High temperature oxidation of rare earth permanent magnets. Part 1 – Microstructure evolution and general mechanism. (1st April 2018)

• Record Type: Journal Article
• Authors: Firdaus, Muhamad; Rhamdhani, M. Akbar; Rankin, W. John; Pownceby, Mark; Webster, Nathan A.S.; D'Angelo, Anita M.; McGregor, Kathie
• Is Part Of: Corrosion science. Volume 133(2018)
• Page Start: 374
• Page End: 385
• Publication Date: 2018-04-01
• Subjects: CEMS Conversion electron Mössbauer spectroscopy -- DSC Differential scanning calorimetry -- EDS Energy dispersive x-ray spectroscopy -- EoL End-of-Life -- EOZ External oxidation zone -- EPMA Electron probe micro analysis -- IOZ Internal oxidation zone -- RE Rare earth -- REE Rare earth elements -- REO Rare earth oxide -- REPM Rare earth permanent magnet -- SEM Scanning electron microscope -- TGA Thermogravimetric analysis -- TEM Transmission electron spectroscopy -- WDS Wavelength dispersive x-ray spectroscopy -- XRD X-ray diffraction; A. Rare earth elements -- B. EPMA -- B. SEM -- B. XRD -- C. Internal oxidation -- C. Oxidation; Corrosion and anti-corrosives -- Periodicals; 620.11223
• DOI: 10.1016/j.corsci.2018.01.040
• Languages: English
• ISSNs: 0010-938X

Abstract

Highlights: The microstructure evolution and mechanism of oxidation of (Nd, Pr)FeB magnet at 700–1500 K have been investigated. Three different oxidation microstructure evolutions were observed at 700–1000 K, 1000–1300 K and 1300–1500 K. The different microstructures formed during the oxidation have implications for devising strategies for the recycling/recovery process of (Nd, Pr)FeB magnets. Abstract: The microstructure evolution and mechanism of oxidation of (Nd, Pr)FeB magnet in the range 700–1500 K have been investigated. Bulk (10 × 5 × 5 mm) and powder samples (−150 μm) were oxidized under isothermal and non-isothermal conditions. DSC, XRD, high-temperature XRD, SEM and EPMA characterization techniques were utilized to investigate the general oxidation reactions, microstructure evolutions and phase transformations. Three different microstructure evolutions were observed in the temperature ranges 700–1000 K, 1000–1300 K and 1300–1500 K. The different product microstructures formed during the oxidation have implications for devising strategies for the recycling/recovery process of (Nd, Pr)FeB magnets.