CN102881394B - La (Fe, Si) prepared by rare earth purification intermediate product 13base magnetic material, preparation method and purposes - Google Patents

Abstract

What the invention provides the impure LaCe reasonable offer of a kind of rare earth purification process intermediate product has NaZn ₁₃the La (Fe, Si) of type structure ₁₃base magnetic refrigerating material and its production and use, its chemical general formula is: La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _α.Preparation method comprises: using described LaCe alloy as raw material, by melting, the obtained La of annealing _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αmagnetic material.In LaCe alloy, the existence of impurity does not affect the generation of 1:13 phase and first order phase change feature, becomes the appearance of magnetic transition behavior, maintains huge magneto-caloric effect.With described LaCe reasonable offer La (Fe, Si) ₁₃base magnetic refrigerating material, reduces the dependence to high purity elemental rare earths material, reduces the preparation cost of material, and the magnetic refrigeration application for exploitation material has important practical usage.

Description

La (Fe, Si) prepared by rare earth purification intermediate product 13base magnetic material, preparation method and purposes

Technical field

The present invention relates to a kind of magnetic refrigerating material, particularly relate to a kind of La (Fe, Si) with the LaCe reasonable offer impure with rare earth purification process intermediate product of huge magneto-caloric effect ₁₃base magnetic refrigerating material and preparation method thereof and material applications.

Background technology

Refrigeration industry power consumption accounts for more than 15% of the total power consumption of society.Its Carnot's cycle efficiency of vapor compression refrigeration technology generally used at present is only up to about 25%, and the gas refrigerant used in vapor compression refrigeration can destroy atmospheric ozone layer and cause greenhouse effect.Refrigerating material and research and development Novel low-consumption, the high efficiency Refrigeration Technique of seeking pollution-free, environmental protection are that the world today needs the urgent problems solved.

Magnetic Refrigeration Technique has environmental protection, energy-efficient, reliable and stable feature, has caused worldwide extensive concern in the last few years.A few type high temp that the U.S., China, Holland, Japan find in succession and even room-temperature zone materials with the giant magnetocaloric effect have promoted the expectation of people to environmental protection magnetic Refrigeration Technique greatly, such as: Gd-Si-Ge, LaCaMnO ₃, Ni-Mn-Ga, La (Fe, Si) ₁₃based compound, MnAs based compound etc.The common feature of these novel giant magnetio-caloric effects materials is that magnetic entropy becomes all higher than conventional chamber temperature magnetic refrigerating material Gd, and phase transition property is one-level, and majority presents strong magnetocrystalline coupling characteristics, and magnetic phase transition is with the generation of significant crystal structure phase transformation.These new materials also show different material characteristicses, such as, and the Gd that Ames National Laboratory of the U.S. found in 1997 ₅(Si ₂ge ₂) alloy has huge magneto-caloric effect, adiabatic temperature becomes Δ T higher than 30% of simple substance rare-earth Gd, and magnetic entropy uprises in Gd 100%; But this kind of material often needs to purify further to raw material Gd in building-up process, the Gd purity that usual business is bought is 95-98at.%(atomic ratio), price 200 dollars/kilogram, the Gd prepared with business purity Gd ₅(Si ₂ge ₂) alloy do not have giant magnetio-caloric effects; If raw material Gd to be purified to>=99.8at.%(atomic ratio) synthesized by the Gd that goes out ₅(Si ₂ge ₂) side shows giant magnetio-caloric effects, and purity to the price of the Gd of>=99.8at.% is 4000 dollars/kilogram, considerably increases the preparation cost of material; Research also shows, in raw material impurity existence (as 0.43at.%C, 0.43at.%N, 1.83at.%O) or introduce a small amount of C element and all can make Gd ₅(Si ₂ge ₂) first order phase change characteristic disappear, giant magnetio-caloric effects also thereupon disappear (J.Magn.Magn.Mater.167, L179 (1997); J.Appl.Phys.85,5365 (1999)).In addition in a few class new material, MnAs based compound raw material are poisonous, and NiMn base Heusler alloy has large feature of hysteresis loss etc.

In the nearly a few class new materials found during the last ten years, accepted extensively in the world at present, that most possibly realize high temperature and even room-temperature zone magnetic refrigeration application is La (Fe, Si) ₁₃based compound, it is cheap that this alloy has the prices of raw and semifnished materials, and phase transition temperature, phase transition property, hysteresis loss can with features such as composition regulations, and near room temperature magnetic entropy uprises one times in Gd.The unit of multiple country, laboratory are one after another by La (Fe, Si) ₁₃base magnetic refrigerating material is used for prototype test, and such as: 2006, American National Space Technology Center (AstronauticsTechnologyCenter, AstronauticsCorporationofAmerica) is first by La (Fe, Si) ₁₃sill is used for prototype test, and PRELIMINARY RESULTS proves that its refrigerating capacity is better than Gd, and further, the said firm proves in the up-to-date the prototype test results of 2010: La (Fe, Si) ₁₃the room temperature refrigerating capacity of sill can reach 2 times of Gd.

Research shows, La (Fe, Si) ₁₃the phase transition property of based compound can change with the adjustment of component.Such as the Compound Phase change nature of low Si content is generally one-level, increase Curie temperature with Co content rises, first order phase change character weakens, and be transitioned into secondary gradually, hysteresis loss reduces gradually (second-order phase transistion does not have hysteresis loss), but due to the change of component, exchange interaction, magneto-caloric effect amplitude also declines thereupon.Being added with of Mn affects exchange interaction makes Curie temperature decline, and first order phase change character weakens, and hysteresis loss reduces gradually, and magneto-caloric effect amplitude also declines thereupon.On the contrary, it is found that, little rare-earth magnetic atom (such as Ce, Pr, Nd) substitutes La can strengthen first order phase change character, and hysteresis loss increases, and magneto-caloric effect amplitude increases.Also find: the introducing with the interstitial atom (such as C, H, B etc.) of little atomic radius can improve Curie temperature, makes magneto-caloric effect occur in higher warm area scope, such as, as molecular formula LaFe _11.5si _1.5h _αwhen the content of interstitial atoms H is increased to α=1.8 from α=0, phase transition temperature (peak temperature of magneto-caloric effect) rises to 350K from 200K.People expect to have the first order phase change La (Fe, Si) of giant magnetio-caloric effects ₁₃based compound is used for actual magnetic refrigeration application, and obtains desirable refrigeration.

Report showed in the past, La (Fe, Si) ₁₃based compound all uses business-like simple substance element at preparation process middle rare earth raw material.People know, containing abundant La, Ce rare earth element in the earth's crust, Ce elemental abundance is the highest, be secondly Y, Nd, La etc., and the natural component of many rare earth ores is La to be 20-30%, Ce be 40-60% and other rare earth and non-lucium.La and Ce that the LaCe alloy ratio obtaining about 1:2 ratio in purification process obtains simple substance is respectively much easier.The price of commercialization LaCe alloy is also cheaply many than commercialization simple substance element La, Ce.If using business-like LaCe alloy as raw material, can prepare and there is NaZn ₁₃the hot La (Fe, Si) of huge magnetic of structure ₁₃based compound, the magnetic refrigeration application for exploitation material will have important practical usage.

Summary of the invention

For contributing to understanding the present invention, define some terms below.Term defined herein has the implication that those of ordinary skill in the related art of the present invention understand usually.

Unless otherwise indicated, term LaFe used herein _13-xm _xcorresponding " NaZn ₁₃type structure " or " 1:13 structure " refer to that space group is a kind of structure.Fe atom occupies two brilliant position 8b (Fe respectively with 1:12 ratio ⁱ) and 96i (Fe ^iI) position.La and Fe ⁱatom composition CsCl structure.Wherein La atom is by 24 Fe ^iIatom surrounds, Fe ⁱatom is combined into icosahedral 12 Fe ^iIatom surrounds, each Fe ^iIthe Fe of 9 arest neighbors is had around atom ^iIatom, 1 Fe ⁱatom and a La atom.For LaFe _13-xm _x(M=Al, Si) compound, neutron diffraction experiment shows: 8b position is occupied by Fe atom completely, and M atom and remaining Fe atom occupy at random on 96i position.

