CN101578246A

CN101578246A - Process for manufacturing an LTM perovskite product

Info

Publication number: CN101578246A
Application number: CNA2007800438531A
Authority: CN
Inventors: S·马兰; C·莱维
Original assignee: Saint Gobain Centre de Recherche et dEtudes Europeen SAS
Current assignee: Saint Gobain Centre de Recherche et dEtudes Europeen SAS
Priority date: 2006-10-24
Filing date: 2007-10-24
Publication date: 2009-11-11
Anticipated expiration: 2027-10-24
Also published as: CN101578246B; FR2907471B1; FR2907471A1

Abstract

The present invention relates to a fused product comprising an LTM perovskite, L denoting lanthane, T denoting an element chosen from strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium and mixtures of these elements, and M denoting manganese.

Description

The method for preparing the LTM perovskite product

Technical field

The present invention relates to prepare the novel method of lanthanum-strontium-manganese (LSM) uhligite.

Background technology

The term uhligite is used in reference to routinely for having ABO ₃Any material of type structure.

Lanthanum-strontium-manganese (LSM) uhligite is that wherein A is the lanthanum of doping strontium and the compound that B is manganese.Its structure is following type:

(La _(1-x)Sr _x) _(1-y)MnO ₃

Obtainable in the market lanthanum-strontium-manganese uhligite powder is used in particular for the preparation of Solid Oxide Fuel Cell (SOFC) negative electrode.Usually, they prepare by the following method:

Sol-gel/co-precipitation;

For example described by U.S. Patent No. 5 453 330, synthetic by the solid sintering; With

Synthetic and the pyrolysis by precursor.

Document " Nanomaterials:new elaboration processes using solarfurnaces ", Materials Science Forum, 269-272 rolls up (1998), and the 297-302 page or leaf has also been described the evaporation-condensation method.

Rober t J.Bell, the article of Graeme J.Millar and John Drennan " Influence of synthetis route on the catalytic properties ofLa _1-xSr _xMnO ₃", Solid State Ionics 131 (2000), 211-220 have also described the method for 6 kinds of synthetic lanthanum-strontium-manganese uhligite powder.

The all powder that uses aforesaid method to obtain has the average particle size particle size of quite little (submicron) to medium (about 5 microns μ m).These powder are expensive.

The method that is used to prepare monocrystalline lanthanum-strontium-manganese uhligite also is known, for example referring to EP 0,732 430.Yet these methods also are expensive.

Article " Effect of spray parameters on the electricalconductivity of plasma-sprayed La _1-xSr _xMnO ₃Coating for thecathode of SOFCs " coating that obtains by plasma spraying described.Described in the 279th page, such coating has the laminate structure that casting product does not have.

Therefore have the needs to novel method, this method can be prepared lanthanum-strontium-manganese uhligite with the cost of reduction and with commercial quantities.

The objective of the invention is to address that need.

Summary of the invention

According to the present invention, realized this purpose by the method for preparing lanthanum-strontium-manganese uhligite, this method comprises following step:

A) raw material is mixed to form initial charge;

B) this initial charge is melted to obtain melt liquid; With

C) this melt liquid is solidified to form solid material;

Select described raw material, make the solid material (" being called fused material ") that obtains in the step c) have following chemical constitution by weight percentage, altogether 100%:

36%＜with La ₂O ₃The lanthanum of form meter＜70.7%;

0%＜in strontium＜25.8% of SrO form;

29.3%＜in manganese＜41.2% of MnO form; With

Impurity＜0.7%.

This material can be block or particle form.

In the first embodiment, this method thereby provide preparation to comprise the particulate method of lanthanum-strontium-manganese uhligite, this method comprises following step:

a ₁) raw material is mixed to form initial charge;

b ₁) this initial charge is melted to obtain melt liquid;

c ₁) this melt liquid is disperseed with the drop form; With

d ₁) make described droplet solidification by contacting with oxygen-bearing fluid.

According to the present invention, at step a ₁) in, select described raw material, make steps d ₁) in the solid particulate (being called " consolidation particle ") that obtains have following chemical constitution by weight percentage, altogether 100%:

36%＜with La ₂O ₃The lanthanum of form meter＜70.7%;

0%＜in strontium＜25.8% of SrO form;

29.3%＜in manganese＜41.2% of MnO form; With

Impurity＜0.7%.

In second embodiment, the invention provides the method that preparation comprises the block of lanthanum-strontium-manganese uhligite, this method comprises following consecutive steps:

a ₂) raw material is mixed to form initial charge;

b ₂) this initial charge is melted to obtain melt liquid;

c ₂) this melt liquid is cast in the mould;

d ₂) by cooling the liquid of casting is solidified in mould, up to the block that obtains partial coagulation at least; With

e ₂) with the described block demoulding.

According to the present invention, at step a ₂) in, select described raw material, make the block of the demoulding have following chemical constitution by weight percentage, altogether 100%:

36%＜with La ₂O ₃The lanthanum of form meter＜70.7%;

0%＜in strontium＜25.8% of SrO form;

29.3%＜in manganese＜41.2% of MnO form; With

Impurity＜0.7%.

The method steps that the present invention is used to prepare consolidation particle or consolidation block is conventional; and those skilled in the art will know that how to determine raw material so that in described consolidation particle or described consolidation block, obtain described chemical constitution, this is formed and lanthanum-strontium-manganese uhligite (La _1-xSr _x) _1-yMnO ₃Composition identical, wherein 0＜x≤0.5 and-0.05≤y≤0.24.Yet the inventor finds that unexpectedly such conventional steps produces the uhligite phase of high per-cent.

Ordinary method is particularly implemented to jet or is atomized to make the particulate method only by regulating the composition of initial charge; therefore make it possible to prepare particles of different sizes or block by melt liquid; outside the removal of impurity; described particle or block have greater than 50%; be preferably greater than 70%; be preferably greater than 90%, more preferably greater than 99%, also more preferably greater than lanthanum-strontium-manganese uhligite per-cent of 99.9% (this specification sheets hereinafter provided the definition of lanthanum-strontium-manganese uhligite per-cent in the product).Technology prejudice has been run counter in this beat all especially discovery, and this prejudice still causes those skilled in the art only to pay close attention to above-mentioned complexity and expensive method so far.

Preferably, the preparation method of the present invention's first and second embodiments also comprises a kind of and preferred multiple following optional feature:

Determine initial charge, make that the chemical analysis results of the particle of preparation or block is as follows, by weight percentage, altogether 100%:

38.4%＜with La ₂O ₃The lanthanum of form meter＜69.7%;

0%＜in strontium＜25.4% of SrO form;

30.3%＜in manganese＜37.2% of MnO form; With

Impurity＜0.7%.

This is formed and lanthanum-strontium-manganese uhligite (La _1-xSr _x) _1-yMnO ₃Composition identical, 0＜x≤0.5 and 0≤y≤0.1 wherein.

47.9%＜with La ₂O ₃The lanthanum of form meter＜69.7%;

0%＜in strontium＜17% of SrO form;

30.3%＜in manganese＜35.7% of MnO form; With

Impurity＜0.7%.

This is formed and lanthanum-strontium-manganese uhligite (La _1-xSr _x) _1-yMnO ₃Composition identical, 0＜x≤0.35 and 0≤y≤0.1 wherein.

Determine initial charge, so that the particle of preparation or the chemical analysis results of block are as follows, by weight percentage, altogether 100%:

47.9%＜with La ₂O ₃The lanthanum of form meter＜61.6%;

6.7%＜in strontium＜17% of SrO form;

31.5%＜in manganese＜35.7% of MnO form; With

Impurity＜0.7%.

