Researchers at the Max Planck Institute for Sustainable Materials (MPI-SusMat) have developed a promising process that can significantly improve the production of Invar alloys. These alloys are essential for sectors such as aerospace, the energy transition, and the production of precision instruments.
The study, published in the journal Nature, describes a one-step, carbon-free process that substantially reduces energy consumption.
Improved Mechanical Properties, Reduced Energy Consumption
Metal production accounts for about 10% of global CO₂ emissions worldwide. For example, iron production releases two tons of CO₂ per ton of metal produced, while nickel production can emit up to 14 tons of CO₂ per ton, depending on the ore type.
The new MPI-SusMat process integrates extraction, alloy formation, and thermomechanical processing into a single reactor and process step, using hydrogen instead of carbon as the reducing agent.
Professor Dierk Raabe, Managing Director at MPI-SusMat and corresponding author of the study, explains the advantages of the new method:
"Firstly, the hydrogen-based reduction produces only water as a byproduct, so no CO₂ emissions occur. Secondly, pure metals are obtained directly, meaning the carbon does not need to be removed from the final product, saving time and energy. Thirdly, we conduct the process at relatively low temperatures, in the solid state. Fourthly, we avoid the frequent cooling and reheating that are required in conventional metallurgical processes."
The Invar alloys produced using this process are not only more environmentally friendly but also exhibit improved mechanical properties, such as increased strength through finer grain sizes – a direct advantage of this method.
Potential for Future Applications and Sustainability
However, scaling this process from the laboratory to an industrial level presents challenges. In particular, the use of less pure, industrial oxides and the economic aspects of hydrogen usage remain hurdles to be addressed.
The institute is currently exploring process variations with different hydrogen concentrations to achieve an optimal balance between consumption and cost.
Future applications of the technology could include the production of high-entropy alloys as well as recycling metallurgical waste into new valuable materials, further enhancing sustainability in materials science.
This development could make a significant contribution to reducing carbon emissions in the metal processing industry and potentially lead to a paradigm shift towards more eco-friendly technologies in alloy-dependent heavy industries.
