Text 30617, 89 rader
Skriven 2009-04-01 16:40:56 av Robert Bashe (2:2448/44)
  Kommentar till text 30506 av Michiel van der Vlist (2:280/5555)
Ärende: Gold
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Michiel van der Vlist wrote to Robert Bashe on Monday March 30 2009 at 21:10:

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".

Nice joke. What doesn't?

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

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

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

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

Both of which corrode over time in moist air.

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

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

RB>> and diamond is the  hardest-known substance

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

To cut hard materials.

RB>>  and is also a good heat conductor.

MV> But not unique in that.

As far as I'm informed, diamond has the highest thermal conductance of any
material. There have been experiments depositing diamond layers on CPUs to
enhance the heat transfer.

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

MV> Such as?

See above.

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

MV> See above, nickel is just as good.

Nickel corrodes with time.

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

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

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

MV> There are other ways.

Sure, but not as effective.

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

MV> I know. Not irriplaceable either.

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

RB>> You're mainly talking about bulk products and hoarding, where both
RB>> gold and diamonds _would_ be replaceable _if_ there was anything
RB>> equally desirable to replace them with. But at present, and for the
RB>> last few thousand years, that hasn't been the case.

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

There are no equivalents. Does that suit you better?

Cheers, Bob

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