This is formed and lanthanum-strontium-manganese uhligite (La _1-xSr _x) _1-yMnO ₃Composition identical, 0.15＜x≤0.35 and 0≤y≤0.1 wherein.

53.9%＜with La ₂O ₃The lanthanum of form meter＜61.6%;

6.7%＜in strontium＜11.8% of SrO form;

31.5%＜in manganese＜34.7% of MnO form; With

Impurity＜0.7%.

This is formed and lanthanum-strontium-manganese uhligite (La _1-xSr _x) _1-yMnO ₃Composition identical, 0.15＜x≤0.25 and 0≤y≤0.1.

Preferably, " with La ₂O ₃The lanthanum of form meter " weight percent greater than 38.4%, be preferably greater than 47.9%, more preferably greater than 53.9%, and/or less than 69.7%, preferably less than 61.6%.

Preferably, the weight percent of " in the strontium of SrO form " is preferably greater than 6.7% greater than 0.8%, and/or less than 25.4%, preferably less than 17%, is more preferably less than 11.8%.

Preferably, the weight percent of " in the manganese of MnO form " is preferably greater than 31.5% greater than 30.3%, and/or less than 37.2%, preferably less than 35.7%, is more preferably less than 34.7%.

Preferably, the preparation method of first embodiment of the invention also comprises a kind of and preferred multiple following optional feature:

At step b ₁) in, use electric arc furnace;

At step c ₁) in, described melt liquid is contacted, preferably with steps d with oxygen-bearing fluid ₁In employed identical;

Dispersion and coagulation step are simultaneously;

Keep the contact between drop and the oxygen-bearing fluid, solidify fully up to described drop;

Step c ₁) and/or steps d ₁) in oxygen-bearing fluid (being preferably air) comprise at least 20 volume % or even the oxygen of at least 25 volume %; With

In steps d ₁) after, the consolidation particle is annealed.

Preferably, described particle at 1050 ℃-1400 ℃, is annealed under the preferred 1150 ℃ temperature, soaking is at least 30 minutes under this temperature, is preferably greater than 2 hours, is preferably about 5 hours.More preferably, described particle under the atmosphere that comprises at least 20 volume % oxygen, preferably under air, is preferable under the barometric point and anneals.

Preferably, the preparation method of second embodiment of the invention also comprises a kind of and preferred multiple following optional feature:

At step b ₂) in, use induction furnace;

At step c ₂) in and/or in steps d ₂) in and/or at step e ₂) after, making the melt liquid and the oxygen-bearing fluid that are solidifying, preferred oxygen-containing gas is air for example, directly or indirectly contact.Preferably, after with the block demoulding, begin described contact at once.More preferably, keep this contact to solidify fully up to block;

The rate of cooling of solidificating period is opened/second (K/s) less than 1000 all the time, preferably less than 100K/s, is more preferably less than 50K/s;

Before solidifying fully, block carries out step e ₂) the demoulding;

Preferably,, preferably when it has enough rigidity with its shape of basic maintenance, carry out the demoulding, and more preferably, this block is contacted with oxygen-bearing fluid the block demoulding as quickly as possible;

At step e ₂) after, with the block annealing of the demoulding.Preferably with this block at 1050 ℃-1400 ℃, anneal under the preferred 1150 ℃ temperature, under this temperature, carry out soaking, soaking reaches the moment metering on soaking temperature (on the surface of this block and in the core of this block) from whole block, all thermal endurance is preferably greater than 30 minutes, is preferably greater than 2 hours and is preferably about 5 hours.More preferably, described block under the atmosphere that comprises at least 20 volume % oxygen, preferably under air, is preferable under the barometric point and anneals;

Choose wantonly after annealing, for example by pulverizing and/or grinding, the in flakes broken or powder with the block of the demoulding.Preferred application choice particle size on the estimation then.

The present invention also provides the consolidation product of consolidation particle or consolidation block form; outside the removal of impurity; this product has greater than 50%; be preferably greater than 70%; more preferably greater than 90%; also more preferably greater than lanthanum-strontium-manganese uhligite per-cent of 99%, this product has following chemical constitution by weight percentage, and altogether 100%:

36%＜with La ₂O ₃The lanthanum of form meter＜70.7%;

0%＜in strontium＜25.8% of SrO form;

29.3%＜in manganese＜41.2% of MnO form; With

Impurity＜0.7%.

Preferably, outside the removal of impurity, this product has the described formula (La greater than 99.9% _1-xSr _x) _1-yMnO ₃Lanthanum-strontium-manganese uhligite, wherein 0＜x≤0.5 and-0.05≤y≤0.24, parameter x in the formula and y are each atoms of elements ratio.

Preferably, product of the present invention comprises a kind of and preferred more than a kind of following optional feature:

Use the method according to this invention to obtain maybe can obtain product of the present invention.

Product of the present invention has greater than 38.4%, is preferably greater than 47.9%, more preferably greater than 53.9%, and/or less than 69.7%, preferably less than 61.6% " with La ₂O ₃The lanthanum of form meter " weight percent.

Product of the present invention has greater than 0.8%, is preferably greater than 6.7%, and/or less than 25.4%, preferably less than 17%, is more preferably less than the weight percent of 11.8% " in the strontium of SrO form ".

Product of the present invention has greater than 30.3%, is preferably greater than 31.5%, and/or less than 37.2%, preferably less than 35.7%, is more preferably less than the weight percent of 34.7% " in the manganese of MnO form ".

Outside the removal of impurity, product of the present invention has the formula (La greater than 99.9% _1-xSr _x) _1-yMnO ₃Lanthanum-strontium-manganese uhligite, preferred x＞0.02, preferred 0.15＜x, and/or x＜0.35, preferred x＜0.25.

Outside the removal of impurity, product of the present invention has lanthanum-strontium-manganese uhligite and 0≤y and/or y≤0.1 greater than 99.9%.

Advantageously, these back two kinds of preferred characteristics (pr é f é rence) are given the high electric conductivity performance of casting product and are made it be particularly suitable for the negative electrode of (may after grinding) preparation Solid Oxide Fuel Cell (SOFC).

Product of the present invention can have thickness greater than 1 millimeter (mm), is preferably greater than 2mm, is preferably greater than 5 centimetres (cm), and more preferably greater than the bulk shape of 15cm, the described thickness of block is its smallest dimension.This block preferably has the weight greater than 200 grams (g).

Product of the present invention also can show as particle shape, and it can have the optional feature below one or more:

Use the method according to this invention to obtain maybe can obtain particle of the present invention.

Particle of the present invention has greater than 38.4%, is preferably greater than 47.9%, more preferably greater than 53.9%, and/or less than 69.7%, preferably less than 61.6% " with La ₂O ₃The lanthanum of form meter " weight percent.

Particle of the present invention has greater than 0.8%, is preferably greater than 6.7%, and/or less than 25.4%, preferably less than 17%, is more preferably less than the weight percent of 11.8% " in the strontium of SrO form ".

Particle of the present invention has greater than 30.3%, is preferably greater than 31.5%, and/or less than 37.2%, preferably less than 35.7%, is more preferably less than the weight percent of 34.7% " in the manganese of MnO form ".

Outside the removal of impurity, particle of the present invention has the formula (La greater than 99.9% _1-xSr _x) _1-yMnO ₃Lanthanum-strontium-manganese uhligite per-cent, preferred x＞0.02, preferred 0.15＜x, and/or x＜0.35, preferred x＜0.25.

Outside the removal of impurity, particle of the present invention has lanthanum-strontium-manganese uhligite and 0≤y and/or y≤0.1 greater than 99.9%.Advantageously, these back two kinds of preferred characteristics are given the high electric conductivity performance of described particle and are made them be particularly suitable for the negative electrode of (may after grinding) preparation Solid Oxide Fuel Cell (SOFC).