One object of the present invention is, provides La (Fe, Si) prepared by a kind of rare earth purification intermediate product ₁₃base magnetic material.Another object of the present invention is, provides one rare earth purification intermediate product to prepare La (Fe, Si) ₁₃the method of base magnetic material.Another object of the present invention is, provides a kind of La (Fe, Si) comprising rare earth purification intermediate product and prepare ₁₃the magnetic refrigeration machine of base magnetic material.Another object of the present invention is, provides La (Fe, Si) prepared by a kind of rare earth purification intermediate product ₁₃base magnetic material is manufacturing the application in refrigerating material.

For foregoing invention object, the invention provides following technical scheme:

On the one hand, the invention provides the La (Fe, Si) prepared with rare earth purification intermediate product ₁₃base magnetic material, wherein:

Described magnetic material has NaZn ₁₃type structure, its chemical general formula is La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _α, wherein,

R is selected from the one or more combination in Pr and Nd element, such as one or both,

A is selected from the one or more combination in C, H and B element, such as one or more,

The scope of x is: 0<x≤0.5,

The scope of y is: 0≤y≤0.5, and x+y<1,

The scope of p is: 0≤p≤0.2,

The scope of q is: 0≤q≤0.2,

The scope of z is: 0.8<z≤1.8,

The scope of α is: 0≤α≤3.0;

Described rare earth purification intermediate product is business-like impure LaCe alloy, be preferably the impure LaCe alloy with natural proportion extracted from light rare earth ore deposit in rare earth purification process, preferably, purity >=the 95at% of described LaCe alloy, be preferably 95-98at.%(wherein, described at.% represents atomic percent), in alloy, La:Ce atomic ratio is its natural proportion in light rare earth ore deposit, be preferably 1:1.6-1:2.3, dopant species in alloy includes but not limited to: Pr, Nd, Fe, Si, Cu, Ni, Zn, Th, Y, Mg, Ca, C, H, one or more in O.

In one embodiment of the present invention, the scope of described α is: 0≤α≤0.8.

According to magnetic material provided by the invention, wherein, also containing one or more elements be selected from Cu, Ni, Zn, Th, Y, Mg, Ca, O in described magnetic material, these elements are introduced by impure LaCe alloy.When needing the material of preparation to be only made up of La, Ce, Fe, Si, owing to adopting impure LaCe reasonable offer, the impurity existed in alloy will inevitably together be introduced, so now Pr, Nd, C, H tetra-kinds of elements also become impurity for alloy, then the impurity contained in described magnetic material is: one or more in Pr, Nd, C, H, Cu, Ni, Zn, Th, Y, Mg, Ca, O.

Further, according to aforesaid magnetic material, wherein, the magnetic entropy variate of described magnetic material under 0-5T changes of magnetic field is 5.0-50.0J/kgK, and transition temperature area is positioned at 10-400K.

On the other hand, the invention provides a kind of method preparing described magnetic material, wherein, said method comprising the steps of:

1) by La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αthe chemical formula preparation raw material of magnetic material, or when the A in chemical formula comprises protium, by chemical formula preparation raw material in addition to hydrogen, La and Ce element in raw material is provided by impure LaCe alloy, preferably provided by the impure LaCe alloy with natural proportion extracted from light rare earth ore deposit in rare earth purification process, preferably, in LaCe alloy, La element insufficient section is supplemented by simple substance La; Other elements in this chemical formula to be selected containing the material of this element as raw material according to the conventional method of this area, make the ratio of the amount of the ratio of the amount of all elements in raw material and each elemental substance and all elements in this chemical formula and each elemental substance identical;

2) utilize electric arc melting technology to prepare sample, the raw material prepared is put into arc furnace, vacuumize in step 1), with argon purge, and melting under argon shield, obtain alloy pig;

3) by step 2) melted alloy pig vacuum annealing, then at liquid nitrogen or quenching-in water, thus prepare there is NaZn ₁₃the La of structure _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αmagnetic material;

Wherein, when the A in chemical formula comprises protium, described method also comprises step 4): the material that step 3) is obtained is divided into powder, at hydrogen annealing.

Further, according to aforesaid preparation method, in the chemical formula of described magnetic material:

R is selected from the one or more combination in Pr and Nd element;

A is selected from the one or more combination in C, H and B element;

The scope of x is: 0<x≤0.5;

The scope of y is: 0≤y≤0.5, and x+y<1;

The scope of p is: 0≤p≤0.2;

The scope of q is: 0≤q≤0.2;

The scope of z is: 0.8<z≤1.8;

The scope of α is: 0≤α≤3.0.

In one embodiment of the present invention, the scope of described α is: 0≤α≤0.8.

Further, according to aforesaid preparation method, wherein, described LaCe alloy can business obtain, its purity is >=95at%, is preferably 95-98at.%, and in alloy, La:Ce atomic ratio is its natural proportion in light rare earth ore deposit, be preferably 1:1.6-1:2.3, the dopant species in alloy includes but not limited to: one or more in Pr, Nd, Fe, Si, Cu, Ni, Zn, Th, Y, Mg, Ca, C, H, O.

Further, according to preparation method provided by the invention, wherein, in described raw material, when A comprises C element, C element can be provided by FeC alloy.Because the C fusing point of simple substance is very high, be difficult to be melting into inside alloy, Fe, C of simple substance can be utilized in advance to prepare FeC alloy, to introduce C element with guaranteeing q.s, now owing to also containing Fe element in FeC alloy, need suitably to reduce the simple substance Fe added, make the proportioning of the various elements added still meet the atom ratio of magnetic material chemical formula.Similarly, when A comprises B element, B element can be provided by FeB alloy.

Further, according to preparation method provided by the invention, wherein, other materials in described raw material except LaCe alloy, as La, Pr, Nd, Fe, FeC, FeB, Co, Mn, Si, B, purity is all greater than 98wt%.

Further, according to aforesaid preparation method, wherein, described step 2) can comprise: the raw material prepared in step 1) is put into arc furnace, is evacuated to vacuum degree and is less than 1 × 10 ^-2pa, is greater than high-purity argon gas cleaning furnace chamber 1-2 time of 99wt%, is filled with this argon gas afterwards to 0.5-1.5 atmospheric pressure, Arc, acquisition alloy pig in furnace chamber by purity, melt back 1-6 time at 1500-2500 DEG C of each alloy pig.

Further, according to aforesaid preparation method, wherein, described step 3) can comprise: by step 2) melted alloy pig 1000-1300 DEG C, vacuum degree is less than 1 × 10 ^-3anneal under the condition of Pa 3-60 days, and then at liquid nitrogen or quenching-in water, thus to prepare principal phase be NaZn ₁₃the La of structure _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αmagnetic material.

Further, according to aforesaid preparation method, wherein, described step 4) can comprise: the material that step 3) is obtained is divided into powder, at hydrogen annealing, thus prepares La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αhydride; Preferably, the amount of substance by regulating Hydrogen Vapor Pressure, annealing temperature and time to control the hydrogen entered in alloy.

Further, according to aforesaid preparation method, wherein, described step 4) can comprise: the irregular powder that particle diameter is less than 2mm is made in material segmentation step 3) obtained, put into that purity is greater than 99wt%, pressure is 0-100 atmospheric hydrogen, the pressure of hydrogen is preferably 10 ^-4-100 atmospheric pressure, 0-600 DEG C of annealing 1min to 10 day, annealing preferably carried out 1 minute to 3 days at 100-350 DEG C, thus prepares La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _zthe hydride of A α.

Again on the one hand, the invention provides a kind of magnetic refrigeration machine, the magnetic material that described refrigeration machine comprises magnetic material provided by the invention or obtains according to method provided by the invention.

