Text 30718, 163 rader
Skriven 2009-04-03 09:21:23 av Michiel van der Vlist (2:280/5555)
     Kommentar till en text av Robert Bashe (2:2448/44)
Ärende: Gold
============
Hello Robert,

On Wednesday April 01 2009 16:40, you wrote to me:

 MV>>>> Neither diamond nor gold have much intrinsic value. Both have
 MV>>>> limited application in industry and both are not irriplaceable.

 RB>>> Not true, as gold does not corrode

 MV>> It dissolves in "Kings water".

 RB> Nice joke. What doesn't?

Carbon?

Which is also a good conductor (heat and electricity).

IIRC glass does not dissolve in Kings water either. Where else does one store
it?

 MV>> Yes, it is very corrosion resitant. But so is stainless steel...

 RB> Yeah, the Russians liked to make tooth crowns out of stainless. But
 RB> it's hard to work and is definitely NOT as chemically neutral as gold.

True. But it is good enough for most application. One of the exceptions is use
inside the human body. Titanium is better suited for that. It is inert to boody
fluids and its tensile strength is better than steel. FAR better than gold.

 RB>>> and is highly conductive (heat and electricity),

 MV>> Actually its electric conductance is LESS than that of copper.
 MV>> (45.2 x 10^6 S/m2 vs 59.6). Silver is slighty better. (63.01 S/m2)

 RB> Both of which corrode over time in moist air.

Yes, but what is it that you want? Do you want a good conductor, something that
does not corrode or something that has high tensile strength?

Gold only scores well on the corrosive angle. In the end it will always be a
compromise.

 MV>> Gold is used by audio freeks for plating in contacts, But as I
 MV>> have stated elsewhere, Nickel is just as good for all practical
 MV>> purposes.

 RB> Nickel corrodes too. And of course is not as easily worked.

Nickel plating is as easy as gold plating and regarding corrosion it is good
enough for almost all applications. If nickel isn't good enough in regard to
corrosiun, there is platinum. Gold is not irriplaceable.

 RB>>> and diamond is the  hardest-known substance

 MV>> True, but what do you need that for?

 RB> To cut hard materials.

So... how does one cut diamonds?

Diamonds ARE cut you know.

 RB>>>  and is also a good heat conductor.

 MV>> But not unique in that.

 RB> As far as I'm informed, diamond has the highest thermal conductance of
 RB> any material.

I am too lazy too check, but what if it is? Does that make it irreplaceable?
What matters is not if it is the best, but if it is good enough.

 RB> There have been experiments depositing diamond layers on CPUs to
 RB> enhance the heat transfer.

Experiment... IOW, no large scale application.

Other than that, we should be careful not to compare aplles and oranges. Unlike
gold, diamond is not an element. It is a from of carbon and carbon is not
scarse at all. If it ever comes to using diamond in the semiconductor industry,
it will most likely not be the dianonds that are made into gems. It will be
industrial (artificial?) diamond. As you noted elswhere, industrial diamond in
not scarce and therfore not vary valuable. .

I strated out with the statement that gold and diamond are valuable because
people believe they are valuable.

 RB>>>  At present, neither is replaceable for certain uses.

 MV>> Such as?

 RB> See above.

You have not vonvinced me. You mentioned that steenless steel is not as good as
gold for teeth. So what? neither gold nor steenless steel is used any more by
dentists. It is all ceramics. If they need a metal, they use titanium.

Diamond? It is not irreplaceable either. See above.

 RB>>> Gold electrical contacts prevent connection deterioration over
 RB>>> time (platinum is also good, but much more expensive and harder
 RB>>> to work),

 MV>> See above, nickel is just as good.

 RB> Nickel corrodes with time.

very little. And gold is soft, so it wears off faster than nickel. Nickel
corrosion is only a problem in VERY aggressive environments. Environments where
the rest of the electrical circuit than need the contact will not function very
long anyway.

As I mentioned before, irrepleceable does not mean thet it has the highest
property X. It means that for the application at hand something else with a
slightly lower property X is not good enough.

 MV>> Actually I think nickel is better. Gold is soft, it wears off
 MV>> quicker then nickel when the contacts are plugged in and out very
 MV>> often.

 RB> You're concentrating on a single use. My remarks are not limited to a
 RB> single use.

What I am trying to convey is that it does not have to be the same replacement
for every single application. As long as one can find *A* replacement for gold,
for every application it is not ireplaceable. For dental applications, it can
(and is) repleced by ceramics and titanium. If you nee corrosion resistance,
nickel will do for electrical contacts. If you need more, there is platinum. If
you need strength and corrosison resitnace, there is irridium. And so on, and
so on.

 RB>>> and diamond deposited on electronic chips increases the thermal
 RB>>> transfer rate, making for a cooler chip.

 MV>> There are other ways.

 RB> Sure, but not as effective.

Obviously effective enough or my computer would be full of diamonds.

 RB>>> There are also things known as diamond cutters or saw blades for
 RB>>> hard materials.

 MV>> I know. Not irriplaceable either.

 RB> Of course not. You could use your tongue, for example, to cut steel
 RB> ;-)

I ask again: how does one cut diamonds?

 MV>> The fact remains that gold and diamond are very sparsely used in
 MV>> industry and that niether of them are irriplaceable.

 RB> There are no equivalents. Does that suit you better?

That goes for almost anything. That there is no 100% equivalent does not make
it irreplaceable.


Cheers, Michiel

--- GoldED+/W32-MINGW 1.1.5-b20070503
 * Origin: http://www.vlist.org (2:280/5555)