Product of the present invention can also be that size is less than 4mm, for example less than the particle form of 3mm.The particulate sphericity can be preferably greater than 0.6 greater than 0.5, and wherein sphericity is defined as the ratio between its smallest dimension and its out to out.

Product of the present invention does not need the thermal treatment of annealing after it solidifies or cools off, and/or does not need through grinding.

At last; the invention provides particle or block (may after the grinding) application in the preparation of Solid Oxide Fuel Cell (SOFC) negative electrode, described particle or block are by implementing method of the present invention or using particularly consolidation particle and producing of consolidation product of the present invention.

Outside the removal of impurity, the per-cent of lanthanum-strontium-manganese uhligite uses following formula (1) definition:

T＝100×(A _LSM)/(A _LSM+A _{30.4＜2θ＜31.6})(1)

Wherein:

A _LSMBe the bimodal area of master of the lanthanum-strontium-manganese uhligite of the no deconvolution processing that on x-ray diffraction pattern, records, obtain described diffractogram by the D5000 diffractometer type device that is equipped with copper DX pipe from supplier Bruker; With

A _{30.4＜2 θ＜31.6}Be the area of the no deconvolution processing of those phases of recording on identical diffractogram, described have diffraction peak in the angular range that ° extends to 2 θ=31.6 from 2 θ=30.4.Especially, La ₂MnO ₄In this angular range, has diffraction peak.

Generally speaking, term " consolidation product " is meant (may through the annealing) solid phase prod that is obtained by solidifying fully of fluid composition (being called " melt liquid " here).At step e ₂) " demoulding " product that obtains when finishing may still comprise the zone of ot-yet-hardened, and therefore it not taken as be the consolidation product at once after the demoulding.

Term " consolidation particle " is meant by making fluid composition solidify the solid particulate of (may through annealing) of gained.

Term particle " size " is meant the mean value of its out to out dM and its smallest dimension dm: (dM+dm)/2.

The thickness of block is its smallest dimension.

Term " impurity " be meant the inevitable inevitable composition of introducing with raw material or from the reaction of these compositions.

Describe below that the present invention prepares the particulate method in the first embodiment of the invention in detail.

At step a ₁) in, use specific oxide compound or its precursor to form initial charge.Can regulate composition by the mixture that adds pure-oxide or oxide compound and/or precursor, particularly La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO or Mn ₃O ₄

In the present invention, those skilled in the art regulate the composition of initial charge, so that in steps d ₁) obtain particle of the present invention when finishing.Consolidation particulate chemical analysis results of the present invention usually and initial charge basic identical.Yet, when appropriate, those skilled in the art will know that composition how to regulate initial charge, for example for will be between melting period the existence of volatile element or the disappearance of some element take into account.

Preferably, on one's own initiative will be except that La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO and Mn ₃O ₄And the element outside the precursor is incorporated in the initial charge, and other element exists as impurity.

Preferably, La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO and Mn ₃O ₄And the total amount of precursor account for initial charge greater than 99 weight %.

Can in mixing tank, raw material closely be mixed.Then mixture is poured in the smelting furnace.

At step b ₁) in, preferably in electric arc furnace, initial charge is melted.Electric smelting makes it possible to prepare a large amount of particles with favourable efficient.

For example, can use Heroult type electric arc furnace, this electric arc furnace has two electrodes and have an appointment 0.8 meter (m) diameter and can hold about 180 kilograms of (kg) melt liquids of vessel wherein.Voltage is preferably 140 volts of (V)-180V, and power is about 240 kilowatts (kW), and employed energy is 1150 kilowatt-hours/(metric system) ton (kWh/t)-2800kWh/t.

Yet can expect any known smelting furnace, for example the Heroult stove of induction furnace, plasma furnace or other type needs only them and can make the complete fusion of initial charge.And so nonessential, can improve the stirring quality by carrying out bubbling, described in FR 1208577 with oxidizing gas (for example air or oxygen).Particularly can improve the quality that melt liquid is stirred by carrying out bubbling with the gas that comprises 35 volume % oxygen.

At step c ₁) in, the melt liquid materials flow that is preferably 1600 ℃ of-1800 ℃ of temperature is dispersed into small droplets.

Can produce by the materials flow of winding-up melt liquid and disperse.Yet can expect any other method of atomized molten liquid well known by persons skilled in the art.

In steps d ₁) in, by with oxygen-bearing fluid, preferably with gas, more preferably contact and change drop into solid particulate with air and/or steam.Oxygen-bearing fluid preferably includes at least 20 volume %, or even the oxygen of at least 25 volume %.

In a single day preferably this method is modulated, make just at once it to be contacted the drop that forms melt liquid with oxygen-bearing fluid.More preferably, disperse (step c ₁) and solidify (steps d ₁) be basic simultaneously, described melt liquid disperses by the oxygen-bearing fluid that is suitable for cooling off and solidify this liquid.

Preferred the contacting of maintenance and oxygen-bearing fluid particle solidifies fully before at least.

Preferably, do not use except by contact other clotting method cooling off with oxygen-bearing fluid.Therefore, for example preferably do not use drop to face toward the super quenching method that the cool metal wall sprays with melt liquid.

Rate of cooling is the function of particle diameter.For this speed of the particle with 0.3mm size is about 1000K/s.

In steps d ₁) when finishing, obtaining solid particulate of the present invention, described particle has the size of 0.01mm-3mm according to dispersion condition.

Advantageously, and in unexpected and unaccountable mode, melt liquid contacted with oxygen-bearing fluid make it possible under no any annealing steps lanthanum-strontium-manganese uhligite of obtaining commercial quantities with the cost that reduces and significant per-cent, outside the removal of impurity, described per-cent reaches greater than 90% and even greater than 99.9%.

Yet, can there be other phase, for example may be the impurity that produces from raw material.

In preferred embodiments, impurity is except the oxide compound of lanthanum, strontium and manganese and all the components except the combination of such oxide compound.

Especially, can find following surface element: Al as impurity; Ca; Si; Zr; Na; Ba; And Fe.Preferably, in oxide form, content of impurities is less than 0.7 weight %, preferably less than 0.4%, more preferably:

Al ₂O ₃＜0.5%, Al preferably ₂O ₃＜0.1%; And/or

CaO＜0.25%, preferably CaO＜0.05%; And/or

SiO ₂＜0.1%, SiO preferably ₂＜0.06%; And/or

ZrO ₂＜0.5%, ZrO preferably ₂＜0.05%; And/or

Na ₂O＜0.05%; And/or

BaO＜0.1%, preferably BaO＜0.06%; And/or

Fe ₂O ₃＜0.05％。

In steps d ₁) when finishing, obtain particle of the present invention.

At optional later step e ₁) in, particle is introduced in the stove with the thermal treatment of annealing.Advantageously, such annealing is used for further improving the per-cent of lanthanum-strontium-manganese uhligite.Outside the removal of impurity, this makes it possible to obtain to equal substantially lanthanum-strontium-manganese uhligite per-cent of 100%.

Annealing temperature is preferably 1050 ℃-1400 ℃, more preferably 1100 ℃-1200 ℃, is more preferably about 1150 ℃.This temperature preferably kept being longer than 0.5 hour, preferably was longer than 2 hours and was preferably about 5 hours time length.Preferably, under the atmosphere that contains at least 20 volume % oxygen, preferably under air, the environmental stress that is preferable over about 1 crust is implemented described annealing Heating temperature down.

Before or after annealing, can grind consolidation particle of the present invention.In case of necessity, use on the estimation then and carry out the selection of particle size.

