Liquid Metal Thermal Paste Reacts With Copper
Microscope testing reveals that liquid metal thermal interface materials bond with bare copper to form a solid compound.
Updated on Oct. 16, 2026 in Materials Science
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A two-year electron microscope study has confirmed that liquid metal thermal interface material reacts with bare copper to form a solid compound called CuGa2. This reaction creates a layer that grows by approximately 1 micrometer per day, significantly impacting thermal conductivity.
Why it matters
Understanding this chemical reaction is vital for maintaining hardware cooling efficiency, as the resulting solid layer performs worse than pure copper. The issue highlights broader supply chain vulnerabilities related to gallium, a metal critical for cooling applications.
The gallium-indium-tin alloy melts at 11 degrees Celsius, but its reaction with copper creates CuGa2, which has a thermal conductivity of 100 W/mK compared to copper’s 400 W/mK. Nickel plating can limit this solid layer to be 10 times thinner than on bare copper.
The players
Thermal Grizzly
This company specializes in high-performance thermal interface materials and cooling solutions for computer hardware.
The details
When liquid metal touches bare copper, the gallium bonds with the metal to create the CuGa2 compound, which eventually reaches a maximum thickness of 50 to 100 micrometers. While nickel plating can mitigate this by forming NiGa5, researchers continue to analyze the physical degradation of cooling interfaces over time.
Timeline
2018: A Skylake-X CPU was delidded and utilized with liquid metal.
September 30: Thermal Grizzly released a blog post regarding metal polish.
October 16, 2026: The research results were published.
November 27, 2026: China is scheduled to end its current suspension of gallium export bans.
The Big Picture
This research follows the documented trend of China's 99% global market share of gallium supply, which currently dictates industry pricing and availability. The finding that liquid metal interacts poorly with copper forces a paradigm shift in how high-end cooling solutions are engineered.
Users applying liquid metal to bare copper surfaces should be aware that the interface will degrade as a solid compound forms, potentially leading to higher CPU temperatures over time. Upgrading to nickel-plated hardware or alternative pads can help maintain cooling performance and extend the lifespan of heat-sensitive components.
The takeaway
Computer users should avoid applying liquid metal directly to bare copper surfaces to prevent the formation of insulating solid layers. Engineers are increasingly looking toward nickel plating and graphene-based alternatives to ensure cooling stability amid rising gallium costs.
What happens next
Thermal Grizzly plans to replace current nickel coatings with new materials next year and intends to release a new version of its KryoSheet graphene pad shortly. Additionally, the market will monitor the status of China's gallium export restrictions, which are slated to end on November 27, 2026.
Further reading
Learn more about the latest innovations in Materials Science.
Source note: This article includes information reported by Tom's Hardware.
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