Synthesis of Room-Temperature Magnetic Refrigerants Based on La-Fe-Si by a Novel Process

Magnetocaloric effect and H gradient in bulk La(Fe,Si)13Hy magnetic refrigerants obtained by HDSH

“…Bulk parts of La(Fe,Si) 13 H y were produced by HDSH, as described in previous work [19]. The process is divided in 3 basic steps: 3 In the cooling step after the sintering, the temperature is reduced to 773 K and the hydrogenation step is, thus, performed during two different time spans: 2 and 4 h; under pure H 2 atmosphere at pressures above 1 atm.…”

“…In this work, the recently reported [19] Hydrogen-Decrepitation-Sintering-Hydrogenation (HDSH) process was used to produce bulk parts of La(Fe,Si) 13 H y , varying the H content in order to cover a broader range of working temperatures. Samples from the same ingot were also produced by the conventional process and the resulting samples from both processes were then compared.…”

Peritectic Solidification Path of the La(Fe,Si)13 Phase in Dual-Phase Directionally Solidified La-Fe-Si Magnetocaloric Alloys

“…Other novel methods have been used, such as melt-spun to refine the prime a-Fe phase and powder metallurgy (HDSH) to insert H atoms; however, the alloys are prepared in powder and/or ribbon form. [17][18][19] Directional solidification has been used in the production of peritectic functional alloys and can tailor the microstructure, morphology, and oriented crystal growth, which has been reported for magnetic alloys such as Nd-Fe-B alloys. [20] Additionally, it can influence the solidification path by controlling the temperature gradient and growth rate, as reported in our previous research of dual-phase (c phase) Ni-Mn-In alloys.…”

Strain development during the phase transition of La(Fe,Mn,Si)13Hz

“…[17][18][19] During the decrepitation process, hydrogen diffuses first in the rare-earth rich phase, expanding it and generating cracks. Upon further hydrogenation, the hydrogen also diffuses through the main phase (e.g., for Nd-magnets, Nd 2 Fe 14 B), which also breaks apart.…”