Particle of the present invention can advantageously have various size, and the preparation method is not limited to obtain the uhligite powder of sub-micron sized.Therefore it is very suitable for industrial preparation.

In addition, the gained particle can be advantageously used in the negative electrode of preparation Solid Oxide Fuel Cell (SOFC).

Embodiment

Provide following embodiment for illustration purposes, described embodiment does not limit the present invention.Prepare particle tested as follows.

At first, in mixing tank, starting raw material is closely mixed:

La by supplier Treibacher sale ₂O ₃Powder, this powder have greater than the purity of 99 weight % with less than the median size of 45 μ m;

SrCO by supplier SPCH sale ₃Powder, this powder have greater than the purity of 96 weight % and have the underflow that passes through 45 μ m sieve greater than 99%; With

MnO by supplier Delta sale ₂Powder, this powder have the median size greater than the purity of 91 weight % and about 45 μ m.

The initial charge of the 50kg weight that obtains is by this way poured in the Heroult type electrometal furnace.Implement fusing with its fusion (energy that applies changes between 1300kWh/t-2800kWh/t according to embodiment for voltage: 160V, power: 240kW) with long arc then, so that by the whole mixtures of complete and uniform mode fusion.Preparation condition is an oxidisability.

In certain embodiments, described in FR 1208577, improve the stirring quality by carrying out bubbling with the gas that contains 35 volume % oxygen.

In case fusing casts melt liquid so that form materials flow fully.The temperature of the melt liquid that records during the casting is 1600 ℃-1800 ℃.

Be dispersed into the drop of melt liquid with 3 bar pressures winding-up dried compressed air with broken materials flow and with it then.

The air cooling drop of winding-up and they are condensed with consolidation particulate form.Depend on the air blast condition, the consolidation particle can be sphere or other form, can be hollow or solid.They have the size of 0.01mm-3mm usually.

Carry out chemical analysis and to having the per-cent of sample determination lanthanum-strontium-manganese uhligite phase less than 40 μ m median size.

Carry out chemical analysis with x-ray fluorescence.

Use x-ray diffraction pattern to measure the per-cent of lanthanum-strontium-manganese uhligite, described diffractogram is obtained by the D5000 diffractometer that is equipped with copper DX pipe from supplier Bruker.After fusing and solidifying, products obtained therefrom can comprise uhligite mutually and more a spot of other La for example mutually ₂MnO ₄

Use the ICDD card, adopt conventional criterion to determine lanthanum-strontium-manganese uhligite phase by X-ray diffraction.For example ICDD card No.00-053-0058 is applicable to La _0.8Sr _0.2MnO ₃Lanthanum-strontium-manganese uhligite phase.

In fact, when showing below, x-ray diffraction pattern carries out the measurement of lanthanum-strontium-manganese uhligite per-cent:

Main lanthanum-strontium-manganese uhligite phase;

2 θ angles are 30.4 ° of-31.6 ° of less important phases of locating; With

In order to measure other the less important phase that does not have the peak in the angular range that above-mentioned phase considers.

Then, use EVA software (selling) and after deduction continuous background (background 0.8) by supplier Bruker, can be to the phase of all existence (particularly including La ₂MnO ₄) measure the area (no deconvolution processing) between 2 θ=30.4 ° and 31.6 °, and the bimodal area (no deconvolution processing) of the master of lanthanum-strontium-manganese uhligite.Use formula (1) to calculate the per-cent of lanthanum-strontium-manganese uhligite then.

Therefore, if lanthanum-strontium-manganese uhligite is the unique phase that exists in the x-ray diffraction pattern, so A _{30.4＜2 θ＜31.6}Be zero, then uhligite per-cent equals 100%.

Table 1 has gathered the result who obtained before any annealing thermal treatment.

Table 1

Table 1 has shown the validity of the inventive method.

Then below under the condition to embodiment 1 ₁Product heat-treat:

Temperature: 1150 ℃;

Soaking time: 5 hours;

Atmosphere: be in the air under the barometric point (environmental stress).

After thermal treatment, outside the removal of impurity, this product has lanthanum-strontium-manganese uhligite per-cent of 100%.

Describe the method that the present invention who uses second embodiment of the invention prepares the consolidation block below in detail.

At step a ₂) in, by above-mentioned steps a ₁) determine initial charge, for preferred characteristics, particularly relate to the selection that has element or relate to those characteristics that their are measured, with above-mentioned steps a ₁) in identical.

In the present invention, those skilled in the art regulate the composition of initial charge so that at step e ₂) obtain according to block of the present invention when finishing.The chemical analysis results of block of the present invention is identical with initial charge basically usually.Yet, when appropriate, those skilled in the art will know that composition how to modulate initial charge, for example so that the existence of volatile element between melting period or the disappearance of some element are taken into account.

At step b ₂) in, for example in electric arc furnace, with the initial charge fusing, so that whole initial charge are melted in complete and uniform mode.

Electric smelting makes it possible to prepare big block with favourable efficient, and described block may have the thickness of 150mm.For example, can use Heroult type electric arc furnace, this electric arc furnace has two electrodes and has the container that about 0.8m diameter also can hold about 180kg melt liquid.The voltage that uses is preferably 140V-180V, and power is about 240kW, and energy is 1150kWh/t-2800kWh/t.

Yet can expect any known stove, for example the Heroult stove of induction furnace, plasma furnace or other type needs only them and can make the complete fusion of initial charge.And so nonessential, can improve the stirring quality by carrying out bubbling, described in FR 1208577 with oxidizing gas (for example air or oxygen).Can be especially by carrying out the stirring quality that bubbling improves melt liquid by the gas that contains 35 volume % oxygen.

For example press described in the FR 1430962, induction furnace is most preferred.Therefore advantageously, can be before block solidifies fully and the core of block is carried out the demoulding when being still liquid.As in being described below as seen, this early stage demoulding advantageously improves the per-cent of lanthanum-strontium-manganese uhligite.

The temperature of the melt liquid that records during the casting is preferably 1600 ℃-1800 ℃.

At step c ₂) in, melt liquid is cast to is suitable for standing in the mould of melt liquid body lotion.The preferred use by graphite or by castiron mould or as the mould defined in the U.S. Patent No. 3 993119.When adopting induction furnace, think that wire turn constitutes mould.Preferably in air, cast.

In steps d ₂) in, will be poured into liquid cooling in the mould to obtain the block of partial coagulation at least.

At solidificating period, preferably make melt liquid and oxygen-bearing fluid, preferred gas, preferred air contact.In case casting begins promptly to carry out this contact.Yet, preferably after casting, just begin this contact.For actual cause, only after the demoulding, beginning as quickly as possible after the demoulding and preferably with contacting preferably of oxygen-bearing fluid.

Oxygen-bearing fluid preferably comprises at least 20 volume % or even the oxygen of at least 25 volume %.

Preferably, before solidifying fully, block keeps and the contacting of oxygen-bearing fluid.This contact can be directly, for example for the surface that is cast to the melt liquid in the mould, and the interface of formation and ambient air.It can also be indirect, and for example for fused liquid still in the block core, the outside surface of described block solidifies.Must make " wall " that oxygen passes through to constitute in such a way so that arrive melt liquid then.

Preferably, solidifying the beginning back,, be more preferably less than 20 minutes described melt liquids that solidifying that make of beginning and contact with oxygen-bearing fluid preferably less than 30 minutes less than 1 hour.

Advantageously, in unexpected and unaccountable mode, melt liquid is contacted the per-cent that improves lanthanum-strontium in the consolidation block of the present invention-manganese uhligite in remarkable mode with oxygen-bearing fluid, until basic 100%.In order to obtain such per-cent, need not annealing steps afterwards.

