Controlled variation of parameters of magnetocaloric materials

Patent metadata

Field	Value
Publication number	US-2019198206-A1
Application number	US-201716328912-A
Country	US
Kind code	A1
Filing date	Aug 31, 2017
Priority date	Aug 31, 2016
Publication date	Jun 27, 2019
Grant date	—

Abstract

Described are a kit comprising at least two magnetocaloric materials having identical stoichiometry but different Curie temperature, a magnetocaloric regenerator comprising at least two magnetocaloric materials having identical stoichiometry but different Curie temperature and a process for producing at least two magnetocaloric materials having identical stoichiometry but different Curie temperature.

First claim

1 A kit, comprising:
A magnetocaloric materials,
wherein each of the Z magnetocaloric materials is a composition of formula (I):
(Mn x Fe 1−x ) 2+u P y Si v C z N r B w   (I),

wherein
0.3≤x≤0.7;
−0.12≤u≤0.10;
0.3≤y≤0.75;
0.25≤v≤0.7;
0≤z≤0.15;
0≤r≤0.1;
0≤w≤0.1;
(y+v+w)≤1.05;
(y+v+w+r)≥0.95;
wherein u, x, y, v, z, r and w are identical for each of the Z magnetocaloric materials,
wherein Z≥2, and
wherein a Curie temperature of each of the Z magnetocaloric materials differs from a Curie temperature of each of other Z-1 magnetocaloric materials by at least 0.5 K.

2 : The kit according to claim 1 ,
wherein each of the Z magnetocaloric materials comprises: (i) a phase having a hexagonal structure of composition M 2 X with a crystal lattice having space group P-62m in a weight fraction of from 80% to 100%, (ii) a phase having a cubic structure of composition M 3 X with a crystal lattice having space group Fm-3m in a weight fraction of from 0% to 20%, and (iii) a phase having a hexagonal structure of composition M 5 X 3 with a crystal lattice having space group P6 3 /mcm in a weight fraction of from 0% to 20%, wherein in each case, M denotes atoms of elements selected from the group consisting of Fe and Mn and X denotes atoms of elements selected from the group consisting of P, Si, C, N and B, wherein for each of the Z magnetocaloric materials, sum of weight fractions of phases (i), (ii) and (iii) is 100%, and wherein each of the Z magnetocaloric materials differs from each of the other Z-1 magnetocaloric materials by the weight fractions of at least two of the phases (i), (ii) and (iii).

3 : The kit according to claim 1 , wherein the Z magnetocaloric materials have Curie temperatures of from 220 K to 330 K.

4 : The kit according to claim 1 , wherein Z is from 3 to 100.

5 : A magnetocaloric regenerator comprising:
Z magnetocaloric materials, wherein each of the Z magnetocaloric materials is a composition of formula (I):
(Mn x Fe 1−x ) 2+u P y Si v C z N r B w   (I),

wherein 0.3≤x≤0.7; −0.12≤u≤0.10; 0.3≤y≤0.75; 0.25≤v≤0.7; 0≤z≤0.15; 0≤r≤0.1; 0≤w≤0.1; (y+v+w)≤1.05; (y+v+w+r)≥0.95; wherein u, x, y, v, z, r and w are identical for each of the Z magnetocaloric materials, wherein Z≥2, and wherein a Curie temperature of each of the Z magnetocaloric materials differs from a Curie temperature of each of other Z-1 magnetocaloric materials by at least 0.5 K.

6 : The magnetocaloric regenerator according to claim 5 , wherein the magnetocaloric regenerator comprises a cascade comprising the Z magnetocaloric materials, wherein Z≥3, and
wherein in the cascade, the magnetocaloric materials are arranged in succession by ascending or descending Curie temperature.

7 : The magnetocaloric regenerator according to claim 5 , wherein Z is from 3 to 100.

8 : The magnetocaloric regenerator according to claim 6 , wherein in the cascade, a temperature difference between two succeeding magnetocaloric materials is in each case from 0.5 K to 6K.

9 : A method, comprising:
manufacturing a magnetocaloric regenerator with the kit of claim 1 .

