Its going to be one of these:
1. Copper with Nickle plate.
2. Anodized Alu.
Common practice however is not to mix disimular metals like that especially ones that high on the galvanic table, because if moisture, and yes its a electronic which is moisture phobic, but if by some chance moisture did get in, you would get corrosion on the sink.
So im really leaning to 1 more then 2.
But after reading the thread on what you want, it seems this is a laptop, and i highly do not recommend you using liquid metal on a laptop, unless u really know what your doing.
This not a stationary device, liquid metal is liquid at hotter temps.
A laptop is not always in 1 direction and tends to be tossed around in many different orientations which could cause leakage unless again, you know what your really doing.