what metal is better for a heatsink pper or aluminum?
It's true Cu retains heat better than AlHere are the simple clues: Cu have higher conductivity and Specific heat than AlConduction (CPU/Transistor to heatsink) needs good thermal conductivityConvection (Heat sink's fins to ambient air) needs a lot of surface area simple explaination: While with higher conductivity, Cu will transport heat faster, but with the higher specheat Cu will stores more energy than Al (at the same shape and volume) while having the same surface area, thus Cu will be harder to dissipate convectively Now the long explaination: Copper is a good candidate as first line 'heat sink', it will absorb a lot of energy before increasing 1 deg, meaning for a CPU at 47 deg and ambient at 27 deg, it will hold 27282930 deg longer than Al as it heats up- GOOD now comes the drawback, with the high specific heat, when copper try to release heat to ambient air, it will maintain it's hot temperature longer than Aluminum simply because it has to dissipate more energy to ambient air before dropping 1 deg in tempSo, let's imagine copper fins with the same shape and volume as Al, it will take a lot more air to cool the copper (not to mention it's heavier too) than the Al- BAD Thus the reason using Al for fins, and copper for heat block (sink)asborbing heat from transistor or CPU got to do with small contact surface area, in which case higher thermal conductivity allows lower interface junction temp)while the Al fins dissipate heat more efficiently (in terms of heat flux/weight/size) than cooper.
