Microstructural evolution, magnetocaloric effect, mechanical and thermal properties of hot-pressed LaFe_11.6Si_1.4/Ce₂Co₇ composites prepared using strip-cast master alloy flakes

LaFe_11.6Si_1.4/Ce₂Co₇ composites were prepared using strip casting flakes (SC-flakes) and heat treated flakes (HT-flakes) by hot pressing, denoted as SC-HP and HT-HP, respectively. Subsequently, additional heat treatment was performed. The microstructure evolution, phase constitution, magnetocaloric and mechanical properties of these SC-HP and HT-HP samples over a large range of heat treatment temperatures and times were compared. Heat treatment at 1373 K for 12 h resulted in Ce and Co diffusion into La(Fe,Si)₁₃ particles. An increase of T_peak from 228 to 289 K and a large (–ΔS_M)^max increase from 1.89 to 5.01 J kg⁻¹ K⁻¹ (ΔH = 2 T) was observed in SC-HP samples. Combining hot pressing and heat treatment considerably reduces processing time. 90% of theoretical density, compressive strength greater than 450 MPa, large (–ΔS_M)^max of ~4.73–5.01 J kg⁻¹ K⁻¹ and good thermal conductivity (λ) above 5.5 Wm⁻¹K⁻¹ were also achieved, suggesting the practical use of such heat treated composites with attractive magnetocaloric, mechanical and thermal properties.