Four decades of magnets: how literature has addressed their sustainability

Nd-Fe-B rare earth magnets are crucial components in emerging technologies such as wind turbines and electric motors. In a scenario of decarbonization of the global economy and given the need to reduce dependence on fossil fuels, the expansion of wind energy and the adoption of hybrid and electric vehicles should considerably increase the demand for these magnets. However, the extraction and processing of rare earths, as well as the manufacture of Nd-Fe-B magnets, have their own environmental burdens that, when neglected, can compromise the sustainability of the so-called “green” technologies. In the year 2023, Nd-Fe-B magnets reached four decades of existence. Due to its relevance, several studies were developed and published during this period, but none of them present the sustainability perspective review. So, what are the key sustainability challenges in the academic literature on Nd-Fe-B magnets over the years? To answer the research question this paper presents an analysis of the key words from 3,151 papers listed in the Scopus database, between 1984 and 2023. Knowledge mapping, based on VOSviewer, reveals the direction and evolution of academic literature on this subject, based on the identification of the most studied topics and their interrelations. Considering the necessity of a Nd-Fe-B supply chain more sustainable and resilient, topics such as circular economy, recycling and remanufacturing were mapped, identifying gaps and highlighting research opportunities.