In addition, the inventor finds that the rate of cooling of solidificating period is not to improve the deciding factor of lanthanum-strontium-manganese uhligite per-cent.Therefore preferably remaining rate of cooling is lower than 1000K/s, preferably is lower than 100K/s, more preferably less than 50K/s.Advantageously, can therefore use conventional simple method of cooling.Preferably, solidify for making melt liquid, that is, it is condensed, only use contacts with ambient air or carries out the refrigerative mould by the heat transfer fluid circulation especially, perhaps when block being taken out from mould and contain melt liquid, block is contacted with oxygen-bearing fluid.Thereby improve reliability and expense.

At step e ₂) in, with the block demoulding.For helping that melt liquid is contacted with oxygen-bearing fluid, if solidify fully preceding can, then preferably as quickly as possible with the block demoulding.Then at step e ₂) in continue to solidify.

Preferably, in case it is carried out the demoulding when block has the rigidity that can keep its shape substantially.Preferably, with the block demoulding and it is contacted with oxygen-bearing fluid as quickly as possible.

Preferably, carry out the demoulding in less than 20 minutes solidifying beginning back.

After solidifying fully, obtain block of the present invention, this block comprises the amount of the lanthanum-strontium-manganese uhligite of raising, and the raising degree is identical with following situation: at the solidificating period commitment melt liquid is contacted with oxygen and also keep then being in contact with it.

At optional step f ₂) in, the block of the demoulding is put into stove with the thermal treatment of annealing.Advantageously, such annealing makes it possible to significantly improve the per-cent of lanthanum-strontium-manganese uhligite.Therefore can obtain greater than 99%, be preferably greater than 99.9% and even equal lanthanum-strontium-manganese uhligite per-cent (outside the removal of impurity) of 100% substantially.

When lanthanum-strontium-manganese uhligite per-cent (outside removal of impurity) greater than 99.9% the time, the The Nomenclature Composition and Structure of Complexes of lanthanum-strontium-manganese uhligite can be used formula (La _1-xSr _x) _1-yMnO ₃The expression, wherein 0＜x≤0.5 and-0.05≤y≤0.24, parameter x in the formula and y are each atoms of elements ratios.

Advantageously, annealing thermal treatment improves the per-cent of lanthanum-strontium-manganese uhligite, even any melt liquid is contacted with oxygen-bearing fluid, for example because the block of preparation fully solidifies when the demoulding, and in mould, cool off or it is contacted with oxygen-bearing fluid at it.

The annealing heat treatment parameter is the dependent variable of the yardstick of processed block.Preferably, these parameters are as follows:

Annealing temperature: be 1050 ℃-1400 ℃, preferred about 1150 ℃; With

Equal thermal endurance at a certain temperature: greater than 30 minutes, be preferably greater than 2 hours, preferred about 5 hours, reach moment on soaking temperature (on the surface of this block and in the core of this block) from whole block.For example, all less than the block of 5mm, all thermal endurance is preferably about 5 hours for all yardsticks.For the cylindrical block with 200mm diameter and 150mm height, all thermal endurance is preferably about 12 hours.

In all cases, preferably under the atmosphere that comprises at least 20 volume % oxygen, preferably under air, be preferable over the thermal treatment of annealing under about 1 environmental stress that clings to.

Annealing thermal treatment must be carried out after block solidifies fully.Yet before annealing, can be with the broken in blocks or powder of block.Preferably block is ground to form and have about 5mm or less than the particle form of 5mm size.

Method of the present invention produces has the block of the present invention that is mainly lanthanum-strontium-manganese uhligite phase.Especially, after annealing thermal treatment, outside the removal of impurity, annealing block of the present invention or particle have greater than 99%, are preferably greater than 99.9%, are preferably lanthanum-strontium-manganese uhligite per-cent of 100%.

Yet, can there be other phase, for example may be impurity from raw material.Impurity is except the oxide compound of lanthanum, strontium and manganese and all elements except the combination of described oxide compound.

Especially, can find following surface element: Al as impurity; Ca; Si; Zr; Na; Ba; And Fe.Preferably, in the impurity total weight percent of oxide form less than 0.7%, preferably less than 0.4%.More preferably:

Al ₂O ₃＜0.5%, Al preferably ₂O ₃＜0.1%; And/or

CaO＜0.25%, preferably CaO＜0.05%; And/or

SiO ₂＜0.1%, SiO preferably ₂＜0.06%; And/or

ZrO ₂＜0.5%, ZrO preferably ₂＜0.05%; And/or

Na ₂O＜0.05%; And/or

BaO＜0.1%, preferably BaO＜0.06%; And/or

Fe ₂O ₃＜0.05％。

Block of the present invention can advantageously have any yardstick, and the preparation method is not limited to obtain the uhligite powder of sub-micron sized.

Therefore this block is very suitable for industrial preparation.Preferably, this block has greater than 1mm, is preferably greater than 2mm, is preferably greater than 5cm, and more preferably greater than the thickness of 15cm, wherein the thickness of block is its smallest dimension.

In order to obtain for example to be used to prepare the powder of the negative electrode of Solid Oxide Fuel Cell (SOFC), will choose the annealed block subsequently wantonly and pulverize and be ground to required particle size.Advantageously, method of the present invention makes it possible to prepare the particle with various yardsticks, and cost is low.

Preferably, the block of the demoulding is at first pulverized into the sheet of 0-5mm.To the described thermal treatment of annealing, subsequently it is ground to required particle size then.

Provide following embodiment for illustration purposes, described embodiment does not limit the present invention.Block is tested in preparation as follows.

At first, the identical starting raw material of those starting raw materials that will use with the embodiment for first embodiment of the invention closely mixes in mixing tank.

The initial charge that obtains by this way is poured in the electrometal furnace.Use long arc to carry out fusion so that with the whole mixtures of complete and uniform mode fusion.Preparation condition is an oxidisability.The temperature of the melt liquid that records during the casting is 1600 ℃-1800 ℃.

In air, melt liquid is cast in the various moulds then: the mould of making by castiron mould, graphite or as the mould defined in the U.S. Patent No. 3 993 119.

By the rate of cooling in the following formula definition list 2 " Vr ":

Vr＝(Tf-Ts)/t _r

Wherein Tf is meant the temperature (in ℃) of melt liquid during the casting, and Ts is meant that block solidifies temperature constantly (in ℃) fully at it, and t _rBe meant that casting beginning and block solidify the time (in second) between the moment fully.

To grind into powder and representing the sample of the block of casting to carry out chemical analysis and lanthanum-strontium-manganese uhligite mensuration mutually.Described powder has the median diameter less than 40 μ m.

Carry out chemical analysis with x-ray fluorescence.

By above measuring lanthanum-strontium-manganese uhligite per-cent about the described x-ray diffraction pattern of the embodiment that relates to first embodiment.

Table 2 and 2 ' has gathered the result who obtained before any annealing thermal treatment.

Bubbling does not feed gas between melting period.

Embodiment 8 and 9 relates to makes prepared with the following method block: this method is utilized the induction melting according to FR 1430962, and the diameter of wire turn is 275mm, and power is 120kw-220kw, and the frequency that the aperiodicity producer provides is 100kHz-250kHz.

" D999, h888 " is meant the right cylinder of the height h of diameter D with 999mm and 888mm.

