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

The invention provides a Ni-Fe-Mn-Al alloy material, which has a chemical formula of Ni<50-x>Fe<x>Mn<50-y>Al<y> (2=<x=<9, 16<=y<=18). The preparation comprises the following steps: (1) weighting pure elements according to the ratio of the chemical formula, mixing the pure elements together; (2) placing the mixed material in a water-cooling copper crucible, and repeatedly smelting the mixed material through a conventional electric arch smelting method so as to obtain a uniform alloy casting ingot. The obtained polycrystalline casting ingot can be made into Ni<50-x>Fe<x>Mn<50-y>Al<y> rapidly-quenched strips with a certain texture through a melt quick quenching method. Compared to that of the conventional Ni-Mn base ferromagnetic shape-memory alloy, the binding strength among the crystals of the Ni-Fe-Mn-Al alloy is higher, and thus the mechanical property of the Ni-Fe-Mn-Al alloy is better. The Ni-Fe-Mn-Al alloy is prepared through a conventional method, the raw materials are cheap, and furthermore, the Ni-Fe-Mn-Al alloy has a strong magneto-thermal effect under a low magnetic field, so the Ni-Fe-Mn-Al alloy can be applied to the magnetic refrigeration field.

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 invention refers to the area of materials science and material physics and relates to a coated magnetic alloy material that can be used, for example, as a magnetic cooling material for cooling purposes. The object of the present invention is to provide a coated magnetic alloy material that exhibits improved mechanical and/or chemical properties. The object is accomplished by a magnetic alloy material having an Na Zn13-type crystalline structure and having a composition according to the formula Ra Fe100-a-x-y-z Tx My Lz, the surface of said alloy material being coated with a material comprising at least one element from the group of Al, Si, C, Sn, Ti, V, Cd, Cr, Mn, W, Co, Ni, Cu, Zn, Pd, Ag, Pt, Au or combinations thereof. The object is further achieved by a method in which the magnetic alloy material is coated by way of fluid phase processes.

The invention discloses thulium-based metal glass, a preparation method and an application thereof. Based on thulium as the major component, the formula of the thulium-based metal glass is shown in a formula (I), RE represents one or more rare earth elements selected from Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Er; T represents Co or Ni; a, b, c and d represent atomic percents of elements, wherein a is greater than or equal to 30 and less than or equal to 60, b is greater than or equal to 5 and less than or equal to 30, c is greater than or equal to 20 and less than or equal to 25, d is greater than or equal to 15 and less than or equal to 25, (a+b) is greater than or equal to 50 and less than or equal to 60, and (a+b+c+d) is equal to 100. According to the thulium-based metal glass disclosed by the invention, on the one hand, the amorphous forming ability can be modulated by changing RE and T, and on the other hand, the temperature interval of the thulium-based metal glass on magnetic transformation can be modulated to expand the magnetic transformation area, so that the thulium-based metal glass has great magnetocaloric effect in a wider temperature interval. TmaREbALcTd(I).

The invention provides a Ni-Mn-In-Co-Cu magnetic refrigeration alloy material and a preparation method and belongs to the technical field of magnetic materials. The chemical molecular formula of the Ni-Mn-In-Co-Cu magnetic refrigeration alloy material is Ni46MnxIn14Co3Cuy, and the sum of the mole numbers of the elements in the alloy is 100, wherein 33<=x<=36, and 1<=y<=4. According to the Ni-Mn-In-Co-Cu magnetic refrigeration alloy material and the preparation method, through raw material proportioning and vacuum arc repeated smelting, polycrystal cast ingot is prepared, annealing is conductedunder the high-purity inert gas shielding, rapid water cooling is then conducted, and then the Ni-Mn-In-Co-Cu magnetic refrigeration alloy block blank is prepared. When the alloy block is in a 1.5T magnetic field, the adiabatic temperature change range is 1.01-2.61 K. The magnetic alloy can obtain excellent adiabatic temperature change at nearby the indoor temperature, along with a huge magnetocaloric effect, the magnetic alloy can be used as a magnetic refrigeration work medium, and the magnetic alloy has a high magnetic refrigeration efficiency and a wide temperature domain work range.

