LaFeSi-based magnetic refrigeration material as well as preparation method and application thereof

Abstract

The invention discloses a LaFeSi-based magnetic refrigeration material as well as a preparation method and application thereof. The chemical formula of the refrigeration material is La1+aFe13-b-cCobSicHd and the refrigeration material comprises a NaZn13 structural phase, wherein a is greater than 0 but less than or equal to 1, b is greater than or equal to 0 but less than or equal to 1.2, c is greater than or equal to 1.0 but less than or equal to 1.8 and d is greater than or equal to 0 but less than or equal to 3. The preparation method comprises the following steps: preparing raw materials according to the chemical formula and smelting in the presence of high-purity inert gas to obtain an alloy ingot with uniform components; annealing the alloy ingot in the presence of high-purity inert gas and then quickly quenching to obtain the La(Fe, Co, Si)13-based block magnetic refrigeration material containing the NaZn13 structural phase; and furthermore, introducing hydrogen into the block magnetic refrigeration material. According to the block magnetic refrigeration material, the forming period of a magnetic thermal phase is obviously shortened. The material before hydrogenation needs not to be mechanically crushed to small particles, and the block can be fully hydrogenated to be saturated. The material has a huge magnetocaloric effect and low hysteresis, so that the material is an ideal near room-temperature magnetic refrigeration working material.

Description

technical field [0001] The invention relates to a magnetic material, in particular to a LaFeSi-based magnetic refrigeration material with giant magnetocaloric effect and its preparation method and application, belonging to the field of magnetic refrigeration material preparation. Background technique [0002] With the development of modern society, refrigeration technology plays a vital role in improving people's living standards and working environment. Refrigeration appliances such as refrigerators and air conditioners have entered every household. According to statistics, the annual energy consumption of the refrigeration industry accounts for more than 15% of the total energy consumption of the whole society. The highest efficiency of the gas compression refrigeration technology commonly used at present is only 25%, and has the disadvantages of polluting the environment, loud noise, and large volume. Therefore, exploring environmentally friendly, efficient and energy-sa...

AI Technical Summary

Problems solved by technology

It can be said that La(Fe,Si) 13 Magnetic refrigeration materials have shown great application prospects, but the formation of a single bulk NaZn 13 type structure La(Fe,Si) 13 Compounds need to be annealed at high temperature for seven days or even weeks, which not only wastes energy, but also has an extremely long production cycle, which greatly restricts its industrial application

Some studies have pointed out that the rapid solidification process can shorten the La(Fe,Si) 13 The preparation cycle of magnetic refrigeration materials, but the equipment used is more complicated and the shape is limited to very thin strips or sheets, and it is impossible to prepare bulk materials

In fact, La(Fe,Si) 13 The Curie temperature of the compound is around 200K, so it cannot be directly used in a room temperature magnetic refrigerator. Document 2 reports that Fe in the substitution compound of Co element can adjust La(Fe,Si) 13 The range from the Curie temperature to room temperature of the base compound, but in the literature La(FeCoSi) 13 Compounds also require long-term annealing to form a 1:13 phase with magnetocaloric effect; literature 3-4 reports that La(Fe,Si) 13 Doping H, C and other elements in the interstitial position of the compound can also adjust its Curie temperature to the room temperature range. According to literature 1, it is known that the positive ratio of La(Fe,Si) 13 The compound must be crushed into powder so that hydrogen atoms can easily enter the compound. The crushing process will introduce a large number of defects, resulting in a decrease in the magnetocaloric effect. It can be seen from literature 3 that the positive ratio La(Fe,Si) 13 The hydrogenation of the compound needs to be prepared into powder by mechanical crushing method, and the resulting room temperature La(Fe,Si) 13 The magnetocaloric effect of H magnetic refrigeration materials is significantly reduced

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