Optimizing the microstructure of low-REM Nd-Fe-B sintered magnet using Tb3Co0.6Cu0.4HX addition

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989100%3A27240%2F18%3A10241395" target="_blank" >RIV/61989100:27240/18:10241395 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61989100:27350/18:10241395 RIV/61989100:27360/18:10241395

Výsledek na webu

—

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Optimizing the microstructure of low-REM Nd-Fe-B sintered magnet using Tb3Co0.6Cu0.4HX addition

Popis výsledku v původním jazyce

Nd-Fe-B permanent magnets are key materials in the electric power system and they are indispensable for the future success of environmentally beneficial technologies. The hysteretic characteristics of sintered Nd-Fe-B magnets are highly sensitive to their microstructure and composition of phases. This paper is focused on the coercivity enhancement of the near-stoichiometric Nd2Fe14B-based magnet by optimizing microstructure, which included processes of grain boundary diffusion and grain boundary structuring via the application of hydrogenated Tb3Co0.6Cu0.4Hx compound added to the powder mixture. The base alloy having the composition Nd-24.0, Pr-6.5, Dy-0.5, B-1.0, Al-0.2, Fe-balance was prepared by strip-casting technique and subjected to hydrogen decrepitation during heating to 270 oC in a hydrogen flow at a pressure of 0.1 MPa and subsequent 1 h dwell at this temperature. The Tb3Co0.6Cu0.4 alloy was prepared by arc melting of starting components in an argon atmosphere on a water-cooled copper bottom using a non-consumable tungsten electrode. The ingot was subjected to homogenizing annealing at 600 oC for 90 h and subsequent hydrogenation under the conditions used for the decrepitation of the strip-cast alloy. Hydrogenated Tb3Co0.6Cu0.4Hx compound and hydrogen-decrepitated strip-cast alloy were mixed and subjected to mechanical activation. The microstructure, phase composition and distributions of REM, Co, Cu for the prepared magnets were investigated by SEM/EDX method. It was found that the total REM content in the main magnetic (Nd, Pr, Tb)2Fe14B phase was TILDE OPERATOR+D91 30 wt.%. Intergranular Nd-rich phases differing by their Tb, Co, Cu contents were identified. Studies of the stability of structure-sensitive parameter, namely, the coercive force jHc of the sintered magnet prepared with 2 wt.% of Tb3Co0.6Cu0.4Hx addition to the low-temperature heat treatments show the increase in the coercive force up to 1480 kA/m. This phenomenon is not typical of sintered Nd-Fe-B magnets, which usually demonstrates the drop (or invariance) of the coercive force after low-temperature heat treatments at 350-450 oC. (C) 2018 TANGER Ltd., Ostrava.

Název v anglickém jazyce

Optimizing the microstructure of low-REM Nd-Fe-B sintered magnet using Tb3Co0.6Cu0.4HX addition

Popis výsledku anglicky

Nd-Fe-B permanent magnets are key materials in the electric power system and they are indispensable for the future success of environmentally beneficial technologies. The hysteretic characteristics of sintered Nd-Fe-B magnets are highly sensitive to their microstructure and composition of phases. This paper is focused on the coercivity enhancement of the near-stoichiometric Nd2Fe14B-based magnet by optimizing microstructure, which included processes of grain boundary diffusion and grain boundary structuring via the application of hydrogenated Tb3Co0.6Cu0.4Hx compound added to the powder mixture. The base alloy having the composition Nd-24.0, Pr-6.5, Dy-0.5, B-1.0, Al-0.2, Fe-balance was prepared by strip-casting technique and subjected to hydrogen decrepitation during heating to 270 oC in a hydrogen flow at a pressure of 0.1 MPa and subsequent 1 h dwell at this temperature. The Tb3Co0.6Cu0.4 alloy was prepared by arc melting of starting components in an argon atmosphere on a water-cooled copper bottom using a non-consumable tungsten electrode. The ingot was subjected to homogenizing annealing at 600 oC for 90 h and subsequent hydrogenation under the conditions used for the decrepitation of the strip-cast alloy. Hydrogenated Tb3Co0.6Cu0.4Hx compound and hydrogen-decrepitated strip-cast alloy were mixed and subjected to mechanical activation. The microstructure, phase composition and distributions of REM, Co, Cu for the prepared magnets were investigated by SEM/EDX method. It was found that the total REM content in the main magnetic (Nd, Pr, Tb)2Fe14B phase was TILDE OPERATOR+D91 30 wt.%. Intergranular Nd-rich phases differing by their Tb, Co, Cu contents were identified. Studies of the stability of structure-sensitive parameter, namely, the coercive force jHc of the sintered magnet prepared with 2 wt.% of Tb3Co0.6Cu0.4Hx addition to the low-temperature heat treatments show the increase in the coercive force up to 1480 kA/m. This phenomenon is not typical of sintered Nd-Fe-B magnets, which usually demonstrates the drop (or invariance) of the coercive force after low-temperature heat treatments at 350-450 oC. (C) 2018 TANGER Ltd., Ostrava.

Druh

D - Stať ve sborníku

CEP obor

—

OECD FORD obor

20501 - Materials engineering

Projekt

<a href="/cs/project/LTARF18031" target="_blank" >LTARF18031: Vývoj fyzikálně-chemických a inženýrských základů pro iniciaci inovativní úsporné technologie výroby vysoce výkonných permanentních magnetů na bázi (Nd,R)-Fe-B (R = Pr, Tb, Dy, Ho) s nízkým obsahem kovů vzácných zemin</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

METAL 2018 : conference proceedings : reviewed version : 27th International Conference on Metallurgy and Materials : May 23rd-25th 2018, Hotel Voronez I, Brno, Czech Republic, EU

ISBN

978-80-87294-84-0

ISSN

—

e-ISSN

neuvedeno

Počet stran výsledku

6

Strana od-do

1710-1715

Název nakladatele

Tanger

Místo vydání

Ostrava

Místo konání akce

Brno

Datum konání akce

23. 5. 2018

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

—