The sintering behaviour of LaFe11.0Si1.2Co0.8 powder produced by gas atomisation was examined to provide a basis for the application of powder metallurgical shaping technologies to magnetocaloric La(Fe,Si)13-alloys. The aim was to establish sintering parameters for attaining both high densification and good magnetocaloric properties for the investigated particle sizes <10 µm and <25 µm. Dilatometry measurements and sintering trials were carried out and density, microstructure and entropy change ΔS of the sintered samples were analysed. For the fine particles <10 µm, the lowest investigated sintering temperature 1150°C results in a relative density of 97%, a low α-Fe content and a high ΔS = −5 J kg−1 K−1 (ΔH=2 T). For powder <25 µm, a two-stage process is required to achieve similar properties.
FujiedaS, HasegawaY, FujitaA, Thermal transport properties of magnetic refrigerants La(FexSi1−x)13 and their hydrides, and Gd5Si2Ge2 and MnAs. J Appl Phys. 2004;95(5):2429–2431. doi:10.1063/1.1643774.
2.
LyubinaJ.Magnetocaloric materials for energy efficient cooling. J Phys D Appl Phys. 2017;50(5):53002, doi:10.1088/1361-6463/50/5/053002. doi: 10.1088/1361-6463/50/5/053002
3.
BalliM, JandlS, FournierP, Advanced materials for magnetic cooling: fundamentals and practical aspects. Appl Phys Rev. 2017;4(2):21305, doi:10.1063/1.4983612.
4.
FrancoV, BlázquezJS, IpusJJ, Magnetocaloric effect: from materials research to refrigeration devices. Prog Mater Sci. 2018;93:112–232. doi:10.1016/j.pmatsci.2017.10.005.
5.
LyubinaJ, GutfleischO, Kuz'minMD, La(Fe,Si)13-based magnetic refrigerants obtained by novel processing routes. J Magn Magn Mater. 2008;320(18):2252–2258. doi:10.1016/j.jmmm.2008.04.116.
6.
LiuJ.Optimizing and fabricating magnetocaloric materials. Chinese Phys B. 2014;23(4):47503, doi:10.1088/1674-1056/23/4/047503.
7.
WaskeA, GrunerME, GottschallT, Magnetocaloric materials for refrigeration near room temperature. MRS Bull. 2018;43(04):269–273. doi:10.1557/mrs.2018.69.
8.
WielandS, PetzoldtF.Powder-extrusion and sintering of magnetocaloric LaCe(FeMnSi)13 alloy. J Alloys Compd. 2017;719:182–188. doi:10.1016/j.jallcom.2017.05.168.
9.
WielandS, HeinSB.Metal powder extrusion of magnetocaloric heat exchanger structures. Proceedings of Euro PM 2018.
10.
MayerC, DubrezA, PierronnetM, Towards the large scale production of (La1-zCez)(Fe1-x-yMnySix)13Hn products for room temperature refrigeration. Phys Status Solidi C. 2014;11(5–6):1059–1063. doi:10.1002/pssc.201300650.
11.
PhejarM, Paul-BoncourV, BessaisL.Structural and magnetic properties of magnetocaloric LaFe13–xSix compounds synthesized by high energy ball-milling. Intermetallics. 2010;18(12):2301–2307. doi:10.1016/j.intermet.2010.07.022.
12.
KatterM, ZellmannV, BarczaA.Sintering behaviour and thermally induced decomposition and recombination (TDR) process of LaFeCoSi alloys. Fourth International Conference on Magnetic Refrigeration at Room Temperature, Baotou, China 2010.
13.
GermanRM.Sintering theory and practice. New York: John Wiley & Sons; 1996.
14.
ThümmlerF, OberackerR.An introduction to powder metallurgy. London: The Institute of Materials; 1993.
15.
DaiY, LiY, XuZ, Studying of doping boron and carbon in LaFe11.6Si1.4 magnetocaloric alloy by experimental and density-functional methods. J Alloys Compd. 2018;765:538–543. doi:10.1016/j.jallcom.2018.06.193.
16.
ZhangH, ShenBG, XuZY, Reduction of hysteresis loss and large magnetocaloric effect in the C- and H-doped La(Fe, Si)13 compounds around room temperature. J Appl Phys. 2012;111(7):7. doi:10.1063/1.3670608.
17.
DubrezA, ViknerP, MayerC, Magnetocaloric plate for a magnetic cooling element and method for the production thereof, block for magnetic cooling element comprising same and methods for the production thereof, and magnetic cooling element comprising said blocks. Patent WO2014170447A1. 2014.
18.
LiuJ, KrautzM, SkokovK, Systematic study of the microstructure, entropy change and adiabatic temperature change in optimized La–Fe–Si alloys. Acta Mater. 2011;59(9):3602–3611. doi:10.1016/j.actamat.2011.02.033.
19.
ChenX, ChenY, TangY.High-temperature phase transition and magnetic property of LaFe11.6Si1.4 compound. J Alloys Compd. 2011;509(34):8534, doi:10.1016/j.jallcom.2011.05.054.
20.
ZhangM, ZhangZ, HeC, Microstructure and magnetocaloric properties of LaFe11.8– xCoxSi1.2 Strip-cast Flakes. IEEE Trans Magn. 2015;51(11):1–4. doi:10.1109/TMAG.2015.2439299.
21.
LiuJ, ZhangP, DaiF, A new approach to prepare spherical La–Fe–Si–Co magnetocaloric refrigerant particles. Scr Mater. 2013;69(6):485–488. doi:10.1016/j.scriptamat.2013.06.009.
22.
GębaraP, PawlikP, ŠkorvánekI, Effect of Al content on the order of phase transition and magnetic entropy change in LaFe11Co0.8(Si1−xAlx)1.2 alloys. J Magn Magn Mater. 2014;372:201–207. doi:10.1016/j.jmmm.2014.07.053.
23.
LyubinaJ, SchäferR, MartinN, Novel design of La(Fe,Si)13 alloys towards high magnetic refrigeration performance. Adv Mater. 2010;22(33):3735–3739. doi:10.1002/adma.201000177.
