[trissylegs]

No for PC heatsink, but in 3d printing heat is really important for the nozzel. And a company makes them with Polycrystaline Diamond, which is harder than normal diamond. The company needed it themselves as the carbon fibre filament they were using kept wearing out heads. They though "Why don't we make our own heads".

https://www.youtube.com/watch?v=96eFnTescoY

[Animats]

That makes sense. Dies for drawing fine wire have been made of diamond for most of a century. Seems like that's filtered down to 3D printers, which is a less demanding application.