Experiment shows liquid metal TIM doesn’t dry out; it turns solid
Der8auer’s two-year electron microscope test shows liquid metal’s gallium turns solid on copper and nickel-plated coolers.
Hardware YouTuber der8auer, CEO of Thermal Grizzly, conducted an experiment to test if a two-year-old liquid metal thermal interface material (TIM) would dry out. The TIM is made of gallium and indium, often with tin, and is liquid at room temperature. When tested under vacuum or nitrogen, the TIM did not dry out, but instead bonded with copper to form a solid compound, CuGa2.
This bonding resulted in a solid layer that was about 10 times thinner than the bare metal, and had a heat conductivity of around 100 W/mK. The TIM continued to form a solid compound over a period of two years, with no further changes observed. The TIM's performance is particularly beneficial for high power density components, such as the RTX 5090 and RTX 5080 GPUs, which have twice and three times the power density of the 8800 GTX.
The TIM is still present even after solidifying, but in a different form. The reaction with nickel-plated coolers resulted in NiGa5, which is also solid at room temperature. Thermal Grizzly plans to replace nickel with new coatings and will release a new version of its KryoSheet graphene pad for bare dies. The cost of gallium has more than doubled since the beginning of 2025, with China supplying 99% of the world's gallium.
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