best metal for heatsinks?

[sardonx]

I searched but couldn't find anything. Which metal has the best heat conductivity and heat dissapation? I need to build a heatsink. Anyone know?

[damonpip]

Diamond, silver, copper. I cannot find the link that proves this at the minute though.

[OliverD]

After copper, the list continues with aluminium.

Cheap, easy to work with, non-magnetic, ... There is a reason why everybody keeps using it

[Magura]

Originally posted by damonpip
Diamond, silver, copper.

A truth with modifications.

For heat conductivity, this is correct.

For dissipation, it is not correct.

An anodized black aluminium surface will have far better dissipation properties than any of the above, for the simple reason that you can dye it black. Any of the other materials you would have to paint black.

Magura

[sardonx]

that was a quick response.. thank you.

Aluminum is not a problem to get

[Bill Fitzpatrick]

Copper has better conductivity but poorer dissapation than alum.

[sardonx]

so ideally the chips should be mounted to a copper bar (of appropriate dimensions) and the fins made out of black anodized aluminum...?

[breguetphile]

It needs to be said that just because one material is greater than another does not mean it is appropriate for the job. The reason aluminum heatsinks are used so frequently is because they are best 99% of the time. While you did ask for best dissipation and heat conductivity, I'd keep in mind cost and ease of use.

[Sch3mat1c]

Saphire is also pretty conductive. And it just so happens that's what anodizing produces on the aluminum surface.

I think aluminum is more conductive than copper by density; certainly by cost.

Tim

[Bill Fitzpatrick]

Originally posted by sardonx
so ideally the chips should be mounted to a copper bar (of appropriate dimensions) and the fins made out of black anodized aluminum...?

I'm pretty sure I've seen that done before. Don't forget the thermal resistance between the copper-alum. interface needs to be minimized.