Another aspect, the invention provides described magnetic material or is manufacturing the application in refrigerating material according to the magnetic material that method provided by the invention obtains.

Compared with prior art, advantage of the present invention is:

1) the present invention prepares La (Fe, Si) using the LaCe alloy that the intermediate product of rare earth purification process is impure as raw material ₁₃base materials with the giant magnetocaloric effect.Containing abundant La, Ce rare earth element in the earth's crust, and the natural component of many rare earth ores all comprises Ce and other rare earth, the non-lucium of La, 40-60% of 20-30%.La and Ce that the LaCe alloy ratio obtaining about 1:2 ratio in purification process obtains simple substance respectively will be easy to many.So, prepare La (Fe, Si) with LaCe alloy as raw material ₁₃based compound, reduces the dependence to high purity elemental rare earths material, reduces the preparation cost of material, and the magnetic refrigeration application for exploitation material has important practical usage.

2) La (Fe, Si) for preparing of the present invention ₁₃in base magnetic material, do not affect NaZn by the impurity (as: Pr, Nd, Fe, Si, Cu, Ni, Zn, Th, Y, Mg, Ca, O, C, H etc.) introduced in business-like LaCe alloy ₁₃the generation of phase and first order phase change feature, become the appearance of magnetic transition behavior, maintain huge magneto-caloric effect.This point and famous materials with the giant magnetocaloric effect Gd ₅si ₂ge ₂situation completely different, Gd ₅si ₂ge ₂in alloy, the existence of impurity and introducing (as: C, H, O, Fe, Co, Ni, Cu, Ga, Al etc.) can make first order phase change feature weaken or disappear, and giant magnetio-caloric effects also disappears (J.Magn.Magn.Mater.167, L179 (1997) thereupon; J.Appl.Phys.85,5365 (1999)).

Accompanying drawing explanation

Below, describe embodiments of the invention in detail by reference to the accompanying drawings, wherein:

Fig. 1 is the La that embodiment 1 obtains _0.7ce _0.3fe _11.6si _1.4c _yxRD spectral line under (y=0.2,0.3) sample room temperature.

Fig. 2 is the La that embodiment 1 obtains _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Fig. 3 is the La that embodiment 1 obtains _0.7ce _0.3fe _11.6si _1.4c _ythe magnetization curve (MH curve) of field process is risen under (y=0.2,0.3) sample different temperatures.

Fig. 4 is La obtained in embodiment 1 _0.7ce _0.3fe _11.6si _1.4c _ythe lower magnetic entropy of (y=0.2,0.3) sample different magnetic field change becomes Δ S to the dependence of temperature.

Fig. 5 is the La that embodiment 2 obtains _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4xRD spectral line under (x=0.04,0.06,0.08) sample room temperature, wherein marking * peak is unknown dephasign.

Fig. 6 is the La that embodiment 2 obtains _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4(x=0.04,0.06,0.08) sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Fig. 7 a-c and Fig. 7 d is the La that embodiment 2 obtains _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4the magnetization curve (MH curve) rising field process under (x=0.04,0.06,0.08) sample different temperatures and Arrott figure (Fig. 7 d) derived by MH curve (Fig. 7 a, b, c).

Fig. 8 is the La that embodiment 2 obtains _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4the lower magnetic entropy of (x=0.04,0.06,0.08) sample different magnetic field change becomes Δ S to the dependence of temperature.

Fig. 9 is the La that embodiment 3 obtains _0.95-yce _0.05pr _yfe _11.5si _1.5xRD spectral line under (y=0.1,0.5) sample room temperature, wherein marking * peak is unknown dephasign.

Figure 10 is the La that embodiment 3 obtains _0.95-yce _0.05pr _yfe _11.5si _1.5(y=0.1,0.5) sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Figure 11 is the La that embodiment 3 obtains _0.95-yce _0.05pr _yfe _11.5si _1.5(y=0.1,0.5) sample magnetic entropy under 0-5T changes of magnetic field becomes Δ S to the dependence of temperature.

Figure 12 is the La that embodiment 4 obtains _0.8ce _0.2fe _11.4si _1.6b _αxRD spectral line under (α=0,0.2 and 0.4) sample room temperature, wherein marking * peak is unknown dephasign.

Figure 13 is the La that embodiment 4 obtains _0.8ce _0.2fe _11.4si _1.6b _α(α=0,0.2 and 0.4) sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Figure 14 is the La that embodiment 4 obtains _0.8ce _0.2fe _11.4si _1.6b _α(α=0,0.2 and 0.4) sample magnetic entropy under 0-1T changes of magnetic field becomes Δ S to the dependence of temperature.

Figure 15 is the La that embodiment 5 obtains _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _yxRD spectral line under (y=0.9,1.8) sample room temperature, wherein marking * peak is unknown dephasign.

Figure 16 is the La that embodiment 5 obtains _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _y(y=0.9,1.8) sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Figure 17 is the La that embodiment 6 obtains _0.7ce _0.3fe _11.5si _1.5c _0.2h _0.45sample: pyromagnetic (M-T) curve under (a) 0.02T magnetic field; B under () 0-5T changes of magnetic field, magnetic entropy becomes Δ S to the dependence of temperature.

Figure 18 is the La that embodiment 6 obtains _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05h _0.55sample: pyromagnetic (M-T) curve under (a) 0.02T magnetic field; B under () 0-5T changes of magnetic field, magnetic entropy becomes Δ S to the dependence of temperature.

Figure 19 is the La that embodiment 7 obtains _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4xRD spectral line under sample room temperature, unknown dephasign is by No. * mark.

Figure 20 is the La that embodiment 7 obtains _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Figure 21 is the La that embodiment 7 obtains _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4sample magnetic entropy under 0-5T changes of magnetic field becomes Δ S to the dependence of temperature.

Figure 22 is the La that embodiment 8 obtains _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9xRD spectral line under sample room temperature, unknown dephasign is by No. * mark.

Figure 23 is the La that embodiment 8 obtains _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9sample pyromagnetic (M-T) curve under 0.02T magnetic field.

Figure 24 is the La that embodiment 8 obtains _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9sample magnetic entropy under 0-5T changes of magnetic field becomes Δ S to the dependence of temperature.

Embodiment

Referring to specific embodiment, the present invention is described.It will be appreciated by those skilled in the art that these embodiments only for illustration of object of the present invention, its scope do not limited the present invention in any way.

Raw materials usedly in the embodiment of the present invention be:

1) business-like LaCe alloy, purchased from rare earth International Trading Company Ltd of Inner Mongol Baogang, purity has two kinds, the LaCe alloy purity used in embodiment 1 and embodiment 2 is: 97.03at.%, La, Ce atomic ratio: 1:1.88, the Pr of impurity content: 0.05at.%, the Nd of 0.05at.%, the Cu of the Si of the Fe of 0.71at.%, 0.24at.%, 0.11at.%, the Ni of 0.05at.%, the O of the Zn of the Th of 0.002at.%, 0.63at.%, 1.14at.%; The LaCe alloy purity used in embodiment 3 to embodiment 7 is: 95.91at.%, La, Ce atomic ratio: 1:2.24, the Fe of the Nd of the Pr of impurity content: 0.07at.%, 0.07at.%, 0.92at.%, the Si of 0.35at.%, the Th of the Ni of the Cu of 0.27at.%, 0.13at.%, 0.003at.%, the O of the Zn of 0.91at.%, 1.37at.%.

2) other raw material and purity thereof are respectively: simple substance La(purity 99.52wt%), simple substance Pr(98.97wt.%), simple substance Nd(98.9wt.%), purchased from Hunan distillation rare-earth metal material Co., Ltd, Fe(99.9wt%) purchased from Beijing Non-Fervoous Metal Inst..FeC(99.9wt%, Fe, C weight ratio: 95.76wt%Fe:4.24wt%C), the Fe melting being 99.9wt% by simple substance C and purity forms, Si(99.91wt%), purchased from Beijing Non-Fervoous Metal Inst..FeB alloy (99.9wt.%, Fe, B weight ratio are 77.6wt%:22.4wt%), purchased from BeiJing ZhongKe Sanhuan High-Tech Joint-stock Co., Ltd.Co(99.97wt%), purchased from Beijing Non-Fervoous Metal Inst..Mn(99.8wt.%), purchased from Beijing dicyclo chemical reagent factory.(above (1) and (2) two class raw materials are all block);

3) arc furnace used is that Beijing WuKe opto-electrical Technology Co., Ltd produces, model: WK-II type non-consumable arc furnace, Cu target X-ray diffractometer is that Rigaku company produces, model is RINT2400, superconductive quantum interference vibrating specimen magnetometer (MPMS(SQUID) VSM), for QuantumDesign(USA) company's production, model is MPMS(SQUID) VSM.

embodiment 1: preparation La _0.7 ce _0.3 fe _11.6 si _1.4 c _y (y=0.2,0.3) two kinds of magnetic materials

The present embodiment provides prepares La by chemical formula _0.7ce _0.3fe _11.6si _1.4c _ythe instantiation of (y=0.2,0.3) magnetic material, preparation technology is:

1) by La _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) chemical formula batching, raw material is impure LaCe alloy and Fe, Si, La and FeC, wherein, simple substance La is used for the part of La deficiency in supplementary LaCe alloy, and FeC alloy is used to provide C, due in FeC alloy also containing Fe element, need suitably to reduce the simple substance Fe added, make the proportioning of the various elements added still meet the atom ratio of magnetic material chemical formula;

2) by the raw material mixing in step 1), put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 2 times with the high-purity argon gas that purity is 99.996wt%, being filled with purity afterwards in furnace chamber is 99.996wt% high-purity argon gas to atmospheric pressure, Arc (after Arc, raw material are just molten becomes alloy together), obtain alloy pig, each alloy spindle melt back 4 times, smelting temperature is 2000 DEG C, after melting terminates, in copper crucible, cooling obtains cast alloy ingot;

3) by step 2) in the cast alloy ingot for preparing wrap with molybdenum foil respectively, be sealed in high vacuum (1 × 10 ^-4pa) in quartz ampoule, anneal 30 days at 1080 DEG C, break quartz ampoule Quenching in liquid nitrogen, obtain and there is NaZn ₁₃the La of type structure _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) sample.

performance test:

One, utilize Cu target X-ray diffractometer to determine room temperature X-ray diffraction (XRD) collection of illustrative plates of sample, as shown in Figure 1, result shows La _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) two samples are clean NaZn ₁₃type phase structure, this kind of system is especially mixed the α-Fe dephasign the most easily occurred in C system and is not all occurred in these 2 samples, shows that the existence of impurity in LaCe alloy raw material does not affect NaZn ₁₃the formation of phase and growing up.

Two, on superconductive quantum interference vibrating specimen magnetometer, La is measured _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) sample pyromagnetic (M-T) curve under 0.02T magnetic field, as shown in Figure 2, can find out, temperature lag is very little, is increased to y=0.3 Curie temperature T with C content from y=0.2 _c212K is risen to from 200K.

At MPMS(SQUID) VSM determines La _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) magnetization curve (MH curve) of field process is risen under sample different temperatures, be shown in Fig. 3, on MH curve, the appearance of remarkable flex point shows the existence becoming magnetic transition behavior from paramagnetic to ferrimagnetic state of induced by magnetic field, show that the existence of impurity in LaCe alloy raw material does not affect the generation of 1:13 phase, do not affect the appearance becoming magnetic transition behavior simultaneously, ensure that the large magneto-caloric effect of material yet.

According to Maxwell relation: $\mathrm{\&Delta;S}(T,H)=S(T,H)-S(T,0)={\&Integral;}_0^H{\left(\frac{\&PartialD;M}{\&PartialD;T}\right)}_H\mathrm{dH},$ Δ S can be become from isothermal magnetization curve calculation magnetic entropy.Fig. 4 illustrates La _0.7ce _0.3fe _11.6si _1.4c _y(y=0.2,0.3) Δ S under different magnetic field, to the dependence of temperature, can find out, Δ S peak shape is along with the increase in magnetic field is to high-temperature region asymptotic expansion, and spike heel platform, this is La (Fe, Si) ₁₃the characteristic feature of base first order phase change system, derives from the change magnetic transition behavior of the above induced by magnetic field of Curie temperature.Δ S peak shape demonstrates the existence of the first order phase change characteristic sum change magnetic transition behavior of system further, show that the existence of impurity in LaCe alloy raw material does not affect the generation of 1:13 phase further, do not affect the appearance becoming magnetic transition behavior, ensure that the large magneto-caloric effect of material yet.There are some researches show, the appearance of Δ S spike produces due to the two-phase coexistent of first order phase change process, is the illusion that there is not thermal effect, the Δ S flat reaction essence of magneto-caloric effect.Y=0.2,0.3 sample, under 0-5T changes of magnetic field, Δ S platform is respectively 28.7J/kgK, 25.1J/kgK, the magnetic entropy being all significantly higher than conventional chamber temperature magnetic refrigerating material Gd becomes (under 5T magnetic field, magnetic entropy becomes 9.8J/kgK), halfwidth is 19.4K, 20.4K respectively, and refrigerating capacity is 508.8J/kg, 462.8J/kg respectively.The magnetic entropy of the Gao Erkuan platform that flattens is that Ericsson type magnetic refrigerator device needs especially, and the magnetic refrigeration application for reality is significant.

Conclusion: the present embodiment can confirm with technical pure LaCe alloy for raw material, by described preparation technology, can prepare and have NaZn ₁₃the La (Fe, Si) of type crystal structure ₁₃base carbide, in LaCe alloy raw material, the existence of impurity does not affect NaZn ₁₃the formation of phase and growing up, becomes magnetic transition behavior still remarkable, shows giant magnetio-caloric effects, increase Curie temperature to high-temperature mobile with C content.

embodiment 2: preparation La _0.7 ce _0.3 (Fe _1-x co _x ) _11.6 si _1.4 (x=0.04,0.06,0.08) three kinds of magnetic materials

The present embodiment provides prepares La by chemical formula _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4the instantiation of (x=0.04,0.06,0.08) magnetic material, preparation technology is:

1) by La _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4(x=0.04,0.06,0.08) chemical formula is prepared burden, and raw material is impure LaCe alloy and Fe, Co, Si, La, and wherein, simple substance La is used for the part of La deficiency in supplementary LaCe alloy;

2) by the raw material mixing in step 1), put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 2 times with the high-purity argon gas that purity is 99.996wt%, being filled with purity afterwards in furnace chamber is 99.996wt% high-purity argon gas to atmospheric pressure, Arc, obtain alloy pig, each alloy spindle melt back 4 times, smelting temperature is 2000 DEG C, after melting terminates, in copper crucible, cooling obtains cast alloy ingot;

3) by step 2) in the cast alloy ingot for preparing wrap with molybdenum foil respectively, be sealed in high vacuum (1 × 10 ^-4pa) in quartz ampoule, anneal 30 days at 1080 DEG C, break quartz ampoule Quenching in liquid nitrogen, obtain and there is NaZn ₁₃the La of type structure _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4(x=0.04,0.06,0.08) sample.

performance test:

One, utilize Cu target X-ray diffractometer to determine room temperature X-ray diffraction (XRD) collection of illustrative plates of sample, as shown in Figure 5, result shows La _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4(x=0.04,0.06,0.08) three sample principal phases are NaZn ₁₃type structure, α-Fe the dephasign the most easily occurred in this kind of system does not all occur in these three samples, whether a small amount of unknown dephasign (marking * peak in Fig. 5) occurred need further confirmation with the existence of impurity is relevant in raw material LaCe alloy, these a small amount of unknown dephasign and NaZn ₁₃type principal phase coexists, but the existence of dephasign does not affect NaZn ₁₃the generation of type principal phase and growing up.

Two, at superconductive quantum interference vibrating specimen magnetometer MPMS(SQUID) VSM measures La _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4(x=0.04,0.06,0.08) sample pyromagnetic (M-T) curve under 0.02T magnetic field, as shown in Figure 6.Can find out, temperature lag is very little, is increased to x=0.08 Curie temperature T with Co content from x=0.04 _c280K is risen to from 222K.

At MPMS(SQUID) VSM determines La _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4rise the magnetization curve (MH curve) of field process under (x=0.04,0.06,0.08) sample different temperatures, be shown in Fig. 7 a-c.On MH curve, the appearance of flex point (or Arrott schemes (Fig. 7 d) flex point or negative slope) shows that induced by magnetic field becomes the existence of magnetic transition behavior from paramagnetic to ferrimagnetic state, show that the existence of impurity in LaCe alloy raw material does not affect the generation of 1:13 phase, do not affect the appearance becoming magnetic transition behavior simultaneously, ensure that the large magneto-caloric effect of material yet.Meanwhile, along with the increase of Co content, become magnetic transition behavior and weaken, flex point disappears.

According to Maxwell relation: $\mathrm{\&Delta;S}(T,H)=S(T,H)-S(T,0)={\&Integral;}_0^H{\left(\frac{\&PartialD;M}{\&PartialD;T}\right)}_H\mathrm{dH},$ Δ S can be become from isothermal magnetization curve calculation magnetic entropy.Fig. 8 illustrates La _0.7ce _0.3(Fe _1-xco _x) _11.6si _1.4(x=0.04,0.06,0.08) under different magnetic field Δ S to the dependence of temperature.Can find out, Δ S peak shape, along with the increase in magnetic field is to high-temperature region asymptotic expansion, derives from the change magnetic transition behavior from paramagnetic to ferrimagnetic state of the above induced by magnetic field of Curie temperature, demonstrates the existence of the change magnetic transition behavior of system.Along with the increase of Co content, become magnetic transition behavior and weaken, Δ S peak shape progressively tends to symmetrical.With the asymmetric broadening in magnetic field, Δ S peak shape shows that the existence of impurity in LaCe alloy raw material does not affect the generation of 1:13 phase further, also do not affect the appearance becoming magnetic transition behavior, ensure that the large magneto-caloric effect of material.X=0.04,0.06,0.08 three sample, under 0-5T changes of magnetic field, Δ S peak value is respectively 25.1J/kgK, 18.2J/kgK, 14.1J/kgK, be positioned at 222K, 255K, 277K, the magnetic entropy all higher than conventional chamber temperature magnetic refrigerating material Gd becomes (under 5T magnetic field, magnetic entropy becomes 9.8J/kgK), halfwidth is 20.6K, 23.8K, 30.8K respectively, and refrigerating capacity is 448.8J/kg, 350.8J/kg, 340.3J/kg respectively.

Conclusion: the present embodiment can confirm with technical pure LaCe alloy for raw material, by described preparation technology, can prepare and have NaZn ₁₃the La (Fe, Si) of type crystal structure ₁₃based compound, Co substitutes Fe can make Curie temperature rise near room temperature.In LaCe alloy raw material, the existence of impurity does not affect NaZn ₁₃the formation of phase and growing up, diagram of system reveals giant magnetio-caloric effects.

embodiment 3: preparation La _0.95-y ce _0.05 pr _y fe _11.5 si _1.5 (y=0.1,0.5) two kinds of magnetic materials

The present embodiment provides prepares La by chemical formula _0.95-yce _0.05pr _yfe _11.5si _1.5the instantiation of (y=0.1,0.5) magnetic material, preparation technology is:

1) by La _0.95-yce _0.05pr _yfe _11.5si _1.5(y=0.1,0.5) chemical formula is prepared burden, and raw material is impure LaCe alloy (purity 95.91at.%) and Fe, Co, Si, La, Pr, and wherein, simple substance La is used for the part of La deficiency in supplementary LaCe alloy;

2) by the raw material mixing in step 1), put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 2 times with the high-purity argon gas that purity is 99.996wt%, being filled with purity afterwards in furnace chamber is 99.996wt% high-purity argon gas to atmospheric pressure, Arc, obtain alloy pig, each alloy spindle melt back 6 times, smelting temperature is followed successively by 1800 DEG C, 1900 DEG C, 2000 DEG C, 2100 DEG C, 2300 DEG C, 2500 DEG C, after melting terminates, in copper crucible, cooling obtains cast alloy ingot;

3) by step 2) in the cast alloy ingot for preparing wrap with molybdenum foil respectively, be sealed in high vacuum (9 × 10 ^-4pa) in quartz ampoule, anneal 50 days at 1100 DEG C, break quartz ampoule Quenching in liquid nitrogen, obtain and there is NaZn ₁₃the La of type structure _0.95-yce _0.05pr _yfe _11.5si _1.5(y=0.1,0.5) sample.

performance test:

One, utilize Cu target X-ray diffractometer to determine room temperature X-ray diffraction (XRD) collection of illustrative plates of sample, as shown in Figure 9, result shows La _0.95-yce _0.05pr _yfe _11.5si _1.5(y=0.1,0.5) sample crystallization is NaZn ₁₃type structure, a small amount of dephasign observed is in fig .9 with No. * mark.

Two, superconductive quantum interference vibrating specimen magnetometer MPMS(SQUID is utilized) VSM measurement obtains La _0.95-yce _0.05pr _yfe _11.5si _1.5the magnetic of (y=0.1,0.5) two kinds of samples.Pyromagnetic (M-T) curve that Figure 10 measures under giving 0.02T magnetic field, can find out, Pr content increases to y=0.5 from y=0.1, Curie temperature T _c177K is dropped to from 187K.Temperature lag increases to about 5K by about 3K, shows that first order phase change character strengthens.According to Maxwell relation: Δ S can be become from isothermal magnetization curve calculation magnetic entropy.Figure 11 illustrates La _0.95-yce _0.05pr _yfe _11.5si _1.5(y=0.1,0.5) two kinds of samples magnetic entropy under 0 ~ 5T changes of magnetic field becomes Δ S to the dependence of temperature.Under 0-5T changes of magnetic field, effective magnetic entropy becomes (platform) and is respectively 22.7J/kgK(y=0.1), 26.0J/kgK(y=0.5), increase effective magnetic entropy time-varying amplitude with Pr content and strengthen.

Conclusion: the present embodiment can confirm with technical pure LaCe alloy for raw material, by described preparation technology, can prepare and have NaZn ₁₃the La (Fe, Si) of type crystal structure ₁₃based compound, in LaCe alloy raw material, the existence of impurity does not affect NaZn ₁₃the formation of phase and growing up, along with Rare-Earth Ce, Pr substitute La, Curie temperature moves to low temperature, and first order phase change character strengthens, and effective magnetic entropy time-varying amplitude increases.

embodiment 4: preparation La _0.8 ce _0.2 fe _11.4 si _1.6 b _α (α=0,0.2 and 0.4) three kinds of magnetic materials

1) La is pressed respectively _0.8ce _0.2fe _11.4si _1.6b _α(α=0,0.2 and 0.4) chemical formula is prepared burden, and raw material is La, technical pure LaCe alloy (purity 95.91at.%) and Fe, Si and FeB, and simple substance La is used for the part of supplementing La deficiency in LaCe alloy.FeB alloy is used to provide B, owing to also containing Fe element in FeB alloy, needs suitably to reduce the simple substance Fe added, makes the proportioning of the various elements of interpolation still meet the atom ratio of magnetic material chemical formula.

2) raw material of step 1) is mixed, put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 2 times with the high-purity argon gas that purity is 99.996wt%, being filled with purity afterwards in furnace chamber is 99.996wt% high-purity argon gas to one 1.5 atmospheric pressure, Arc (after Arc, raw material are just molten becomes alloy together), obtain alloy pig, each alloy spindle melt back 6 times, 3 times smelting temperature is 1800 DEG C, rear 3 smelting temperatures are 2000 DEG C, after melting terminates, in copper crucible, cooling obtains cast alloy ingot.

3) by step 2) the cast alloy ingot for preparing wraps with molybdenum foil respectively, is sealed in high vacuum (1 × 10 ^-4pa), in quartz ampoule, anneal 60 days at 1030 DEG C, break quartz ampoule ice quenching-in water, obtain three kinds of La _0.8ce _0.2fe _11.4si _1.6b _αalloy (α is respectively 0,0.2 and 0.4).

performance test:

One, the La that Cu target X-ray diffractometer determination step (4) is obtained is utilized _0.8ce _0.2fe _11.4si _1.6b _αroom temperature X-ray diffraction (XRD) collection of illustrative plates (Figure 12) of (α=0,0.2 and 0.4) alloy, discovery alloy crystallization is NaZn ₁₃type structure, may detect the dephasigns such as a small amount of α-Fe, marks with No. *.

Two, at MPMS(SQUID) magnetic of the obtained alloy of the upper determination step of VSM (3).Figure 13 illustrates sample pyromagnetic (M-T) curve under 0.02T magnetic field that step (3) obtains, and can find out La _0.8ce _0.2fe _11.4si _1.6b _αphase transition temperature is respectively 183K(α=0), 187K(α=0.2), 195K(α=0.4).Become according to magnetic entropy under the 0-1T changes of magnetic field of Maxwell relation calculation sample and be respectively 24.8J/kgK(α=0), 23.9J/kgK(α=0.2), 11.6J/kgK(α=0.4) (Figure 14).

Conclusion: the present embodiment can confirm with technical pure LaCe alloy for raw material, by described preparation technology, can prepare and have NaZn ₁₃the La (Fe, Si) of type crystal structure ₁₃base boride, in LaCe alloy raw material, the existence of impurity does not affect NaZn ₁₃the formation of phase and growing up, diagram of system reveals giant magnetio-caloric effects, increases Curie temperature to high-temperature mobile with B content.

embodiment 5: preparation La _0.9 ce _0.1 (Fe _0.6 co _0.2 mn _0.2 ) _13-y si _y (y=0.9,1.8) two kinds of magnetic materials

1) by La _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _y(y=0.9,1.8) chemical formula is prepared burden, and raw material is technical pure LaCe alloy (purity 95.91at.%) and Fe, Si, Co, Mn, La, and wherein, simple substance La is used for the part of La deficiency in supplementary LaCe alloy.

2) raw material of step 1) is mixed, put into arc furnace, be evacuated to 2 × 10 ^-3pa, with the argon purge furnace chamber 2 times that purity is 99.6%, being filled with purity afterwards in furnace chamber is 99.6% argon gas to 0.6 atmospheric pressure, Arc (after Arc, raw material are just molten becomes alloy together), obtain alloy pig, each alloy spindle melt back 5 times, smelting temperature is 2400 DEG C, after melting terminates, in crucible, cooling obtains cast alloy ingot.

3) by step 2) in the cast alloy ingot for preparing wrap with molybdenum foil respectively, be sealed in quartz ampoule, back end vacuum: 1 × 10 ^-4pa, (object is to reach quartzy softening temperature back balance external pressure in temperature to 0.2 atmospheric pressure to fill high-purity argon gas (99.996wt%) under room temperature, quartz ampoule is indeformable), anneal 3 days at 1300 DEG C afterwards, stove is as cold as 1100 DEG C, take out from stove and break quartz ampoule Quenching in liquid nitrogen, obtain and there is NaZn ₁₃the La of type structure _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _ythe alloy of (y=0.9,1.8) two kinds of components.

performance test:

One, the La that Cu target X-ray diffractometer determination step (4) obtains is utilized _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _yroom temperature X-ray diffraction (XRD) collection of illustrative plates (Figure 15) of (y=0.9 and 1.8) alloy, result shows, principal phase structure is NaZn ₁₃, there is a small amount of α-Fe and unknown dephasign (indicating dephasign with *) in type structure.

Two, MPMS(SQUID is utilized) La that obtains of VSM determination step (4) _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _ythe magnetic of (y=0.9 and 1.8) alloy.Figure 16 gives La _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi _y(y=0.9 and 1.8) alloy pyromagnetic (M-T) curve under 0.02T magnetic field.Can find out, La _0.9ce _0.1(Fe _0.6co _0.2mn _0.2) _13-ysi(y=0.9 and 1.8) phase transition temperature lay respectively at 97K and 70K.According to Maxwell relation, calculating Entropy Changes under 0-5T changes of magnetic field is 1.6J/kgK and 2.5J/kgK respectively.

Conclusion: can confirm with technical pure LaCe alloy as raw material in conjunction with previous embodiment and the present embodiment, by described preparation technology, all can prepare in larger compositional range (Co content 0≤p≤0.2, Mn content 0≤q≤0.2, Si content 0.8≤y≤2) and there is NaZn ₁₃the La (Fe, Si) of type crystal structure ₁₃base magneto-caloric effect material.

embodiment 6: preparation La _0.7 ce _0.3 fe _11.5 si _1.5 c _0.2 h _0.45 and La _0.7 ce _0.3 fe _11.5 si _1.5 c _0.2 b _0.05 h _0.55 two kinds of magnetic materials

1) by La _0.7ce _0.3fe _11.5si _1.5c _0.2and La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05chemical formula is prepared burden, and raw material is technical pure LaCe alloy (purity 95.91at.%) and FeC, FeB, Si, La, and wherein, simple substance La is used for the part of La deficiency in supplementary mishmetal.

2) raw material of step 1) is mixed, put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 1 time with the high-purity argon gas that purity is 99.996wt%, being filled with purity afterwards in furnace chamber is 99.996wt% high-purity argon gas to atmospheric pressure, Arc (after Arc, raw material are just molten becomes alloy together), obtain alloy pig, each alloy spindle melt back 2 times, smelting temperature is 2000 DEG C, after melting terminates, in copper crucible, cooling obtains cast alloy ingot.

3) by step 2) the cast alloy ingot for preparing wraps with molybdenum foil respectively, is sealed in high vacuum (1 × 10 ^-4pa) in quartz ampoule, anneal 30 days at 1080 DEG C, break quartz ampoule Quenching in liquid nitrogen, obtain La _0.7ce _0.3fe _11.5si _1.5c _0.2and La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05two kinds of alloys.

4) La will prepared in step 3) _0.7ce _0.3fe _11.5si _1.5c _0.2and La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05two kinds of alloys are divided into alloying pellet, particle size range: 0.05 ~ 2mm.

5) alloying pellet utilizing P-C-T tester step 4) to be obtained does annealing in process in hydrogen:

1, first, for La _0.7ce _0.3fe _11.5si _1.5c _0.2sample, the La that step 4) is obtained _0.7ce _0.3fe _11.5si _1.5c _0.2alloying pellet puts into the high pressure sample chamber of P-C-T tester, is evacuated to 1 × 10 ^-1pa, rises to 350 DEG C by sample cavity temperature, backward sample cavity in pass into high-purity H ₂(purity: 99.99%), by H ₂pressure is adjusted to 0.101 respectively, 0.205,0.318,0.411,0.523,0.617,0.824,1.014MPa(1 atmospheric pressure ≈ 0.101325MPa), and keep the suction hydrogen time to be 1 minute under each pressure, afterwards high pressure sample chamber container is put into the water of room temperature (20 DEG C), be cooled to room temperature, analyze and calculating of weighing according to P-C-T, determine that H content is about 0.45, thus obtain La _0.7ce _0.3fe _11.5si _1.5c _0.2h _0.45hydride magnetic refrigerating material.

2, for La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05sample, the La that step 4) is obtained _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05alloying pellet puts into the high pressure sample chamber of P-C-T tester, is evacuated to 1 × 10 ^-1pa, rises to 200 DEG C by sample cavity temperature, backward sample cavity in pass into high-purity H ₂(purity: 99.99%), by H ₂pressure is adjusted to 0.0125 respectively, 0.0543,0.115,0.168,0.218,0.274,0.326,0.419MPa(1 atmospheric pressure ≈ 0.101325MPa), keeping inhaling the hydrogen time under the first seven Hydrogen Vapor Pressure is 1 minute, in the end keep 3 days under a Hydrogen Vapor Pressure, afterwards high pressure sample chamber container is put into the water of room temperature (20 DEG C), be cooled to room temperature, analyze and calculating of weighing according to P-C-T, determine that H content is about 0.55, thus obtain La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05h _0.55hydride magnetic refrigerating material.It should be noted that: hydrogen－sucking amount depends on the temperature and pressure inhaled in hydrogen process, inhaling the adjustable hydrogen－sucking amount of hydrogen temperature and pressure by regulating, stop to obtain different hydrogen－sucking amount under difference inhales hydrogen pressure.

performance test:

One, the La that Cu target X-ray diffractometer determination step (5) is obtained is utilized _0.7ce _0.3fe _11.5si _1.5c _0.2h _0.45and La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05h _0.55room temperature X-ray diffraction (XRD) collection of illustrative plates of two kinds of hydride material, result shows two kinds of hydride material and is NaZn ₁₃type structure.

Two, at MPMS(SQUID) the obtained La of the upper determination step of VSM (5) _0.7ce _0.3fe _11.5si _1.5c _0.2h _0.45and La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05h _0.55the magnetic of two kinds of hydride material.Figure 17 a, b and Figure 18 a, b provide the former respectively and become (Δ S) dependence (calculate and rise field Δ S) to temperature with pyromagnetic (M-T) curve under the latter 0.02T magnetic field and according to the magnetic entropy that Maxwell relation calculates.Find La _0.7ce _0.3fe _11.5si _1.5c _0.2h _0.45and La _0.7ce _0.3fe _11.5si _1.5c _0.2b _0.05h _0.55two kinds of hydride material phase transition temperatures lay respectively at ~ 248K and ~ 259K; Under 0-5T changes of magnetic field, magnetic entropy change (Δ S) maximum is respectively about 19.3J/kgK and 18.1J/kgK, and magneto-caloric effect amplitude is considerable.

Conclusion: the La (Fe, Si) prepared for raw material with technical pure LaCe alloy ₁₃base carbide/carbon-boron compound anneal under a hydrogen atmosphere obtain Multiple level carbon/boron/hydrogen compound present considerable magneto-caloric effect, inhaling hydrogen technique by regulation and control can regulate the phase transition temperature of material to high-temperature mobile, thus making material have great magnetic entropy variation at high temperature, the magnetic refrigeration application for reality is significant.

embodiment 7: preparation La _0.7 ce _0.21 (Pr _0.25 nd _0.75 ) _0.09 fe _11.6 si _1.4 magnetic material

The present embodiment provides prepares La by chemical formula _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4the instantiation of magnetic refrigerating material, preparation technology is:

1) by La _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4chemical formula is prepared burden, and raw material is technical pure LaCe alloy (95.91at.%) and Fe, Si, La, Pr and Nd.Wherein, La is used for the part of La deficiency in supplementary LaCe alloy.

2) by the raw material mixing in step 1), put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 2 times with the high-purity argon gas that purity is 99.996wt.%, high-purity argon gas to one atmospheric pressure that purity is 99.996wt.% is filled with afterwards in furnace chamber, Arc (after Arc, raw material are just molten becomes alloy together), obtain alloy pig, each alloy spindle melt back 4 times, smelting temperature is 2000 DEG C, and melting terminates rear cooling and obtains cast alloy ingot;

3) by step 2) in the cast alloy ingot for preparing wrap with molybdenum foil respectively, be sealed in high vacuum (1 × 10 ^-4pa) in quartz ampoule, anneal 30 days at 1080 DEG C, break quartz ampoule Quenching in liquid nitrogen, obtain and there is NaZn ₁₃the La of type structure _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4sample.

performance test:

One, utilize Cu target X-ray diffractometer to determine room temperature X-ray diffraction (XRD) collection of illustrative plates of sample, as shown in figure 19, result shows La _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4sample principal phase is NaZn ₁₃, there is a small amount of unknown dephasign (with No. * mark in Figure 19) in type structure.

Two, at superconductive quantum interference vibrating specimen magnetometer MPMS(SQUID) VSM measures La _0.7ce _0.21(Pr _0.25nd _0.75) _0.09fe _11.6si _1.4sample pyromagnetic (M-T) curve under 0.02T magnetic field, as shown in figure 20, can find out, the Curie temperature T of sample _cbe positioned at 170K, temperature lag Δ T is about 8K.Rise the magnetization curve (MH curve) of field process under measuring different temperatures, be shown in Figure 21 according to the magnetic entropy change Δ S that Maxwell relation calculates.We find, under 0-5T changes of magnetic field, the effective magnetic entropy of sample becomes (Δ S platform) is 29.8J/kgK, and halfwidth is 14.8K.The magnetic entropy of the Gao Erkuan platform that flattens is that Ericsson type magnetic refrigerator device needs especially, and the magnetic refrigeration application for reality is significant.

Conclusion: the present embodiment can confirm with technical pure LaCe alloy for raw material, by described preparation technology, can prepare and have NaZn ₁₃the La (Fe, Si) of type crystal structure ₁₃base carbide, in LaCe alloy raw material, the existence of impurity does not affect NaZn ₁₃the formation of phase and growing up, Ce, Pr, Nd introduce alternative La simultaneously can make delayed increase, shows that first order phase change character strengthens, and effective magnetic entropy time-varying amplitude also strengthens thereupon.

embodiment 8: preparation La _0.7 ce _0.3 fe _11.6 si _1.4 c _0.1 h _2.9 magnetic material

The present embodiment provides prepares La by chemical formula _0.7ce _0.3fe _11.6si _1.4c _0.1the instantiation of magneto-caloric effect material, preparation technology is:

1) by La _0.7ce _0.3fe _11.6si _1.4c _0.1chemical formula is prepared burden, and raw material is technical pure LaCe alloy (95.91at.%) and La, FeC, Fe, Si, and simple substance La can be used to the part of La deficiency in supplementary mishmetal.

2) raw material of step 1) is mixed, put into arc furnace, be evacuated to 2 × 10 ^-3pa, furnace chamber is cleaned 2 times with the high-purity argon gas that purity is 99.996wt%, high-purity argon gas to 1.4 atmospheric pressure that purity is 99.996wt% is filled with afterwards in furnace chamber, Arc (after Arc, raw material are just molten becomes alloy together), obtain alloy pig, each alloy spindle melt back 2 times, smelting temperature is 2000 DEG C, after melting terminates, in copper crucible, cooling obtains cast alloy ingot.

3) by step 2) the cast alloy ingot for preparing wraps with molybdenum foil respectively, is sealed in high vacuum (1 × 10 ^-4pa) in quartz ampoule, anneal 10 days at 1100 DEG C, break quartz ampoule Quenching in liquid nitrogen, obtain La _0.7ce _0.3fe _11.6si _1.4c _0.1alloy material.

4) La will prepared in step 3) _0.7ce _0.3fe _11.6si _1.4c _0.1irregular particle is made in alloy material fragmentation, average particle size range: 20 ~ 200 microns.

5) La that P-C-T tester obtains step 4) is utilized _0.7ce _0.3fe _11.6si _1.4c _0.1alloying pellet does annealing in process in hydrogen: by La _0.7ce _0.3fe _11.6si _1.4c _0.1irregular alloying pellet puts into the high pressure sample chamber of P-C-T tester, is evacuated to 1 × 10 ^-1pa, rises to 120 DEG C by sample cavity temperature, backward sample cavity in pass into high-purity H ₂(purity: 99.99%), by H ₂pressure is adjusted to 1 × 10 respectively ^-5, 2 × 10 ^-3, 0.1015,1.579,2.083,3.054,4.128,5.142,6.190,7.083,8.120,9.653MPa(1 atmospheric pressure ≈ 0.101325MPa), keeping inhaling the hydrogen time under front 11 Hydrogen Vapor Pressures is 25 minutes, in the end keeping under a Hydrogen Vapor Pressure inhaling the hydrogen time is 3 days, afterwards high pressure sample chamber container is put into the water of room temperature (20 DEG C), be cooled to room temperature, analyze and calculating of weighing according to P-C-T, determine that H content is about 2.9; Thus obtain La _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9hydride magnetic refrigerating material.It should be noted that, the hydrogen－sucking amount of described alloy depends on the temperature and pressure inhaled in hydrogen process, inhaling the adjustable hydrogen－sucking amount of hydrogen temperature and pressure, stopping to obtain different hydrogen－sucking amount under difference inhales hydrogen pressure by regulating.

performance test:

One, Cu target X-ray diffractometer is utilized to measure La _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9room temperature X-ray diffraction (XRD) collection of illustrative plates of hydride, principal phase is NaZn ₁₃, there is a small amount of dephasign in type structure.As shown in figure 22, dephasign marks with *.

Two, at MPMS(SQUID) the obtained La of the upper determination step of VSM (5) _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9the magnetic of hydride material, Figure 23 and Figure 24 is pyromagnetic (M-T) curve under 0.02T magnetic field respectively and becomes (Δ S) dependence (calculate and rise field Δ S) to temperature according to the magnetic entropy that Maxwell relation calculates.We find La _0.7ce _0.3fe _11.6si _1.4c _0.1h _2.9the phase transition temperature of hydride material is positioned at ~ 348K, 0-5T changes of magnetic field under magnetic entropy to become maximum be 22.8J/kgK, magneto-caloric effect amplitude is considerable.

Conclusion: the La (Fe, Si) prepared for raw material with technical pure LaCe alloy ₁₃base carbide anneal under a hydrogen atmosphere obtain Multiple level carbon/hydrogen compound present considerable magneto-caloric effect, inhale hydrogen technique by regulation and control and can regulate hydrogen－sucking amount, phase transition temperature to high-temperature mobile, thus makes material have great magnetic entropy variation at high temperature, and the magnetic refrigeration application for reality is significant.

comparative example: rare metal Gd

The room temperature magnetic refrigerating material rare metal Gd (purity: 99.9wt%) of we selected typical is as comparative example.At MPMS(SQUID) VSM records its Curie temperature is 293K, under 0-5T changes of magnetic field, becomes 9.8J/kgK at the magnetic entropy at Curie temperature place.Easy discovery, with most La (Fe, Si) that impure technical pure LaCe alloy is prepared for raw material in above embodiment ₁₃the magnetic entropy of base magnetic refrigerating material becomes all significantly more than Gd, illustrates that this material has larger magneto-caloric effect.

Below describe in detail the present invention with reference to embodiment, to those skilled in the art, should be understood that, above-mentioned embodiment should not be understood to limit scope of the present invention.Therefore, various changes and improvements can made to embodiment of the present invention without departing from the spirit and scope of the present invention.

Claims (11)

1. the La (Fe, Si) for preparing of a rare earth purification intermediate product ₁₃base magnetic refrigerating material, is characterized in that:

Described magnetic refrigerating material has NaZn ₁₃type structure, its chemical general formula is La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _α, wherein,

R is selected from the one or more combination in Pr and Nd element,

A is selected from the one or more combination in C, H and B element,

The scope of x is: 0<x≤0.5,

The scope of y is: 0≤y≤0.5, and x+y<1,

The scope of p is: 0≤p≤0.2,

The scope of q is: 0≤q≤0.2,

The scope of z is: 0.8<z≤1.8,

The scope of α is: 0≤α≤3.0;

Described rare earth purification intermediate product is the impure LaCe alloy with natural proportion extracted from light rare earth ore deposit in rare earth purification process, the purity of described LaCe alloy is 95-98at.%, in alloy, La:Ce atomic ratio is 1:1.6-1:2.3, dopant species in LaCe alloy comprises Pr, Nd, Fe, Si, Cu, Ni, Zn, Th, Y, Mg, Ca, C, H and O, also containing Cu, Ni, Zn, Th, Y, Mg, Ca and the O as impurity in described magnetic refrigerating material.

2. magnetic refrigerating material according to claim 1, wherein, the scope of described α is: 0≤α≤0.8, and the scope of x is: 0<x≤0.3.

3. prepare a method for magnetic refrigerating material described in claim 1 or 2, it is characterized in that, described method comprises the steps:

1) by La _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αthe chemical formula preparation raw material in addition to hydrogen of magnetic refrigerating material, La and Ce element in raw material is provided by the impure LaCe alloy with natural proportion extracted from light rare earth ore deposit in rare earth purification process, and in LaCe alloy, La element insufficient section is supplemented by simple substance La;

2) by step 1) in the raw material for preparing put into arc furnace, vacuumize, with argon purge, and melting under argon shield, obtain alloy pig;

3) by step 2) melted alloy pig vacuum annealing, then at liquid nitrogen or quenching-in water, obtained have NaZn ₁₃the La of structure _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αmagnetic refrigerating material;

Wherein, when the A in chemical formula comprises protium, described method also comprises step 4): by step 3) obtained material is divided into powder, at hydrogen annealing,

Wherein, the purity of described LaCe alloy is 95-98at.%, in alloy, La:Ce atomic ratio is 1:1.6-1:2.3, dopant species in LaCe alloy comprises Pr, Nd, Fe, Si, Cu, Ni, Zn, Th, Y, Mg, Ca, C, H and O, also containing Cu, Ni, Zn, Th, Y, Mg, Ca and the O as impurity in described magnetic refrigerating material.

4. preparation method according to claim 3, it is characterized in that, in described raw material, when A comprises C element, provide C element by FeC alloy, now owing to also containing Fe element in FeC alloy, need suitably to reduce the simple substance Fe added, make the proportioning of the various elements added still meet the atom ratio of magnetic refrigerating material chemical formula, wherein, when A comprises B element, provide B element by FeB alloy.

5. preparation method according to claim 3, is characterized in that, described step 2) comprising: by step 1) in the raw material for preparing put into arc furnace, be evacuated to vacuum degree and be less than 1 × 10 ^-2pa, is greater than argon purge furnace chamber 1-2 time of 99wt%, is filled with this argon gas afterwards to 0.5-1.5 atmospheric pressure, Arc in furnace chamber by purity, obtain alloy pig, melt back 1-6 time at 1500-2500 DEG C of each alloy pig.

6. preparation method according to claim 5, wherein, smelting temperature is 1800-2500 DEG C.

7. preparation method according to claim 3, is characterized in that, described step 3) comprising: by step 2) melted alloy pig 1000-1300 DEG C, vacuum degree is less than 1 × 10 ^-3anneal under the condition of Pa 3-60 days, and then at liquid nitrogen or quenching-in water, thus to prepare principal phase be NaZn ₁₃the La of structure _1-x-yce _xr _y(Fe _1-p-qco _pmn _q) _13-zsi _za _αmagnetic refrigerating material.

8. preparation method according to claim 3, it is characterized in that, described step 4) comprising: by step 3) obtained material segmentation makes the irregular powder that particle diameter is less than 2mm, put into that purity is greater than 99wt%, pressure was 0-100 atmospheric hydrogen, 0-600 DEG C of annealing 1min to 10 day.

9. preparation method according to claim 8, wherein, the pressure of hydrogen is 10 ^-4-100 atmospheric pressure, and 100-350 DEG C of annealing 1 minute to 3 days.

10. a magnetic refrigeration machine, the magnetic refrigerating material that described refrigeration machine comprises the magnetic refrigerating material described in claim 1 or 2 or obtains according to method according to any one of claim 3 to 9.

Magnetic refrigerating material described in 11. claims 1 or 2 or the application of magnetic refrigerating material in manufacture refrigerating material obtained according to method according to any one of claim 3 to 9.