How fast do you want your heat to flow ?
Well, how much money do you have ?
Some thermal conductivity numbers:
Al - 237
Cu - 401
Ag - 429
CUSIL - 515
Let me see, if a 6.5% increase (Cu/Ag) is worth a 5X increase in material cost, then a 22% (Cu/CUSIL) increase would justify a 15X cost increase, unfortunately the increase in cost is not linear - but exponential.
CUSIL (WESGO Metals) is the eutectic alloy (lowest melting temp) of Ag and Cu ? 72%Ag & 28%Cu
This material is sold as Cusil in the US (or Eutectic Alloy H12 in the UK) for brazing; only in fine wire or thin sheet form.
Wesgo has a continuos casting process which at one point has the metal at 1/4 in. thick and 5.5 in. wide. They were gracious enough to quote me a price for a 2 x 5.5 x 1/4 in. piece: $517.96, plus shipping.
(Quote based on spot Ag $5.36)
Cut into 3 cold plates, about $180 each.
So I went to a casting co for a "custom" alloy, $200 each, IF the 1st pour was a success.
If anyone can come up with a reasonably priced source, please post it.
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