Influence of Different Temperatures on Hydrogen Decrepitation of Scrap Hard Disk Drive NdFeB Magnets
Loading...
Date
2026-01-15
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Turkish Energy, Nuclear and Mineral Research Agency (TENMAK)
Abstract
Demand for rare earth elements (REEs) in NdFeB permanent magnets used in wind energy
and EV necessitates efficient recycling to address supply chain vulnerabilities and
environmental concerns. Hydrogen decrepitation (HD), hydrogen-assisted decrepitation
process, offers a promising method for processing end-of-life Hard Disk Drive (HDD) NdFeB
magnets by converting them into demagnetised powders while preserving microstructural
integrity. This study investigates the impact on hydrogenation temperature (room
temperature, 50°C, 75°C) on the recycling process at 4 bar hydrogen pressure and 2 hours.
Chemical composition was determined by ICP-OES, oxygen and hydrogen contents by LECO
analysis, phase identification by XRD with Rietveld refinement, and microstructure by SEMEDS.
Results indicate that reduced temperatures promote hydrogen absorption, diminish
oxidation, and produce finer particles characterised by typical intergranular fractures. XRD
confirmed the formation of Nd₂Fe₁₄BHₓ phases with decreasing hydrogen content at elevated
temperatures, along with an increased presence of Nd₂O₃ due to the exposure of reactive
surfaces. According to these results, HD at room temperature under 4 bar is optimal for the
effective and sustainable recycling of NdFeB magnets, eliminating the need for further heat
treatment.
Description
Keywords
Hydrogen Decrepitation, NdFeB Magnets