but AR will attack 316.nitric alone would have some trouble attacking 316 stainless. what are you trying to do? a little more information about what you intend to do may let someone help you decide what you need to use.



I'm not sure about,that AR will dissolve gold of 18K or more that quickly, because the acid test for gold 18K has AR right? In jewerly shop they scratch the Ring or Chain in the stone and add THIS acid to check if it gold 18K,if the acid(AR) dissolve the mark its not 18 K gold.

But I'm not sure if the acid used for Check the gold of 18K has Aqua regia or other Acid.


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## nickvc (Feb 14, 2013)

Geo,s right I'm afraid. Hoke details a process for using dilute cold AR to remove the gold from mixed platinum and gold jewellers filings also 18 karat gold dissolves very well and easily in AR so well that if you doing karat gold refining you can go straight with AR to refine 18 k if you now what your doing. The hydrochloric in the AR will attack the stainless very well and in the testing kits the acid dissolves some of the gold and it's the colour as much as anything that gives your a determination of the karat involved. I fear you have much to learn.


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## bswartzwelder (Feb 14, 2013)

Your questions really indicate a lack of knowledge about precious metals recovery and refining. Download a copy of Hoke's book from this website and start reading. Also, start reading the posts on the website. Nowhere can you get more or better information, and best of all, it's free.


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## Lino1406 (Feb 15, 2013)

Tantalum is most resistant
Titanium practically resistant


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## jonn (Feb 15, 2013)

The scratch test uses nitric, titanium is what you're looking for, after you read Hoke. Can you please share what you're trying to build? Or what you're trying to dissolve? It is much easier to discuss a topic that is clearly understood. Are you looking for an electrode? Please explain so that the proper advice can be given. Welcome to the forum.


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## kurt (Mar 1, 2013)

Read page 65 in Hokes book - 18K & 16K gold are a special case - it's to high in gold for nitric to work (to disolve base metals leaving behind gold) & to high in silver for AR to work (even hot AR) --- you need to inquart it

Kurt


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## kurt (Mar 1, 2013)

Just re-read his question & it looks like he is looking for a metal that is resistant to AR like 18K gold is - not sure why though

Kurt


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## Geo (Mar 1, 2013)

kurt, it really depends on the alloy. if its green gold, AR will have no problem dissolving 18K. it all depends on the contents of the alloy.


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