Monitoring of the hydrogen decrepitation process by acoustic emission
Mateusz Szymański , Jan Płowiec , Bartosz Michalski , Marcin Leonowicz
AbstractAcoustic Emission Testing (AT) was applied to monitor the Hydrogen Decrepitation (HD) process for two different NdFeB-type materials: sintered NdFeB magnet and annealed NdFeB ingot alloy. Acoustic signals of clearly different characteristics were acquired for these two materials, indicating different course of the HD process. Acoustic waves of high signal strength and high peak amplitude were generated for the sintered NdFeB magnet whereas acoustic signals of low energy and low intensity were registered for the annealed NdFeB alloy. These findings were supported by real-time visual observation of the HD process. The sintered NdFeB magnet decrepitates rapidly and its particles spatter for a longer distance comparing to the ingot NdFeB alloy. Different behavior of the investigated materials can be explained in relation to their structural properties and manufacturing history. Fine microstructure, homogenously distributed thin layer of the Nd-rich grain boundary phase and stress accumulated after fabrication process can be responsible for more intense characteristic of the HD process in case of the sintered NdFeB magnets.
|Journal series||Solid State Sciences, ISSN 1293-2558|
|Publication size in sheets||0.5|
|Keywords in English||NdFeB magnets; Powder technology; Acoustic testing|
|ASJC Classification||; ;|
|Score||= 70.0, 18-12-2019, ArticleFromJournal|
|Publication indicators||= 0; = 0; : 2017 = 0.787; : 2018 = 2.155 (2) - 2018=1.972 (5)|
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