Cusil not verry good

[webmedic]

Save your money on this guys. I called wesgo metals and talked to thier lead r&d guy. He told me that the figures on thier site that showed the thermal conductivity to be verry high were taken about 30 years ago with instriments that were verry inacurate. He retested it for me and emailed the new results. He also fixed the inacurate results on the site.

The link to his site:
http://www.wesgometals.com/physdata.html

The email he sent me:
As I mentioned on phone, the thermal conductivity of Cusil is 371 ohm/m/K.

Should you have any question, please contact me.

Toshi Oyama, Ph.D.
R&D Manager
WESGO Metals
610 Quarry Rd.
San Carlos CA 94070

[Hoot]

Just looked at the revised chart. Wow, what a difference. If those figures are correct, there are a lot of vendors holding the bag on Cusil cold plates and other cooling products using Cusil. Hard to believe that any mix of Silver and Copper, regardless of percentages, is less conductive than Copper alone. I think I'd get a second opinion on that one.

73, Hoot

[webmedic]

I can give you the guys phone nuber if you like. It's also harder than copper by a small amount so it is harder to mill. Yes i would shure hate to be any of those companies that didn't check thier data first.

[Sonny]

What are the percentages of Silver & Copper on their CuSil alloy? We do need a second oppinion on this:confused:

Talking with Tetsuji Kataoka from ALPHA NOVATECH that the only reason that they do not use CuSil is because of cost but their tests show a substantial gain over Copper & Silver. Now I'm confused:mad:

[BillA]

oooohhh . . . .

I've been pursuing the same info from a different source, Handy & Harman
who also sell this alloy as a brazing matl

they use the (widely accepted) "Wiedemann-Franz" relationship to predict the thermal conductivity of silver alloys based on their measured electrical conductivity

they too suspected that the Wesgo data was old and inaccurate

yet again, no silver bullet

be cool

(I should probably put an addendum on the Cold Plate article)

[BillA]

webmedic

the units given you by Wesgo are not correct
(the ohm part is for electrical resistivity)

did they actually MEASURE the thermal conductivity ?
or, like Handy & Harmon, calculate it ?

(as "ohms" are mixed in, I'm suspecting it's a calculated value)

if you think it's better to have only one person quizzing him, give him another call

or you can PM me with his phone # and I'll call him, and post the results

there is another individual who promised actual lab test values, I'm in pursuit of that info also

be cool

[webmedic]

BillA I just pm'd his email and phone number to you. Yes He did say this was based on electical conductivity. He also stated that the differences could vary by as much as 10% for thermal conductivity. Even if this is the case a 10% diff on the good side whould only be aroud 410 max. Not near as high as thought. Not even ashigh as silver by itself. Which would seem correct. This figure places it dirrectly between silver and copper which it should be.

[Aesik]

Hrrmmm.....well, assuming the newer data is more correct and that the conductivity isn't near what the older numbers lead us to believe, I'll certainly not be wasting my cash on any Cusil for my experiments ;) Thanks for the heads up and please keep us updated.

[BillA]

confirmation today from WESGO

webmedic's description accurate

still waiting on some actual lab test data

be cool

[Slain]

I have been looking in Cusil and can't find to seem any hard data, Can't wait to see if ihis is correct

Alloying metals can change there properties dramatically i.e.

Beryilium thermal conductivity is 216 w/m-K
Copper " " " 365 W/m-K


Beryilium copper alloy 98.3% Cu 1.7% Be is 118 W/m-K much lower than before.

[UserName]

All alloys of anything i know of will reduce thermal conductivity to less than the lowest element by it self, in general.