Magnetic and microstructural analysis of sintering effects at rare earth magnets (NdFeB) using the "grain boundary diffusion" at 800 °C and 900 °C

• Grant number: 23/06160-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: May 31, 2024
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Physical Metallurgy
• Principal Investigator: Mateus Botani de Souza Dias
• Grantee: Gabriele Yumi Sato Shimizu
• Host Institution: Escola Politécnica (EP). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Aiming to implement more sustainable practices, Brazil has set a target during COP-26 to reduce carbon emissions by up to half. One way to achieve this will be to replace the fleet of internal combustion engine vehicles with hybrid/electric ones and increase energy generation from alternative sources such as wind power. Therefore, it is important to implement more efficient electric motors and wind turbines that use rare-earth-based super magnets, i.e., NdFeB. However, the sale of these magnets is currently under Chinese monopoly, making Brazil subject to commercial fluctuations which could have a direct impact on the national electric motors and wind turbines supply chain. The present project aims to analyze the technical feasibility of recycling NdFeB magnets and the effects of grain boundary diffusion (GBD) treatment on the magnetic properties of the material. For this purpose, the hysteresis cycles of commercial, recycled, and GBD-treated samples at two different temperatures (800 °C and 900 °C) and two different times (1 and 10 hours) will be compared. With the results obtained, it is expected to find the condition whose characteristics correspond to the highest values for the remanent field, coercive field, and BHmax. In addition, chemical, microstructural, and magnetic domain analyses will be performed to explain the changes in magnetic properties. Thus, it is expected that the results obtained by this project will validate the technical feasibility of applying the GBD treatment in the recovery of magnetic properties of rare earth super magnets after recycling.