Table 2

Embodiment	Voltage (y)	The energy that applies (kWh/t)	The quality (kg) of the charging of fusing	Mould-type	Vr (℃/s)	The yardstick (mm) of casting block
Embodiment	Voltage (y)	The energy that applies (kWh/t)	The quality (kg) of the charging of fusing	Mould-type	Vr (℃/s)	The yardstick (mm) of casting block	1 ₂	140	1200	50	According to US3993119	30	Thickness: the recessed 134mm of 5mm radius
2 ₂	150	2400	46	Graphite	0.055	180×180×150	1 ₂	140	1200	50	According to US3993119	30	Thickness: the recessed 134mm of 5mm radius
2 ₂	150	2400	46	Graphite	0.055	180×180×150	3 ₂	150	1400	46	Graphite	0.055	180×180×150
4 ₂	150	1400	46	Cast iron	0.055	D200，h150	3 ₂	150	1400	46	Graphite	0.055	180×180×150
4 ₂	150	1400	46	Cast iron	0.055	D200，h150	5 ₂	150	1400	46	Cast iron	0.055	D200，h150
6 ₂	180	1400	50	Cast iron	0.055	D200，h150	5 ₂	150	1400	46	Cast iron	0.055	D200，h150
6 ₂	180	1400	50	Cast iron	0.055	D200，h150	7 ₂	180	1400	50	Cast iron	0.055	D200，h150
8 ₂	-	-	75	The wire turn of coil	0.04	D275，h190	7 ₂	180	1400	50	Cast iron	0.055	D200，h150
8 ₂	-	-	75	The wire turn of coil	0.04	D275，h190	9 ₂	-	-	75	The wire turn of coil	0.04	D275，h190

Table 2 '

Table 2 ' shown the validity of the inventive method.Also make it possible to observe, (embodiment 8 between melting period being undertaken by induction ₂With 9 ₂), wherein the surface of demoulding block contacts with airborne oxygen quickly (in these embodiments at the most after 20 minutes, at this moment block does not solidify as yet fully), the per-cent of lanthanum-strontium in the finished product-manganese uhligite is very high, reach basic 100%, therefore advantageously make the thermal treatment of annealing become meaningless.

Subsequently to embodiment 1 ₂, 2 ₂, 4 ₂With 5 ₂The thermal treatment (table 2) of annealing.To the thermal treatment (embodiment 1) of annealing of casting block or the block that is crushed to the 0-5mm scope.Stipulated employed heat treatment parameter in the table 3.In air, heat-treat.

Table 3

Table 3 has shown that this processing causes the obvious raising of lanthanum-strontium-manganese uhligite per-cent, up to basic 100%.

Can be clear that in this point, method of the present invention makes it possible to prepare in simple and cheap mode the product of commercial quantities, particularly particle and block, described product has high lanthanum-strontium-manganese uhligite per-cent and has following chemical analysis results, by weight percentage, altogether 100%:

36%＜with La ₂O ₃The lanthanum of form meter＜70.7%;

0%＜in strontium＜25.8% of SrO form;

29.3%＜in manganese＜41.2% of MnO form; With

Impurity＜0.7%.

This method even make it possible to preparation and have greater than 99.9% or even the formula (La of 100% (outside the removal of impurity) _1-xSr _x) _1-yMnO ₃The product of lanthanum-strontium-manganese uhligite, 0＜x≤0.5 and-0.05≤y≤0.24.

If end-use needs, then can reduce the yardstick of product then, for example with they grind into powder forms.

Certainly, the invention is not restricted to illustrative and non-limiting example and the embodiment of describing and providing.

Except elements strontium, the present invention relates to comprise the product of the product of LTM uhligite, particularly particle or block form, wherein L is meant lanthanum, T is the element that is selected from the mixture of strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium and these elements, and M is meant manganese.The present invention also provides the method for preparing this product.

Think that the embodiment (wherein element T is not limited to strontium) that relates to these products and method is " generalized ".

Common way is with ABO ₃Form is represented the structure of such LTM uhligite.Yet, being entirely accurate, such uhligite has (La _(1-x)T _x) _(1-y)MnO _(3-δ)The structure of type.If have greater than 99.9% LTM uhligite per-cent and the element total amount that constitutes uhligite based on oxide weight per-cent meter greater than 99%, then can and/or determine the value of x and y by chemical analysis by x-ray diffraction pattern as fruit product.Because uhligite is electroneutral, so the δ value is corresponding to guaranteeing that perovskite structure is the required value of electric neutrality.What It is generally accepted is that the δ value depends on the valence state of element manganese substantially.

As described in calling the turn according to the order of sequence, above-mentioned LTM uhligite powder is used in particular for using complexity and expensive methods to prepare the negative electrode of Solid Oxide Fuel Cell.Therefore have the needs to the product that comprises the LTM uhligite, described product can be prepared by the cost and the commercial quantities that reduce.The objective of the invention is to address that need.

More accurately, in present Solid Oxide Fuel Cell (SOFC), be divided into each electrode two-layer usually.In the special case of negative electrode, the first layer serves as current collector layers (CCL).One of raw material that is used as cathode material in the SOFC technology is the powder of adulterated lanthanum-manganese (LTM) uhligite.

Be called " cathode functional " active coating (CFL) in the negative electrode between CCL and ionogen, and must make it possible to supply with electronics so that will be O from the hydrogen reduction of air to system simultaneously ^2-Ion and with these O ^2-Ion is sent in the ionogen.For like this, the mixture by ion conductive material and electronic conductive material (adulterated lanthanum-manganese uhligite) constitutes this activity CFL usually.Must make the optimization that contacts between these two kinds of materials and the air, promptly the number of triple point (pointtriple) must be many as far as possible, and must have the particle diafiltration to various materials.

Adulterated zirconium white (with the cubic zirconia of stabilized with yttrium oxide, with the stable cubic zirconia of scandium ...) be used as electrolyte usually or be used for functional cathode layer.

Therefore the contact between adulterated Zirconium oxide powder and the adulterated lanthanum-manganese uhligite powder is closely, and the point of contact number between these two kinds of powder is many.

Doping lanthanum-manganese the uhligite of cathode material can react with electrolytical doped zirconia, with the formation cenotype at the interface at them, particularly La ₂Zr ₂O ₇The pyrochlore-type phase, especially in the formula of LTM uhligite x less than 0.4, or even less than 0.3 o'clock.The existence of these phases reduces the performance of battery.

Thereby for improving the performance of SOFC, existence only forms a small amount of La to being suitable for when contacting with the doped zirconia powder ₂Zr ₂O ₇The needs of the doping lanthanum-manganese uhligite of pyrochlore-type phase.

Another object of the present invention is to address that need.

According to the present invention; by the consolidation product made by the LTM uhligite particularly the product of particle or block form realized these purposes; wherein L is meant lanthanum, and T is the element that is selected from the mixture of strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium and these elements, and M is meant manganese.

Product of the present invention can be pressed powder type especially and exist.The particulate size can be especially greater than 1 μ m, or greater than 10 μ m, or greater than 0.25mm, and/or less than 3mm.

This powder can comprise especially greater than 90 weight %, or greater than the consolidation particle of the LTM uhligite of the present invention of 95 weight % or basic 100 weight %.

Product of the present invention is consolidation, and promptly it also solidifies acquisition then by fusing.Though the preparation of fusing-congealed prod is known, the inventor's contribution is to find to make it possible to prepare the technology of the product that contains the LTM uhligite.Advantageously, product of the present invention can thereby be prepared with low expense and commercial quantities.

Product of the present invention can be an annealing product, or unannealed product, the product of promptly not heat-treating after it solidifies.

In addition, as following more detailed explanation, product of the present invention always produces still less pyrochlore-type La than the prior art products with identical chemical constitution with the contact of the Zirconium oxide powder of doped yttrium oxide the time ₂Zr ₂O ₇Phase.Therefore it is particularly well adapted for preparing the negative electrode of SOFC.

