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Trial lecture
May 07, 10:15 Auditorium 2, Chemistry Building
Trial lecture title: “Recycling of Nd-Fe-B Permanent Magnets”
Conferral summary / Kreeringssammendrag
Denne forskningen utforsket metoder for å fremstille tetrataenitt kunstig, en bærekraftig jern-nikkel-legering som kan erstatte dyre magneter av sjeldne jordmetaller i grønn teknologi. Ved å kontrollere de strukturelle defektene som oppstår under fremstillingen, undersøkte dette arbeidet viktige kinetiske barrierer og la et avgjørende grunnlag for fremtidig produksjon av disse strategiske og potensielt høytytende magnetene.
Main research findings
This research provides critical insights into synthesizing tetrataenite, a meteorite-derived iron-nickel alloy that could replace expensive rare-earth permanent magnets in green technologies.
And to artificially produce this material, I used mechanical activation techniques, such as cryomilling and cold rolling, and added elements such as carbon, molybdenum, and aluminium. These methods aimed to increase atomic mobility and speed up the slow atomic ordering process. We followed this with long-term heat treatment (annealing) at a temperature just below the alloy’s order-disorder transition temperature (estimated to be around 320 °C).
But, perfectly recreating the highly ordered atomic structure of tetrataenite in bulk form proved exceptionally challenging, and it could not be definitively confirmed in the studied samples.
Therefore, I focused on understanding the precise microscopic changes that occur during these manufacturing attempts. I successfully identified the formation of specific structural imperfections, known as planar defects (such as stacking faults and twinning), in the processed materials. By evaluating how these microscopic defects and chemical additions influence the iron-nickel structure, my findings decode key kinetic barriers, laying essential groundwork for producing sustainable, high-performance permanent magnets.
Candidate contact information
E: mail: valmir.silva@ife.no
Telephone: +47 922 57 207
Adjudication committee
Scientific Group Leader Dr. Thomas George Woodcock
Leibniz Institute for Solid State and Materials Research, Dresden, Germany
Senior Professional Research Associate Petra Jenuš Belec
Jožef Stefan Institute, Ljubljana, Slovenia
Postdoctoral Researcher Ken Luca Abel
Centre for Materials Science and Nanotechnology, University of Oslo, Norway
Chair of defence
Professor Unni Olsbye, Department of Chemistry, University of Oslo
Supervisors
Head of Research Bjørn C. Hauback, Department of Chemistry, University of Oslo
Senior Scientist Stefano Deledda, Ife, Norway
Professor Emeritus Helmer Fjellvåg, Department of Chemistry, University of Oslo
Scientist Christoph Frommen, Ife, Norway