Infiltration of Die-Upset Nd-Fe-B Magnets With Mischmetal Eutectic Alloys
| Autor: | Alexander Gabay, Wanfeng Li, George C. Hadjipanayis |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | IEEE Magnetics Letters. 9:1-5 |
| ISSN: | 1949-3088 1949-307X |
| Popis: | In recent years, infiltration of hot-deformed Nd-Fe-B magnets with liquid Nd- and Pr-rich alloys has been intensively studied as a cost-effective way of increasing the magnet coercivity $H_{{\text{c}}}$ and, ultimately, its maximum operating temperature. In this letter, a similar improvement is obtained through infiltration of commercial die-upset Nd-Fe-B magnets with eutectic alloys based on inexpensive Ce52La28Nd15Pr5 mischmetal (MM). After being infiltrated with 10 wt% of MM85Fe15, MM85Al 15, and MM70Cu30 alloys at 700 °C, the die-upset magnets exhibited an $H_{c}$ that was both higher and more temperature stable than before the treatment. For example, after infiltration with the MM85Al15 alloy, the room-temperature $H_{{\text{c}}}$ increased from 12.1 kOe to 17.8 kOe, whereas the absolute value of the $\Delta H_{\text{c}}/ H_{\text{c}}\Delta T$ between 27 °C and 100 °C decreased from 0.65%/°C to 0.54%/°C. Although the infiltration treatment reduces the maximum energy product of the magnets, this reduction becomes less significant at elevated temperatures, effectively disappearing at 150 °C to 175 °C. The microstructural effects of the treatment with MM-rich alloys are analyzed in the context of earlier studies involving Nd(Pr)-rich alloys. As of now, the improved $\Delta H_{\text{c}}/ H_{\text{c}}\Delta T$ in the infiltrated magnets still lacks a convincing, controversy-free explanation. |
| Databáze: | OpenAIRE |
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