post #21 of 21
The best material for the bottom of a cpu waterblock would be... No material at all. Means direct contact of water with the CPU top interface. Good sealing, water turbulence and speed can be achieved with not so much problem. I wonder why no manufacturer offers such a solution.

But, now, we can use a near perfect metal TIM with Indium based "indigo Xtrem". So, the best choice for bottom of a cpu waterblock would be a very good conductive metal, like coper. Less expensive than silver with quite the same th. conductivity.
The only problem of coper is it can be oxidized with means a degraded thermal conductivity. Solution is very simple and already used: a thin plating with Nickel, witch is the better non oxidative metal with a decent thermal conductivity (the micron thin layer of nickel will not degrade conductivity performance of the coper). Same process for the inside (contact with water) and outside (contact with air) part of this item.
Nickel is the metal used on the surface of Intel processors, by the way, for this same reason.