The invention relates to a downfield-driven oriented Mn-Ni-Sn magnetic refrigeration alloy material, and a production method of a ribbon thereof, and belongs to the technical field of magnetic refrigeration alloy materials and ribbons thereof. The technical problem of reduction of the hysteresis loss of the magnetic refrigeration material through using a large externally applied magnetic field of magnetic refrigerating machines is solved, so the prepared magnetic refrigeration alloy material is widely used in a common rare earth permanent magnet range of 8-12 kOe, the material has a large refrigeration capacity at a temperature near room temperature, and the hysteresis loss influence is effectively reduced. The chemical molecular formula of the Mn-Ni-Sn magnetic refrigeration alloy material is MnxNiySnz, wherein x, y and z are the molar ratios of elements, x is not less than 43.0 and not more than 47.0, y is not less than 41.0 and not more than 45.0, z is not less than 10.0 and not more than 13.0, and the value of x + y + z is 100. The production method comprises the following steps: proportioning raw materials, preparing polycrystalline cast ingots, preparing a Mn-Ni-Sn magnetic refrigeration alloy ribbon blank through a melt fast quenching technology, preparing the Mn-Ni-Sn magnetic refrigeration alloy ribbon, and finally preparing a Mn-Ni-Sn magnetic refrigeration alloy ribbon sample.

A method is provided of making a magnetocaloric alloy composition comprising Ni, Co, Mn, and Ti, which preferably includes certain beneficial substitutional elements, by melting the composition and rapidly solidifying the melted composition at a cooling rate of at least 100 K/second (Kelvin/second) to improve a magnetocaloric property of the composition. The rapidly solidified composition can be heat treated to homogenize the composition and annealed to tune the magneto-structural transition for use in a regenerator.

The invention discloses a rare-earth-based high-entropy amorphous alloy material high in magnetocaloric effect. The molecular formula of the rare-earth-based high-entropy amorphous alloy is GdaCobAlcYdMe, wherein a, b, c, d and e represent the atom percentage content of the corresponding element, a is larger than or equal to 24.8 and smaller than or equal to 25, b is larger than or equal to 8 andsmaller than or equal to 25.4, c is larger than or equal to 24.8 and smaller than or equal to 25.4, d is larger than or equal to 5 and smaller than or equal to 15, e is larger than or equal to 10 andsmaller than or equal to 20, a+b+c+d+e is equal to 100, and M is one of Dy, Er and Ho. On the basis of a GdCoAly high-entropy amorphous alloy, M is used for replacing Y, the high-entropy amorphous alloy high in magnetocaloric effect is obtained, the alloy is stable in magnetocaloric performance, the magnetic variation temperature range is wide, and elements likely to volatile or oxidize are not included. In addition, the completely amorphous structure of the high-entropy amorphous alloy needs no crystallization heat treatment, the preparation process is simple, and the high-entropy amorphous alloy material has good magnetocaloric performance and has good application prospects in the technical field of magnetic refrigeration.

The invention belongs to the field of magnetic refrigeration, and particularly relates to a temperature-graded magnetic heating material and a preparation method thereof. The temperature-graded magnetic heating material comprises a Ni50Mn37Sn13 alloy film layer and a Ni50Mn35In15 alloy film layer. The phase change temperature of the Ni50Mn37Sn13 alloy film layer ranges from 295 K to 305 K. The phase change temperature of the Ni50Mn35In15 alloy film layer ranges from 301 K to 310 K. The thickness ratio of the Ni50Mn37Sn13 alloy film layer to the Ni50Mn35In15 alloy film layer is 1:3 to 3:1. According to the temperature-graded magnetic heating material and the preparation method thereof, by carrying out gradient design and preparation on the magnetic heating material, the work temperature zone of an existing magnetic heating material can be expanded, and the magnetic heating effect of the material can be improved; and a design rule and a regulating and control mechanism of the magnetic heating material are set up, and the gradient magnetic heating temperature material is pushed to develop towards application.