The content of gained LTM uhligite and character depend on the composition of initial charge especially.Yet product of the present invention is polycrystalline all the time.

In embodiments of the invention, outside the removal of impurity, the consolidation product has the LTM uhligite per-cent greater than 50%, and described uhligite has lanthanum, element T and manganese and divides other molar ratio l _p, t _pAnd m _p, use following representation:

x = \frac{t_{p}}{(l_{p} + t_{p})}

With

y = 1 - \frac{(l_{p} + t_{p})}{m_{p}}

X＞0, preferred x＞0.02, preferred x＞0.15, and/or x≤0.5, preferred x≤0.4, preferred x＜0.35, preferred x≤0.3, preferred x＜0.25; With

Y 〉=-0.1, preferred y 〉=-0.05, preferred y 〉=0, and/or y≤0.24, preferred y≤0.1.

Variable x and y are corresponding to (the La of the LTM uhligite of product of the present invention _(1-x)T _x) _(1-y)MnO _(3-δ)Atomic ratio x and y in the structure.

This specification sheets has provided the definition of the LTM uhligite per-cent of product hereinafter.

Preferably, product of the present invention comprises one and preferred a plurality of following optional feature:

Outside the removal of impurity, LTM uhligite per-cent is preferably greater than 90% greater than 70%, is preferably greater than 99%, more preferably greater than 99.9%, or even be 100%;

Obtain maybe can obtain product of the present invention by the inventive method of hereinafter describing in detail more;

Employed element T is selected from calcium, strontium, barium, magnesium and composition thereof.Element T is calcium and/or strontium preferably.

Foreign matter content is less than 1%, preferably less than 0.7%.

Advantageously, these character are improved the specific conductivity performance, make product be particularly suitable for the negative electrode of (choosing wantonly after grinding) preparation Solid Oxide Fuel Cell (SOFC).

Product of the present invention does not need to carry out anneal after cooling, and/or does not need through grinding.

The present invention also provides preparation to comprise the method for the consolidation product of LTM uhligite, wherein L is meant lanthanum (La), T is the element that is selected from the mixture of strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium and these elements, and M is meant manganese (Mn), and this method comprises following step:

A ') will provide the raw material of lanthanum, element T and manganese to mix, so that form initial charge;

B ') this initial charge is melted to obtain melt liquid;

C ') the described melt liquid of cooling solidifies fully up to it, so that obtain the consolidation product.

Thereby, conventional fusing-clotting method is only by regulating the composition of initial charge, make it possible to prepare the consolidation product of different size by melt liquid, outside the removal of impurity, described product has greater than 50%, is preferably greater than 70%, be preferably greater than 90%, more preferably greater than 99%, also more preferably greater than 99.9%, or even basic 100% LTM uhligite per-cent.

Technology prejudice has been run counter in this beat all especially discovery, and this prejudice causes those skilled in the art only to pay close attention to above-mentioned complexity and expensive method in the past.

Preferably, preparation method of the present invention also comprises a kind of and preferred multiple following optional overall characteristic:

Determine the amount of lanthanum, element T and manganese in selected element T and the initial charge, make at step c ') product that obtains when finishing meets the present invention;

Element T is the lanthanum doping agent that is selected from calcium, strontium, barium, magnesium and composition thereof.These doping agents significantly improve the electroconductibility of LTM uhligite;

At least a among element L, T and the M introduced with oxide form;

Provide the compound of element L, T and M account for altogether the initial charge composition greater than 90% and be preferably greater than 99% weight percent.These compounds preferably account for 100% of initial charge composition with impurity;

Provide the compound of L, T and M to be selected from SrO, SrCO ₃, La ₂O ₃, CaO, CaCO ₃, Y ₂O ₃, Yb ₂O ₃, MgO, MgCO ₃, CeO ₂, BaO, MnO ₂, MnO or Mn ₃O ₄

At step b ') in, plasma torch or fan heater do not used.Especially, use electric arc furnace or induction furnace.

In the first broad sense embodiment, the present invention relates to the product and the such particulate method of preparation of particle form.

Especially, the invention provides comprise step a '), b ') and c ') the preparation method, and step c ') comprise following step:

c ₁') melt liquid is dispersed into the drop form; With

d ₁') make described droplet solidification by contacting with oxygen-bearing fluid, so that obtain the consolidation particle.

Preferably this method is modulated so that obtain the particle of LTM perovskite product of the present invention.

Conventional dispersing method is only by regulating the composition of initial charge, particularly by winding-up or atomizing, therefore make it possible to begin to prepare particles of different sizes from melt liquid, outside the removal of impurity, described particle has greater than 50%, is preferably greater than 70%, more preferably greater than 90%, more preferably greater than 99%, also more preferably greater than 99.9%, even basic 100% LTM uhligite per-cent.

In the first broad sense embodiment, preparation method of the present invention preferably also comprises one and preferred more than a general option characteristic listed above and/or following particular characteristics:

At step b ₁') in, do not use plasma torch or fan heater.For example, use electric arc furnace.Advantageously, this has improved productive rate.In addition, the method for using plasma torch or fan heater usually makes to prepare and has greater than 200 μ m or at least greater than the particle of 500 μ m sizes;

At step c ₁') and/or steps d ₁') in, described melt liquid is contacted with oxygen-bearing fluid, described oxygen-bearing fluid preferably with steps d ₁') in employed oxygen-bearing fluid identical;

Described oxygen-bearing fluid, preferred gas, preferred air, comprise at least volume 20% or even the oxygen of volume 25% at least;

Dispersion and coagulation step are simultaneously;

Keep the contact between drop and the oxygen-bearing fluid, solidify fully up to described drop; With

The consolidation particle can be annealed.Preferably with described particle at 1050 ℃-1400 ℃, anneal under preferred about 1150 ℃ temperature, at high temperature soaking time is at least 30 minutes, is preferably greater than 2 hours, is preferably about 5 hours.More preferably, they under the atmosphere that comprises at least 20 volume % oxygen, preferably under air, are preferable under the barometric point and anneal.

Application grinding consolidation particle and/or it is carried out the selection operation of particle size for example by screening, makes that especially the particle that obtains has greater than 1 μ m on the estimation, or greater than 10 μ m and/or less than the size of 3mm.

In the second broad sense embodiment, the present invention relates to the product and the method for preparing such block of block form.

c ₂') melt liquid is cast in the mould;

d ₂') by cooling the liquid that is cast in the mould is solidified, to obtain the block of partial coagulation at least; With

e ₂') with the described block demoulding.

In the second broad sense embodiment, preparation method of the present invention preferably also comprises one and preferred more than a general option characteristic listed above and/or following particular characteristics:

At step b ₂') in, use induction furnace;

At step c ₂') in and/or steps d ₂') in and/or at step e ₂') after, the described melt liquid that is solidifying is directly or indirectly contacted with oxygen-bearing fluid, described oxygen-bearing fluid preferably comprise at least 20% or even at least 25% oxygen, preferably gas is more preferably air;

After with the block demoulding, begin described contact at once;

Keep described contact to solidify fully up to block;

Implementation step e before block solidifies fully ₂') the demoulding;

Block when having the rigidity that can keep its shape substantially, it is carried out the demoulding;

The rate of cooling of solidificating period melt liquid preferably less than 100K/s, is more preferably less than 50K/s all the time less than 1000K/s.When using cast iron mould or graphite jig, rate of cooling is preferably less than 1K/s;

At step e ₂') after, the block of the demoulding is annealed.Preferably, with this block at 1050 ℃-1400 ℃, anneal under the preferred 1150 ℃ temperature, at high temperature carry out the soaking of certain time length, this time length reaches the moment meter on soaking temperature (on the surface of this block and in the core of this block) from whole block, be preferably greater than 30 minutes, be preferably greater than 2 hours, preferred about 5 hours.More preferably, this block under the atmosphere that contains at least 20 volume % oxygen, preferably under air, is preferable under the barometric point and anneals; With

To choose the in flakes broken or powder of annealed demoulding block wantonly.

