Liquid metal TIM doesn't dry out — it turns solid by bonding with copper

der8auer examined a two-year-old liquid metal TIM application under an electron microscope and found it doesn't dry out: gallium reacts with copper to form solid CuGa2 with about 100 W/mK conductivity versus copper's 400. The layer grows roughly 1 µm per day up to 50–100 µm, while nickel plating keeps it about 10 times thinner.

• Liquid metal doesn't dry out: gallium forms solid CuGa2 with copper
• CuGa2 conducts heat at about 100 W/mK versus 400 for bare copper
• Layer grows ~1 µm per day up to 50–100 µm, melts only at 254 °C
• Nickel plating caps the layer at 1–5 µm but NiGa5 conducts worse