36results about How to "Large magnetocaloric effect" patented technology

The invention discloses a gadolinium block material and a preparation method thereof. The preparation method comprises the following operation steps that firstly, metal gadolinium powder is used as the raw material and is ground through a mechanical milling method; secondly, the nanoscale gadolinium powder is placed in a die and pre-pressed in a pre-treatment chamber protected by argon; and thirdly, the die is placed in a spark plasma sintering device for sintering, and therefore the gadolinium block material is obtained. The preparation method is simple and practicable and can be used for preparing gadolinium block materials of different grain sizes; the average grain size of the material is adjustable within the range of 20-1000 nanometers, and the corresponding magnetothermal effect of the material within the grain size range is improved along with increase of the grain size of the prepared material.

The invention discloses an amorphous composite material not containing Fe, Co, Ni, the chemical formula is (Er 0.5 Cu 0.5 ) 100‑x al x , where 10≤x≤20. The present invention also provides the preparation method of the amorphous composite material, comprising the steps of: (1) putting metal Er, Cu and Al in an electric arc furnace in proportion, melting evenly, and obtaining a master alloy ingot after cooling; (2) ) re-melting the master alloy ingot into a master alloy melt, spraying the master alloy melt onto the surface of a rotating copper roller, and quenching to obtain a strip-shaped amorphous composite material. The invention also discloses the application of the amorphous composite material as a magnetic refrigerant material. Because the amorphous composite material of the present invention does not contain elements having strong antiferromagnetic coupling effects with Er such as Fe, Co, Ni, etc., it has more excellent magneto-caloric properties, and can realize larger magneto-caloric properties with less rare earth elements. Magnetocaloric effect, while saving material cost.

The invention relates to a high nuclear gadolinium cluster complex with a large magnetocaloric effect. The chemical formula is C110H82Gd10O56S22 which belongs to the triclinic system, and the space group is P-1. The preparation method comprises the steps of: placing gadolinium oxide, thiophene-3-carboxylic acid and water into a stainless steel reaction kettle and mixing uniformly; then, reacting for 72 hours at 150-170 DEG G; cooling to 20 DEG C to obtain block crystals; collecting the crystals and washing the crystals with water and ethanol; and vacuum drying to obtain the target product: high nuclear gadolinium cluster complex. The invention has the advantages that according to the preparation method based on large self-rotating ground state of gadolinium ions, weaker magnetic interaction among metals and larger metal ligand proportion, the high nuclear gadolinium cluster complex with the large magnetocaloric effect is prepared; the raw materials are simple and cheap to the benefit of large-scale production; and the complex has the large magnetocaloric effect, and has a huge potential application value in the aspect of magnetic refrigeration.

The invention discloses a lanthanum-iron-silicon-based hydride magnetic refrigerant, a preparation method of the lanthanum-iron-silicon-based hydride magnetic refrigerant and a magnetic refrigerator. The chemical formula of the lanthanum-iron-silicon-based hydride magnetic refrigerant is La1-aRa(Fe1-b-cMbSic)13Hd, wherein R represents one or a composition of a plurality types of the following rare earth elements: Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Sc and Y; a value range of a is 0 to 0.5; M represents one or a composition of a plurality of types of Ti, V, Cr, Mn, Co, Ni, Cu, Zn and Ga; a value range of b is 0.005 to 0.05; a value range of c is 0.069 to 0.162; and a value range of d is 0 to 2. The lanthanum-iron-silicon-based hydride magnetic refrigerant provided by the invention is formed into a block by adopting a hot pressing molding process, introduction of impurity constituents such as an adhesive and the like is avoided, a high thermomagnetic property is kept, the prepared magnetic refrigerant is excellent in mechanical property, the problem of reduction of mechanical properties of pulverization, frangibility and the like of a lanthanum-iron-silicon-based compound after hydrogenation is solved, and performance of the formed magnetic refrigerant can meet the use requirements of the magnetic refrigerator.

The present invention involves the technology field of magnetic phase transformation materials, and the invention has disclosed an MN absent -position MN replaced by BI 2 SB consequences and their preparation methods and applications, MN replaced by BI 2 The chemical formula of the SB conformity is: mn 2‑y SB 1‑x BI x Among them, Y is the absence of MN atoms, X represents the replacement amount of BI on SB, 0 <y <1, 0 <x ≤0.4;Then use the method of doping or element replacement to prepare the MN default MN replaced by BI 2 SB conformity alloy, regulates the first -level magnetic phase change and obtains a rich magnetic function in the alloy. 2 The SB consecutive is widely used in multiple fields such as magnetic refrigeration, magnetic storage, magnetic sensing, energy capture and energy exchange, and the preparation methods are simple and convenient, less energy consumption, low preparation costs, and suitable for industrial production.

The invention discloses a gadolinium complex with the high stability and the high magnetocaloric effect as well as a preparation method of the gadolinium complex. The chemical formula of the gadolinium complex with the high stability and the high magnetocaloric effect is [(Gd(azdc)(COOH))]n, wherein azdc is a 4,4-azodicarboxylic acid bivalent anion. The preparation method of the gadolinium complex comprises steps as follows: 1) adding H2azdc and a gadolinium chloride hexahydrate to a mixed solvent of DMF and distilled water, and then sequentially adding nitric acid and an LiOH solution to obtain a mixed liquid; 2) heating the mixed liquid at the temperature of 140 DEG C for reactions for 72 h, and then performing cooling, filtration and washing to obtain gadolinium complex crystals. The gadolinium complex and the preparation method have the advantages as follows: the preparation method of the gadolinium complex is simple in process and high in yield, and a way is provided for preparation of a molecule-based magnetic refrigerant with the high magnetocaloric effect; a prepared gadolinium complex refrigeration material is high in thermal stability, acid and base stability and chemical stability and has potential application values in the aspect of magnetic refrigeration.

The invention relates to a Mn with large magnetic entropy change and wide working temperature range 5 Ge 3 / (Mn,Fe) 5 Ge 3 Single crystal-like heterojunction room temperature magnetic refrigeration material and its preparation process. Using elemental Mn, Fe, P, Ge and Sn as raw materials, according to Mn 2‑x Fe x P 1‑y Ge y sn 12 (0.80≤x≤0.90,0.20≤y≤0.26) The raw materials are mixed and packaged in a quartz tube filled with Ar gas. After high temperature insulation, slow cooling, pouring of molten metal Sn and pickling separation, etc., For the first time, acicular Mn with a diameter of about 100-300 μm and a length of up to 1 cm was successfully prepared. 5 Ge 3 / (Mn,Fe) 5 Ge 3 Single crystal heterojunction room temperature magnetic refrigeration material. The room temperature magnetic refrigeration material has the advantages of large magnetic entropy change, wide working temperature range, large refrigeration capacity, no need for subsequent processing and acid corrosion resistance, and can be directly used as a room temperature magnetic refrigeration working medium.