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Metal foams are used in many applications, including cooling and filtration. Start-​up Apheros’ novel metal foams offer unprecedented properties.

Dr. Julia Carpenter from the Complex Materials Group at ETH Zurich is the co-​inventor and driving force behind the young company. Her metal foams have a unique microstructure. Compared to existing products, they impress with very low weight, an extremely large surface area and the ability to absorb liquids. These properties are achieved through a newly developed production method and enable the use of these metal foams in various applications.

Cooling of electronic devices

By 2030, electronic devices will consume 23% of global energy. Almost half of this, 10% of global energy, will be used for cooling. Currently, so-​called “heat sinks” are used. They are usually supported by energy-​intensive fans and air conditioners. High-​end applications also use liquid cooling systems with heat exchangers. Metal foams enable efficient cooling without consuming energy. They are ideal passive heat exchangers and do not require fans or air conditioning.

Easy manufacture

For her metal foams, Julia Carpenter uses steel, nickel, and copper particles, which are reshaped by a special foaming and sintering process. Compared to existing products, Apheros’ metal foams have a surface area that is 100 to 1000-​fold larger.

The open-​porous structure and the large surface area enable effective passive cooling because heat is exchanged on the surface. The larger the surface, the more heat is released.

The metal foams are ultra-​porous, which brings another advantage: they are very light - not even half the weight of aluminium - and float on water when given a water-​repellent coating. In their basic state, the foams absorb liquids - even high-​viscosity liquids such as glycerol. The basic properties of metal, such as thermal and electrical conductivity and mechanical stability, are retained. These foams are suitable for applications where fans should not be used, or which are cooled with liquid (heat exchangers).

Applications in filtration, catalysis, and electrodes for batteries

Apheros’ metal foams are not only suitable for cooling applications, but also for filtration and catalysis. When filtering oil, for example, the metal foams allow the absorbed oil to be burnt out, so that the filter can be used again.

In catalysis, the metal foams act as both a direct catalyst and a catalyst substrate. For example, the foams could be used in the Haber-​Bosch process for nitrogen fixation, or for electrolysis to produce hydrogen. The advantages of the metal foams in catalysis lie in their solidity - they are much easier to handle and clean than the granular variant currently in use.

According to Julia Carpenter, another application with potential is in the field of electrodes for batteries. Here she is collaborating on research projects with ETH and Empa to further develop the technology. At the same time, her team is working on producing prototypes for liquid cooling.

Looking for partnerships

It all started with Julia Carpenter’s doctoral thesis, for which she developed the novel metal foams. Because the product was almost ready for the market, she decided to commercialise her invention. “The technology is mature, the material works and can be easily adapted depending on the use case,” says Julia. The metal foams are patent pending. Julia is now looking for partners who have clear ideas for a “proof of concept” collaboration. Whether this is in the field of cooling, filtration, catalysis, or electrodes makes no difference - she is open to everything.”

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