Oxide scales develop on the outer surface of alloys at high temperatures creating a protective barrier that keeps destructive carbon-bearing molecules from slipping into the alloy. The diffusion of carbon into oxide scales should be negligible, but studies have shown that carbon can sneak through the oxide line of defense leading to brittleness and corrosion.
"The United States loses four percent of the gross national product due to alloy corrosion," Argonne Distinguished Fellow Ken Natesan said. "A network of continuous metal nanoparticles allow the carbon to dissolve and diffuse through the protective oxide scales without the need of a crack or a pore."
It was commonly believed that carbon-containing molecules escaped into cracks or pores in the oxide scales, but using three separate techniques -- nanobeam x-ray analysis at the Advanced Photon Source, magnetic force microscopy at the Center for Nanoscale Materials and scanning electron microscopy at the Electron Microscopy Center -- Natesan, along with Argonne scientists Zuotao Zeng, Seth Darling and Zhonghou Cai, discovered networks of iron and nickel nanoparticles embedded within the oxide scales.
Carbon can easily diffuse through the metals and create a path for carbon atom transport which does not involve defects in the scale.
"By examining the oxide scale, we find the metal nanoparticles," Zeng said. "If they are eliminated we can create a more corrosion-resistant and longer lasting alloy."
Based on the study, ANL has developed laboratory size batches of materials that exhibit as much as ten times longer life than commercial alloys with similar chromium contents, Natesan said. At present, 50-lb batches of the alloys have been cast successfully by an alloy manufacturer and will be commercialized in due course. The ANL-developed alloys are of considerable interest to the chemical, petrochemical, and refining industry.
The findings might also have broad influence on not only metal dusting and carburization, but also in other research areas such as alloy development and surface coatings for high-temperature fuel cell applications.
Funding for this research was provided by the U.S. Department of Energy, Office of Industrial Technologies. The Argonne scientific user facilities such as the Advanced Photon Source, Electron Microscopy Center and Center for Nanoscale Materials are supported by the U.S. Department of Energy, Office of Science.
A paper based on this work has been published recently in Nature Materials.
Argonne National Laboratory brings the world's brightest scientists and engineers together to find exciting and creative new solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.
Brock Cooper | Newswise Science News
New design improves performance of flexible wearable electronics
23.06.2017 | North Carolina State University
Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology