Do you know about liquid metal?
Reports suggest that liquid metal possesses properties such as fatigue resistance, high strength, hardness, elasticity, and corrosion resistance, making it suitable for applications in phone casings, folding screen hinges, car door latches, golf clubs, cast splints, bearings, and more.
The first time I encountered this information, I was quite puzzled. How can something “liquid” have such “high strength”? How could a liquid be used as a phone casing—wouldn’t it collapse at the touch of a finger? Is liquid metal as “strong as steel” or “soft as silk”? Although there’s plenty of public information online, opinions vary widely. After some research, I realized that liquid metal might not be “liquid” in the way one might think.
Liquid metal actually refers to an amorphous metal, which can be seen as a mixture of positively charged ions and free electron gases. It’s an amorphous, flowable metallic material that includes various low-melting-point metals and alloys that remain in a liquid state at room temperature or slightly heated temperatures. Liquid metal also exhibits high conductivity, hardness, corrosion resistance, thermal conductivity, and wear resistance.
1. Low-Melting-Point Metals, the “Soft as Silk” Liquid Metal
Liquid metal refers to metals that remain liquid at or around room temperature and are also known as low-melting-point metals. In the sci-fi film Terminator, the all-powerful robot was made of liquid metal.
Low-melting-point metals are fascinating materials. Out of the 118 elements on the periodic table, only 22 are nonmetals, while 96 are metals. Yet, only a few metals, like gallium (Ga, melting point 29.76°C), rubidium (Rb, melting point 38.89°C), cesium (Cs, melting point 28.44°C), mercury (Hg, melting point -38.86°C), and francium (Fr, melting point 27°C), are liquid at room temperature, while the rest have melting points in the hundreds of degrees Celsius or higher. Some alloys, such as sodium-potassium alloy, are also liquid at room temperature.
Mercury is the most commonly encountered liquid metal in daily life, found in thermometers, blood pressure meters, and electrodes. However, mercury is highly toxic and volatile, with the potential to cause permanent damage to the nervous, immune, and cardiovascular systems, and in severe cases, death. Other liquid metals, including sodium-potassium alloy, rubidium, cesium, and francium, are too reactive to handle safely in everyday situations. Gallium (Ga), on the other hand, is a relatively safe liquid metal with unique properties. Its melting point is just 29.76°C, so it’s solid at room temperature but melts in the palm of your hand. Gallium’s exceptional thermal conductivity makes it a viable alternative for applications in high-performance computers, power semiconductors, and other heat management systems.
Moreover, as both a “metal” and “liquid,” gallium can flow directionally under electric, magnetic, gravitational, or thermal fields, offering promising applications in 3D printing and integrated circuit manufacturing. While liquid robots like those seen in Terminator remain a distant prospect, research on low-melting-point metals continues to advance, with potential applications still in the theoretical, speculative, or even imaginative stages, far from real-world use.
2. A Rising Star in Metallic Materials
Liquid metal is among the few high-profit materials in the metal industry and could gradually replace existing materials to create breakthrough products. It is widely applicable in consumer electronics, lithium batteries, 3D printing, flexible smart machines, and vascular robotics.
Liquid metal has a strength more than 10 times that of magnesium-aluminum alloys and more than twice that of stainless steel and titanium alloys. Its hardness is similarly more than 10 times that of magnesium-aluminum alloys and 1.5 times that of stainless steel and titanium alloys. With a moderate density, lighter than stainless steel but slightly heavier than titanium, these characteristics make liquid metal a promising third-generation material for 3C products, following engineering plastics and lightweight alloys. With new technological and industrial revolutions on the horizon, liquid metal as a next-gen supermaterial could foster a trillion-dollar market.
Currently, there are three main technical directions in liquid metal technology: ribbon form (already relatively mature), bulk amorphous form, and powder form. Powdered liquid metal has two uses: as a surface coating for wear resistance and corrosion protection, and in 3D printing. Compared to powder metallurgy, which has a shrinkage rate of about 22-24%, liquid metal shrinkage is much lower, around 0.25-0.35%, providing high repeatability and precision.
3. Broad Applications of Liquid Metal
Examples of liquid metal applications include bearings, hinges, SIM card trays, clamps, golf club heads, and watch components. Due to limited suppliers, large-scale application is not yet widespread. Beyond consumer electronics, liquid metal could see applications in military, industrial, robotic, medical, environmental, and aerospace fields, offering significant prospects.
High-end watch brands such as Swatch and Omega have used liquid metal in their products since 2009. The numbers and markers on watch dials are crafted from liquid metal, which adheres seamlessly to ceramic bezels, with zero gaps. Zirconium (Zr), a key element in liquid metal alloys, is also a significant component of zirconium dioxide (ZrO2) ceramic material. The two materials’ excellent hardness ensures a perfectly smooth, wear- and corrosion-resistant bezel.
In the consumer electronics industry, Apple introduced liquid metal for SIM ejector pins, taking advantage of its superior hardness, corrosion resistance, and wear resistance. Other brands like OPPO, Vivo, and Huawei now use liquid metal SIM trays and hinges. With advances in bulk forming technology, liquid metal could soon be widely applied in smart devices’ structural components, heralding a new “liquid metal era.”
4. Significant Industrial Potential of Liquid Metal
Liquid metal, still in its early industrial phase, has major commercialization potential. As a high-tech material, liquid metal’s outstanding physical, chemical, and mechanical properties make it a crucial material in advanced sectors like electricity, electronics, computing, and communications. The demand is immense, and its development and application could spur progress across multiple related fields.
In electronics, liquid metal’s high efficiency, low loss, and high magnetic conductivity can support the development of electronic components towards higher frequencies, efficiency, energy savings, and miniaturization, potentially replacing traditional materials like silicon steel, permalloy, and ferrite. With its commercial production beginning in 2018, demand for bulk amorphous liquid metal continues to grow in sectors such as electric vehicles, 5G communications, and consumer electronics. Products like liquid metal Face ID brackets have been supplied in bulk to companies including Xiaomi, OPPO, and Huawei; 5G base station products such as filters and heat dissipation shells are also in production, with partnerships established with companies like Tesla, Samsung, Lens Technology, and ABB.
As a foundational and strategic industry, new materials like liquid metal are crucial for high-tech advancement, with governments worldwide implementing policies to support its development. Liquid metal’s potential applications could not only drive industry upgrades but also create a market space valued in the trillions.