The invention discloses a crystal material. The crystal material is characterized in that a molecular formula of the crystal material is fd2Cu(SO4)2(OH)4, the crystal material belongs to a monoclinic system, space group is P21/c, cell parameters are shown as follows, wherein both alpha and gamma are equal to 90 degrees, beta is equal to 98.3-98.4, and Z is equal to 2. Magnetothermal effect of the crystal material is far greater than DGG, and the crystal material has good refrigerating performance. The invention further discloses a preparation method of the crystal material. The preparation method is simple, suitable for large-scale industrial production and wide in market prospect.

The invention belongs to the technical field of refrigeration, and discloses a ferromanganese-based magnetic refrigeration material with low heat stagnation and a preparation method and application thereof. The ferromanganese-based magnetic refrigeration material with low heat stagnation is prepared by sintering hard magnetic powder and mixed powder containing manganese and iron. The hard magneticpowder is composed of one or more of neodymium iron boron, samarium cobalt and samarium iron nitrogen hard magnets. The molar ratio of the mixed powder meets the chemical general formula MnxFey-xPaSib, and x is more than or equal to 0.9 and less than or equal to 1.3, y is greater than or equal to 1.9 and less than or equal to 2, a is more than or equal to 0.15 and less than or equal to 0.75, a and b meet the condition that a + b is equal to 1. Through adding hard magnetic powder into a mixed material containing manganese and iron, the block material with low heat stagnation and high density is prepared, the phase change temperature and heat stagnation of the magnetic refrigeration material are effectively changed by adding the hard magnetic powder, the block material with low heat stagnation, large magnetocaloric effect and high density is prepared, and the preparation method is beneficial to being applied to the technical field of room-temperature magnetic refrigeration.

The invention relates to an alloy magnetocaloric material for magnetic refrigeration at a room temperature as well as a preparation method and application thereof. A chemical general formula of the material is MnCo1-xTixGe, wherein x is 0.02 to 0.08; the atomic percentage of a manganese element in the material is 33.3 to 34.4 percent; the atomic percentage of a cobalt element is 32.8 to 33.3 percent; the atomic percentage of a titanium element is 0.6 to 2.7 percent; and the atomic percentage of a germanium element is 30.2 to 32.7 percent. During preparation, reactants are added into a vacuum electric arc furnace; the vacuum electric arc furnace is vacuumized to 10<4> Pa or below, and high-purity argon gas is introduced; samples are melted for 2 to 5 times repeatedly; samples are taken out and cooled, and then put into a high-temperature resistant quartz glass test tube for vacuumizing; the high-purity argon gas is introduced to clean the gas and then put into a furnace type box; and the samples are taken out and annealed to obtain a finished product. Compared with the prior art, the alloy magnetocaloric material disclosed by the invention is a secondary phase change material, and has the characteristics of small heat stagnation and large regulated temperature zones; moreover, the problem of the heat stagnation caused by a primary phase change material can be effectively avoided; and a preparation process has simple steps, the condition controllability is good, and the material has good application prospect.

The invention relates to a Mn5Ge3/(Mn, Fe)5Ge3 single-crystal-like heterojunction room-temperature magnetic refrigeration material with large magnetic entropy change and a wide working temperature zone and a preparation process thereof. Elementary substances Mn, Fe, P, Ge and Sn used as raw materials are mixed according to the component proportion of Mn<2-x>Fe<x>P<1-y>Ge<y>Sn12 (x is greater thanor equal to 0.80 and smaller than or equal to 0.90, and y is greater than or equal to 0.20 and smaller than or equal to 0.26) and packaged in a quartz tube filled with Ar gas. A needle-shaped Mn5Ge3/(Mn, Fe)5Ge3 single-crystal-like heterojunction room-temperature magnetic refrigeration material with the diameter of about 100-300 microns and the maximum length of 1cm is successfully prepared for the first time through the processes of high-temperature heat preservation, slow cooling, molten metal Sn pouring, acid pickling separation and the like. The room-temperature magnetic refrigeration material has the advantages of large magnetic entropy change, wide working temperature zone, large refrigeration capacity, no need of subsequent processing, acid corrosion resistance and the like, and canbe directly used as a room-temperature magnetic refrigeration working medium.