Research on the Magnetocaloric Effect of Lanthanum Iron Silicon Alloy and Heusler Alloy Materials

Abstract

In today's advanced technological era, many technical fields cannot do without refrigeration technology. Refrigeration technology plays a crucial role in the development of human society. However, the widely used gas compression refrigeration technology in traditional refrigeration still has serious drawbacks, among which the most prominent ones are environmental pollution, low efficiency and high energy consumption. Therefore, a new type of refrigeration technology to replace the traditional gas compression refrigeration technology is needed. Currently, magnetic refrigeration technology is such a highly anticipated new technology. Magnetic refrigeration c ompared with traditional gas compression refrigeration, the magnetic refrigeration technology has many advantages, such as high efficiency, low energy consumption, low noise and environmental friendliness. In the past half century, significant breakthroughs have been made in the research of magnetic refrigeration technology. Many magnetic refrigeration materials with huge magnetocaloric effects have been discovered. Magnetic refrigeration has been widely applied in many research fields, and it is gradually entering people's lives in room-temperature refrigerators. Among the widely studied magnetocaloric effect materials, the NaZn13-type La(FeSi)13 alloy with a cubic structure is highly favored due to its low production cost, controllable Curie temperature TC , large MS , relatively stable chemical properties, and high saturation magnetization. Particularly, La(FeCoSi)13Bx alloy, as a new type of cubic NaZn13-type La(FeSi)13 series magnetic refrigeration working material, has a TC close to room temperature. It not only has a large MS but is also easy to be industrially synthesized, and is expected to become the standard working material for future room- temperature magnetic refrigerators. In the meanwhile, in Ni-Mn-(In, Sn, Ga, Sb) alloys, the magnetic- induced structural phase transition (martensite to austenite) is closely coupled with the magnetic order transition. At this time, the increase in structural order leads to a decrease in lattice entropy, resulting in adiabatic heat absorption. Moreover, since the contribution of lattice entropy at this time is dominant, the adiabatic heat absorption response caused by it is larger than that of traditional magnetic thermal materials. Among them, nickel-manganese-indium alloys are extensively studied magnetic thermal materials. By adjusting the content of indium, the martensite phase transition temperature (TM), Curie temperature (TC), and martensite Curie temperature (TM C) can be effectively controlled, thereby optimizing its magnetic heat performance. This paper starts from the practical application perspective, selects low-cost industrial purity raw materials, and improves the composition ratio of the existing magnetic refrigeration working material La(FeCoSi)13 alloy. That is, by partially replacing the La and Fe elements in the alloys system, the magnetocaloric effect of La(FeCoSi)13B0.25 alloys is studied. In the heusler alloy system research, the Ni50Mn50-xInx (x=14.5-16) range is selected to systematically explore the regulation laws of In content on the phase transition behavior, magnetic properties, and magnetic heat performance of the alloy, providing a theoretical basis for further component design and performance optimization of the alloy in this system.