TY - GEN
T1 - Fundamental study of the hydrogen decrepitation process of Nd-Fe-B alloys
AU - Checa Fernández, B. L.
AU - Sarriegui, G.
AU - Burgos, N.
AU - Martín, J. M.
N1 - Publisher Copyright:
© European Powder Metallurgy Association (EPMA)
PY - 2021
Y1 - 2021
N2 - This work presents a comprehensive study of hydrogen decrepitation (HD) to obtain monocrystalline equiaxial Nd-Fe-B powder out of an agglomerated block made from gas atomized powder. Thermal analysis and X-ray diffraction were applied to analyze the hydrogenation kinetics of Nd2Fe14B and Nd-rich phases in the range of 20 to 300ºC. Scanning electron microscopy (SEM) was used to evaluate qualitatively the particle shape and size of HD powder. It was determined that increasing the temperature reduced gas absorption of Nd2Fe14B phase, which minimizes transgranular cracking. Simultaneously, the expansion of the Nd-rich phase caused by the hydride formation promoted intergranular fracture. The optimum temperature range for HD was 100-150ºC. In this range, the controlled fragmentation of the block resulted in large monocrystalline particles with a more equiaxial shape, which is a suitable precursor to develop anisotropic ultrafine powders by the hydrogenation, disproportionation, desorption, recombination (HDDR) process.
AB - This work presents a comprehensive study of hydrogen decrepitation (HD) to obtain monocrystalline equiaxial Nd-Fe-B powder out of an agglomerated block made from gas atomized powder. Thermal analysis and X-ray diffraction were applied to analyze the hydrogenation kinetics of Nd2Fe14B and Nd-rich phases in the range of 20 to 300ºC. Scanning electron microscopy (SEM) was used to evaluate qualitatively the particle shape and size of HD powder. It was determined that increasing the temperature reduced gas absorption of Nd2Fe14B phase, which minimizes transgranular cracking. Simultaneously, the expansion of the Nd-rich phase caused by the hydride formation promoted intergranular fracture. The optimum temperature range for HD was 100-150ºC. In this range, the controlled fragmentation of the block resulted in large monocrystalline particles with a more equiaxial shape, which is a suitable precursor to develop anisotropic ultrafine powders by the hydrogenation, disproportionation, desorption, recombination (HDDR) process.
UR - https://www.scopus.com/pages/publications/85149178771
M3 - Conference contribution
AN - SCOPUS:85149178771
T3 - Euro PM2021 Congress Proceedings
BT - Euro PM2021 Congress Proceedings
PB - European Powder Metallurgy Association (EPMA)
T2 - 2021 European Powder Metallurgy Congress and Exhibition, Euro PM 2021
Y2 - 18 October 2021 through 22 October 2021
ER -