| Title: | Microstructure refinement of Nd-Fe-B permanent magnets prepared via spark-plasma sintering |
|---|
| Authors: | ID Tomše, Tomaž, Institut "Jožef Stefan" (Author) |
|---|
| Files: |  URL - Source URL, visit https://ieeexplore.ieee.org/document/10568241
 PDF - Presentation file, download (9,55 MB)
MD5: 1ED5D705822B48505CCF58ED1E66EB4A
|
|---|
| Language: | English |
|---|
| Typology: | 1.01 - Original Scientific Article |
|---|
| Organization: |  IJS - Jožef Stefan Institute
|
|---|
| Abstract: | Sintered Nd-Fe-B-type permanent magnets are normally manufactured using a conventional powder-metallurgy approach. The limitations of such high-temperature, pressureless sintering methods include restricted control over the microstructure due to grain growth and constraints on the magnet’s geometry. The modern spark-plasma sintering (SPS) technique employs Joule heating and external pressure to offer lower consolidation temperatures and faster heating cycles compared to conventional approaches. As a result, the SPS has the potential for the rapid, low-temperature, net-shape manufacture of magnets. However, the nonequilibrium conditions associated with the SPS can lead to poor grain-boundary wetting and the formation of the soft-magnetic α-iron phase in samples prepared from anisotropic, microcrystalline Nd-Fe-B powders produced by standard procedures, i.e., strip casting, hydrogen decrepitation, and jet-milling. This study revealed that the absence of the Nd-rich grain-boundary film is related to the presence of hydrogen. Degassing the Nd-Fe-B powder before applying the SPS improved the distribution of the grain-boundary phase. Moreover, reducing the electrical currents in the sample during the SPS prevented the decomposition of the RE2Fe14B matrix, ensuring a favorable phase composition. Compared to magnets conventionally sintered at 1070 °C, the mean grain diameter of the SPS samples prepared at ≈880 °C was reduced by ≈33%. This reduction decreased the temperature coefficient of coercivity from -0.65 to -0.58%/°C. The coercivity increase measured for the SPS samples amounted to more than 15%, which was attributed to the combined effect of smaller grain size and reduced texture. |
|---|
| Keywords: | spark-plasma sintering, microstructure refinement |
|---|
| Publication status: | Published |
|---|
| Publication version: | Version of Record |
|---|
| Submitted for review: | 28.02.2024 |
|---|
| Article acceptance date: | 18.06.2024 |
|---|
| Publication date: | 26.07.2024 |
|---|
| Publisher: | IEEE |
|---|
| Year of publishing: | 2024 |
|---|
| Number of pages: | str. [1-6] |
|---|
| Numbering: | Vol. 60, iss. 8, article no. 2100406 |
|---|
| Source: | ZDA |
|---|
| PID: | 20.500.12556/DiRROS-21793  |
|---|
| UDC: | 537 |
|---|
| ISSN on article: | 1941-0069 |
|---|
| DOI: | 10.1109/TMAG.2024.3417611 |
|---|
| COBISS.SI-ID: | 199982339 |
|---|
| Copyright: | © 2024 The Authors. |
|---|
| Note: | Nasl. z nasl. zaslona;
Opis vira z dne 27. 6. 2024;
|
|---|
| Publication date in DiRROS: | 28.03.2025 |
|---|
| Views: | 951 |
|---|
| Downloads: | 416 |
|---|
| Metadata: |    |
|---|
|
:
|
Copy citation |
|---|
| | | | Share: |  |
|---|
Hover the mouse pointer over a document title to show the abstract or click
on the title to get all document metadata. |
