Liquid metal TIM turns solid over time rather than drying out

Roman Hartung tested a gallium-indium-tin alloy across two years using an electron microscope. He says the compound does not evaporate or dry out. It reacts chemically with the metal it touches and turns solid. On bare copper, the reaction creates a layer growing at about 1 µm daily up to 100 µm. This layer conducts less heat than pure copper and becomes impossible to wipe away quickly. Nickel-plated surfaces restrict the reaction layer to a fraction of that thickness. Aluminum destroys itself entirely when exposed. Thermal Grizzly states gallium prices climbed from about €300 per kilogram to €3,000 over five years, while China controls roughly 99% of the supply.