A researcher at the Universidad del Valle (Univalle) tested an alloy under conditions for uses close to medical ones and also to elucidate possible methodologies to explore similar materials, as part of her master's project.
Corrosion is damage produced by reactions (electrochemical) while wear is more by contact interactions and relative movement (physical). The field of tribocorrosion tries to study the combination of the two phenomena and look for solutions that can decrease the damage they do.
This is important because about 23% of the total energy consumption in the world originates from tribological contacts and if new surfaces, materials and lubrication technologies are developed, the world could save the equivalent of 1.4% of annual GDP and 8.7% of total energy consumption in the long term (15 years), according to an
international study.
Durante las dos últimas décadas, las aleaciones que son una mezcla de Hierro, Manganesa, Aluminio y Carbón (Fe-Mn-Al-C) han sido ampliamente investigadas para aplicaciones industriales debido a su baja densidad y a su excelente combinación de resistencia y ductilidad en comparación con los aceros convencionales de alto manganeso.
In the paper "On the Tribocorrosion Behavior of Fe-Mn-Al-C Alloys in Ringer’s Solution" published in the journal Metals in August 2022, Gisselle Marcela Barona, a physicist; master's researcher and the lead author, found that for one case, depending on the applied potential, the addition of aluminum promoted the formation of precipitates on the surface of the material forming a porous barrier between the alloy and its environment.
Barona said that in the other case, the addition of aluminum promoted the formation of a protective phase in some areas of the material's surface.
"The study was part of a larger project to examine the wear resistance of these alloys," Barona said, adding that Ringer's solution, in which the alloys were immersed, is a saline fluid with a salt and pH balance similar to that of the human body.
The Research
In the scientific publication, Barona and co-workers detailed how they produced 6 mm thick alloy plates and, after cooling, the plates were treated in solution at 900 ◦C for one hour and then cooled to reach the final condition.
They were then subjected to exposure to Ringer's solution and mechanical wear at the same time. Then, they used Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) along with other techniques to observe the effect of tribocorrosion.
Professor Sara Aida Rodríguez, a researcher at the Fatigue and Surfaces Research Group and also Barona's supervisor, said that these alloys are lighter and more economical than current options.
"Conventional materials such as chromium and nickel, which are present in stainless steels, form a passive film on the surface and stabilize the austenite phase, respectively, and in the project, we found similar behavior with aluminum and manganese," Professor Rodriguez explained.
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Image: A Scanning Electron Microscopy (SEM) images, showing the effect of tribocorrosion. Credit: Gisselle Marcela Barona.
Impact of the work
Both Barona and Rodriguez commented that Barona's project is an early step in exploring the possibilities of this material, both in household utensils and medical applications.
"Although they may have medical applications, for example in orthopedics, these alloys are also more affordable than conventional alloys containing chromium and nickel," said Professor Rodriguez.
The researchers said that if Colombia is going to manufacture these alloys, it could be a great competitive advantage for the country.
"With these alloys, we can think about how Colombia can move the local economy forward," said Barona, adding that a local industry could lower the costs associated with imports.
In addition, Professor Rodriguez explained that Barona's project had a great impact on the scientific field.
"Previously, there was no written method for the assays that Marcela did and now all the details are there so that anyone can follow the same method with other alloys," Professor Rodriguez said, adding that it was a great achievement that Barona could do this work during the toughest years of the Covid-19 pandemic.
Barona said she is now looking for opportunities for doctoral research abroad.
"In tribology research, there is a good group at EPFL in Switzerland," Barona said.
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