How popular are liquid metals in heat dissipation applications? Let's look at the truth from the perspective of thermal conductivity.

Over the past decade, liquid metal (LM) has surged from heat exchange layers in aerospace fuel pipes to cooling modules in laptops and mobile phones, with "sky-high thermal conductivity" almost becoming its defining characteristic. A 2025 report by market research firm Yole indicates that the global compound annual growth rate (CAGR) of LM thermal materials will reach 321 million tons, surpassing the growth rate of graphite sheets and high-end thermal pastes. Why can a room-temperature flowing metal revolutionize traditional cooling solutions? The answer lies in the microscopic mechanism of efficient thermal vibration transfer through metal-bonded electron clouds, and the fact that Ga–In–Sn alloys can maintain a thermal conductivity of 25–40 W/m·K at room temperature. This article will use thermal conductivity theory as its main focus, combined with measured data and packaging examples, to dissect the scientific truth and engineering challenges behind the explosive popularity of liquid metal.

Thermal conduction mechanism and typical formulation of liquid metal

Commercially available heat dissipation grade liquid metal is mostly based onGallium (Ga)Using an indium (In), tin (Sn), or zinc (Zn) base, the freezing point is lowered (to about −19 °C), forming what is called Galinstan.

• Electron thermal conduction: Although liquid metals lack lattice order, the metallic bonds provide a free sea of electrons, which can also efficiently carry thermal vibrations.
• Convection boost: In gaps with a thickness > 30 µm, liquid metal will generate microscale convection, further improving the equivalent thermal conductivity.

The resistance lies in the high surface tension (≈ 0.7 N/m) and oxide scale, which easily form a "bead effect". Adding 0.1–0.5 wt % copper powder or using plasma activation can reduce the contact angle to < 5° and enhance the interface adhesion.

Thermal conductivity ranking: Liquid metal vs. traditional media

(Values were measured at 25 °C under normal pressure and are arranged in descending order of thermal conductivity.)

Perfect fit with CPU/GPU packages: Why is thermal resistance reduced so significantly?

Wettability: After surface activation, Galinstan can penetrate into the micropores of the copper cover plate (Ra ≈ 0.2 µm) to form an interface transition layer of < 1 µm.

1. Low viscosity: 1.9 mPa·s makes it compatible with both vacuum filling and dispensing processes.
2. No volatiles: Compared to thermal paste, it has less cracking and pumping out, and its lifespan and reliability are increased by 2 times.

Intel's 2024 Meteor Lake Mobile series is the first to use Ga-In LM in a thin thermal module, which reduces the peak CPU temperature by 8–10 °C and shortens the turbine hold time, providing 15% more performance headroom than comparable ceramic filler pastes.

Challenges of conductivity, corrosion and sealing

• Electrical short circuitRisk: Ga-In LM has high conductivity, and any leakage into the PCB or package bump area may cause a short circuit. The solution is to use a PI or Parylene edge spill prevention coating to ensure no leakage after 500 hours of high-temperature cycling.
• Aluminum corrosion: Gallium exhibits a strong segregation tendency towards aluminum, and can corrode and pit at temperatures up to 60 °C. If the heat sink uses Al6063, a Ni-P plating or anodic hardening layer must be applied.
• Oxide layer: Ga₂O₃ film thickness is about 1–3 nm, which inhibits wetting; the film can be continuously broken through 0.05 wt % acidified copper powder or a small amount of fluorinated surfactant.

The trend of solid-state coating and heat dissipation of 3D ICs

1. Solid microcapsules (LM): Ga–In is encapsulated in SiO₂ or polyurea shells. At room temperature, they are flexible gaskets. When compressed, they break open and flow out, then solidify and seal, balancing safety and assembly yield.
2. 3D IC direct contact with internal layers: The research team filled gallium between TSV arrays and used its self-spreading fluidity to create a "self-filling" heat dissipation channel, which can reduce the thermal resistance of stacked HBM to 0.015 K·cm²/W.
3. Dual thermal and electrical properties: Doping Ga-In alloys with bismuth (Bi) or rhenium (Re) can improve electrical conductivity and form reshapeable solder, combining thermal conductivity with reworkable and repairable properties.

The rapid rise of liquid metals (LMs) in the heat dissipation field is largely due to their extremely high electronic thermal conductivity and excellent wetting adhesion, enabling them to create unprecedentedly low thermal resistance within interface gaps of tens of micrometers. However, the risks of conductivity, corrosion, and sealing also make LMs a material with "high technical barriers." If you are looking for a new TIM (thermal insulated interface material) to break through bottlenecks for high-power CPUs, GaN power ICs, or 3D stacked chips, mastering the three key points of interface pretreatment, leak-proof packaging, and material compatibility will allow you to maximize the thermal conductivity advantages of liquid metals while avoiding short circuits and corrosion traps. Liquid metals may not be suitable for all scenarios, but they have already demonstrated decisive advantages in high heat flux density applications; the next step may be to elevate the heat dissipation mindset from "passive heat dissipation" to a new era of multifunctionality that combines phase change regulation and electromagnetic integration.

Want to learn about thermal interface materials, improving heat dissipation performance, and heat transfer?
Further Reading :The Key to Improving Chip Heat Dissipation Performance – Thermal Interface Materials