On the preparation of La(Fe,Mn,Si)13Hx polymer-composites with optimized magnetocaloric properties

• ΔTadΔTad value of bulk La(Fe,Mn,Si)13Hx obtained by direct measurements.
• MCE of loose, compacted and polymer bonded powder samples was investigated.
• Particle size, compaction pressure, type and amount of adhesive were optimized.
• Full dense composite material with preserved magnetocaloric properties was produced.
• The new composite material has higher ΔSmΔSm and ΔTadΔTad values than Gd and La(Fe,Co,Si)13.

A successful use of the magnetocaloric material in an active magnetic regenerator (AMR) requires its machining into heat exchangers with good mechanical and chemical stability. Most of the magnetocaloric materials currently available for room temperature application do not meet those requirements, they are brittle and are susceptible to corrosion. Adhesive-bonding techniques can provide mechanical stability, corrosion protection and net shaped modules in a single step manufacturing process. However, the magnetocaloric properties of the composite materials can be significantly lowered during this process e.g. due to improper adhesion, dilution, and compaction pressure. We report on a comprehensive study of the influence of powder particle size, adhesive type, adhesive concentration and compaction pressure on the magnetocaloric properties of polymer-bonded La(Fe,Mn,Si)13Hx material.