Funding from the US Division of Vitality’s Fermi Nationwide Accelerator Laboratory has enabled researchers at Northwestern College and Fermilab to invent a brand new course of for 3D printing high-temperature superconductors. This technique is the primary to manufacture 3D printed ceramic superconductors with a monocrystalline microstructure and is at present awaiting US patent approval. Their paper was printed in Nature Communications.
Superconductors are a particular sort of fabric that may conduct electrical energy with zero resistance, however solely at extraordinarily chilly temperatures. Excessive-temperature superconductors are distinctive as a result of they work at temperatures larger than conventional superconductors, making them extra sensible for functions.
Cristian Boffo, a co-author on the paper, secured funding for the challenge via Fermilab’s Laboratory Directed Analysis and Growth program. Boffo is the challenge director for the Proton Enchancment Plan-II, a challenge constructing a state-of-the-art superconducting linear accelerator at Fermilab.
Boffo acquired LDRD funding to develop superior magnets known as superconducting undulators, aligning with actions deliberate in Fermilab’s Utilized Physics and Superconducting Expertise Directorate. One of many challenge’s goals is to discover new applied sciences that may revolutionize the design and manufacturing of superconducting undulators via the introduction of high-temperature superconductors and 3D printing.
“Fermilab desires to make higher and higher magnet programs which can be extra environment friendly and attain increased efficiency,” mentioned Boffo. “Northwestern gives the expertise in 3D printing, and we offer expertise in superconductors.”
Excessive-temperature superconductors
When electrical energy flows via a fabric at regular temperatures, there’ll at all times be some power loss resulting from resistance. Over 100 years in the past, scientists found the phenomenon of superconductivity: when introduced right down to temperatures near absolute zero – minus 460 levels Fahrenheit (minus 273 levels Celsius) – supplies lose electrical resistance, enabling electrical energy to maneuver via them extraordinarily effectively. This requires costly and hard-to-handle coolants like liquid helium.
Within the Eighties, scientists found high-temperature superconductors that might function at a better – albeit nonetheless frigid – important temperature of minus 321 levels Fahrenheit (minus 196 levels Celsius). These are largely ceramic supplies, typically copper oxides mixed with different metallic oxides. These superconductors could be cooled with liquid nitrogen as an alternative of liquid helium.
“Utilizing liquid nitrogen, it’s a lot inexpensive to chill down the construction to the place it turns into superconducting,” mentioned David Dunand, a professor of supplies science and engineering at Northwestern College who carried out the analysis.
At present, technological makes use of for superconductivity vary from low-loss energy mills to electrical motors, from medical imaging know-how to fast, quiet magnetically levitated trains. However superconductors’ want for excessive chilly limits their usefulness, so growing high-temperature superconductors is important for advancing on a regular basis functions. And in physics, high-temperature superconductors are particularly advantageous as a result of they maintain their superconductivity in increased magnetic fields than conventional superconducting supplies do.
Polycrystals to monocrystal
To 3D print superconducting ceramics, scientists begin with a ‘precursor powder’: a finely milled mixture of chemical compounds. They mix the powder with a binder to create a printable paste, which might then be extruded by a 3D printer to construct a construction, layer by layer – just like the coil approach of constructing pottery. The construction is then heated and baked in a furnace, a high-temperature course of often known as sintering.
The ensuing piece has a polycrystalline microstructure, however this isn’t excellent for creating or trapping a powerful magnetic area. A monocrystalline superconductor would have a lot better properties for potential makes use of in accelerator physics, but it surely can’t be made by way of powder 3D printing.
So Dunand and his graduate pupil Dingchang Zhang sought to show, for the primary time, a solution to mix the superior physics properties of a monocrystalline superconductor with the complicated structure of a 3D printed polycrystalline construction.
The brand new paper outlines their profitable technique. They 3D print a ceramic polycrystalline superconductor utilizing widespread precursor powder combination known as yttrium barium copper oxide, or YBCO. As soon as it’s sintered, researchers place a single-crystal seed made from a distinct superconducting materials, neodymium barium copper oxide, or NdBCO, on high. They then start a course of known as high seeded soften progress: heating the printed construction so it partially melts, filling holes or pores within the 3D printed microstructure, making it extra sturdy. Researchers then cool the construction very slowly so it re-solidifies with the identical crystallographic orientation because the seed. The ultimate piece retains its authentic 3D printed form, now with a stronger monocrystalline construction.
Dunand and Zhang used their technique first with a 3D printed micro-lattice form, then graduated to extra complicated shapes. They discovered they might use a single seed to manufacture superconducting items as much as 10 centimeters in diameter. They even used their technique to 3D print a foil of superconducting materials that Zhang folded into the form of a tiny paper airplane, demonstrating that 3D printed superconductors could be shaped into complicated shapes with sharp corners.
Sooner or later, they hope to analyze multi-seed strategies – completely different from the polycrystal technique – wherein they hope to provide bigger items through the use of many separate single-crystal seeds.
“If we wish to use it for accelerators, we have to print bigger components,” mentioned Zhang, who accomplished his PhD at Northwestern in August 2024. “If we wish to get greater components, how will we place the seeds? Whether or not that can produce other issues, we don’t know.”
Dunand mentioned their technique “made an enormous step ahead” by exhibiting it’s attainable to create monocrystal superconductors with complicated shapes. They hope it additionally conjures up additional analysis into 3D printing monocrystal ceramics.
“I believe it’s extremely, extremely scalable,” mentioned Dunand. If they might do it of their lab at Northwestern, Dunand mentioned he thinks it may be replicated in lots of different settings.
“This new know-how will allow new magnet designs, resulting in increased performances and doubtlessly even permit the manufacturing of a brand new era of superconducting radio-frequency cavities,” mentioned Boffo. “I believe that this was a really profitable collaboration.”
Fermi Nationwide Accelerator Laboratory is America’s premier nationwide laboratory for particle physics and accelerator analysis. Fermi Ahead Discovery Group manages Fermilab for the US Division of Vitality Workplace of Science.