10 : A device, comprising the magnetocaloric regenerator according to claim 5 ,
wherein the device is selected from the group consisting of a refrigeration system, a climate control unit, an air conditioning device, a thermomagnetic power generator, a heat exchanger, a heat pump, a thermomagnetic actuator, and a thermomagnetic switch.

11 : A process for preparing Z magnetocaloric materials, wherein Z≥2, the process comprising:
(a) providing a mixture of precursors comprising atoms of elements iron, manganese, phosphorus, silicon and optionally one or more of elements carbon, nitrogen and boron;
(b) reacting the mixture to obtain a solid reaction product;
(c) optionally shaping of the solid reaction product to obtain a shaped solid reaction product;
(d) optionally exposing the solid reaction product or the shaped solid reaction product to an atmosphere comprising one or more hydrocarbons to obtain a carburized product;
(e) heat treatment of the solid reaction product or the shaped solid reaction product or the carburized product at a heat treatment temperature to obtain a heat treated product, wherein the heat treatment temperature in (e) in preparing each of the Z magnetocaloric materials is different from the heat treatment temperature in (e) in preparing each of other Z-1 magnetocaloric materials;
(f) cooling the heat treated product to obtain a cooled product; and
(g) optionally shaping of the cooled product,
wherein each of the Z magnetocaloric materials is a composition of formula (I):
(Mn x Fe 1−x ) 2+u P y Si v C z N r B w   (I),

wherein
0.3≤x≤0.7;
−0.12≤u≤0.10;
0.3≤y≤0.75;
0.25≤v≤0.7;
0≤z≤0.15;
0≤r≤0.1;
0≤w≤0.1;
(y+v+w)≤1.05;
(y+v+w+r)≥0.95;
wherein u, x, y, v, z, r and w are identical for each of the Z magnetocaloric materials, and
wherein a Curie temperature of each of the Z magnetocaloric materials differs from a Curie temperature of each of other Z-1 magnetocaloric materials by at least 0.5 K.

12 : The process according to claim 11 , wherein the mixture of precursors comprises one or more substances selected from the group consisting of elemental manganese, elemental iron, elemental silicon, elemental phosphorus, a phosphide of iron, a phosphide of manganese, and optionally one or more of elemental carbon, a carbide of iron, a carbide of manganese, a carbonizable organic compound, elemental boron, a nitride of iron, a boride of iron, a boride of manganese, ammonia gas and nitrogen gas.

13 : The process according to claim 11 , wherein the heat treatment temperature in (e) in preparing each of the Z magnetocaloric materials is from 1000° C. to 1200° C.

14 : The process according to claim 11 , wherein the heat treatment temperature in (e) in preparing each of the Z magnetocaloric materials differs from the heat treatment temperature in (e) in preparing each of the other Z-1 magnetocaloric materials by 50 K or less.

15 : The process according to claim 16 , wherein the process comprising reacting (b-2), and
in (b-2), transferring the liquid reaction product into the solid phase is carried out by quenching, melt-spinning or atomization.

16 : The process according to claim 11 , wherein the reacting (b) comprises:
(b-1) reacting the mixture in a solid phase to obtain the solid reaction product; and/or (b-2) transferring the mixture or the solid reaction product into a liquid phase and reacting it in the liquid phase to obtain a liquid reaction product, and transferring the liquid reaction product into a solid phase to obtain the solid reaction product.

Assignees

• Basf Se

Inventors

• Ter Maat Johan
• Misra Sumohan
• Van Asten David
• Reesink Bernard
• Hermes Wilfried
• Zeilinger Michael
• Seeler Fabian
• Schierle-Arndt Kerstin
• Brueck Ekkehard
• Nguyen Van Thang

Classifications

• C22C30/00

  Alloys containing less than 50% by weight of each constituent · CPC title

• H01F1/015 Primary

  Metals or alloys · CPC title

• F25B21/00

  Machines, plants or systems, using electric or magnetic effects · CPC title

• F25B2321/002

  by using magneto-caloric effects · CPC title

• H01F41/00

  Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties · CPC title