No matter consider which type of embodiment, all can have the phase except that the LTM uhligite, and the impurity that produces by raw material.

In preferred embodiments, impurity is all elements except the combination of lanthanum, element T and manganese and these elements.

Especially, can find following surface element: Al as impurity; Si; Zr; Na; And Fe, or even the Ba when element T does not comprise barium, strontium, magnesium, yttrium, ytterbium, cerium or calcium respectively; Sr; Mg; Y; Yb; Ce or Ca.Preferably, in oxide form, the impurity total weight percent preferably less than 0.7% weight, is more preferably less than 0.4% less than 1%.More preferably:

Al ₂O ₃＜0.5%, Al preferably ₂O ₃＜0.15%, more preferably Al ₂O ₃＜0.1%; And/or

SiO ₂＜0.1%, SiO preferably ₂＜0.07%, preferred SiO ₂＜0.06; And/or

ZrO ₂＜0.5%, preferred ZrO ₂＜0.1%, ZrO preferably ₂＜0.05%; And/or

Na ₂O＜0.1%, preferred Na ₂O＜0.07, preferred Na ₂O＜0.05%; And/or

Fe ₂O ₃＜0.05％。

At last, the present invention relates to by the inventive method preparation or consolidation product that is suitable for preparing or the application of consolidation product of the present invention in the negative electrode preparation of Solid Oxide Fuel Cell (SOFC).

Outside the removal of impurity, LTM uhligite per-cent uses following formula (1) definition:

T=100 * (A _LTM)/(A _LTM+ A _{Inferior looks}) (1)

Wherein:

A _LTMBe the diffraction main peak of LTM uhligite phase of the no deconvolution processing that records on x-ray diffraction pattern or the area of main multiplet, this diffractogram is obtained by the D5000 diffractometer type device that is equipped with copper DX pipe from supplier Bruker; With

A _{Inferior looks}The area of the diffraction main peak of the inferior looks that is on identical diffractogram and records when not having deconvolution processing or main multiplet.Inferior looks is the less important phase that has the main peak or the multiplet of maximum area when ignoring the LTM uhligite.Especially, La ₂MnO ₄Can be the inferior looks of on x-ray diffraction pattern, determining mutually.

Multiplet is partly overlapping a plurality of peak.For example, the multiplet that is made of two peaks is bimodal, and the multiplet that is made of three peaks is a triplet.

Describe the method for the first broad sense embodiment below in detail according to the present invention.

At step a ₁') in, by (particularly oxide compound or the carbonate form) compound of lanthanum, element T and manganese or by the precursor of element lanthanum, T and manganese, form and be suitable for preparing particulate initial charge of the present invention.Can be by adding the pure oxide compound or mixture, particularly SrO, the SrCO of oxide compound and/or precursor ₃, La ₂O ₃, CaO, CaCO ₃, Y ₂O ₃, Yb ₂O ₃, MgO, MgCO ₃, CeO ₂, BaO, MnO ₂, MnO or Mn ₃O ₄Regulate composition.The use of oxide compound and/or carbonate improves the availability that forms the uhligite requisite oxygen, and is preferred therefore.

In fact identical in the consolidation product of the amount of lanthanum, element T and manganese and preparation in the initial charge.During the fusing step, some these compositions are volatilizable, and the amount of described composition can change with melting condition.Based on general knowledge,, how to those skilled in the art will know that the amount of regulating these compositions in the initial charge according to amount required in the consolidation product or the melting condition implemented perhaps by carrying out simple routine experimentation.

The particles of powder size of using can be those that run into usually in the consolidation method.

Except the compound that element lanthanum, T and manganese are provided, basic mixture also can comprise other compound, introduces these other compounds and carries out the contrast of specified property in order to the particle to preparation.

Yet the preferred compound of not introducing in initial charge on one's own initiative except the compound that element lanthanum, T and manganese are provided is not particularly initiatively introduced except La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO, Mn ₃O ₄, CaO, CaCO ₃, Y ₂O ₃, Yb ₂O ₃, MgO, MgCO ₃, CeO ₂, the compound outside the BaO, other element exists as impurity.In embodiments, La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO, Mn ₃O ₄, CaO, Y ₂O ₃, Yb ₂O ₃, MgO, CeO ₂, BaO and their precursor total amount account for initial charge greater than 99 weight %.

Preferably, provide the compound of element lanthanum, T and manganese to be selected from La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO, Mn ₃O ₄, CaO, CaCO ₃With their precursor, the total amount of these compositions preferably account for initial charge greater than 99 weight %.Also preferably, in initial charge, do not introduce on one's own initiative except that La ₂O ₃, SrO, SrCO ₃, MnO ₂, MnO, Mn ₃O ₄, CaO, CaCO ₃Outside compound, other element is that impurity exists.

For improving LTM uhligite per-cent, the preferably approaching described molar ratio that needs the uhligite of preparation of the molar ratio of element L, T and M in the initial charge.

Therefore, in initial charge, element L, T and Mg divide other molar ratio l _d, t _dAnd m _d, with respect to ratio l _d, t _dAnd m _dThe molar percentage meter of total amount, preferred satisfy below condition:

k ₁. (1-x). (1-y)≤l _d/ m _d≤ k ₂. (1-x). (1-y) (1) and/or

k ₁.x.(1-y)≤t _d/m _d≤k ₂.x.(1-y)(2)

Wherein

The value of x and the desirable above-mentioned qualification of y, especially: 0＜x≤0.5 and-0.1≤y≤0.24

K ₁Equal 0.8, preferably equal 0.9; With

K ₂Equal 1.2, preferably equal 1.1.

Naturally, these k ₁And k ₂Value is those values of using under the operational condition of establishing, promptly ignores the transition phase between different the composition and ignores initial period.If the composition that desired product is hinting initial charge is compared with the composition that is used to prepare before-mentioned products and changed, then be necessary to consider the residual of before-mentioned products in the stove.Yet, those skilled in the art will know that and how correspondingly regulate initial charge.

At step b ₁') in, preferably in electric arc furnace, initial charge is melted.Electric smelting makes it possible to prepare a large amount of particles with favourable efficient.

For example, can use Heroult type electric arc furnace, this electric arc furnace has two electrodes and has the container that about 0.8 meter (m) diameter also can hold about 180kg melt liquid.Voltage is preferably 140V-180V, and power is about 240 kilowatts (kW), and energy is 1150kWh/t-2800kWh/t.

Yet, can expect all known stoves, for example the Heroult stove of induction furnace, plasma furnace or other type needs only them and can make the complete fusion of initial charge.And so nonessential, can also improve the stirring quality by carrying out bubbling by described in the FR 1 208 577 with oxidizing gas (for example air or oxygen).Particularly can improve the quality that melt liquid is stirred by carrying out bubbling with the gas that comprises 35 volume % oxygen.

At step b ₁') when finishing, all initial charge is a liquid form.

At step c ₁') in, will be in and be preferably greater than 1600 ℃ and preferably less than 2200 ℃, the melt liquid materials flow that is more preferably less than 1800 ℃ temperature when element during for strontium is dispersed into the small droplets form.

Can jet and pass the melt liquid materials flow and produce dispersion.Yet can expect any other method of atomized molten liquid well known by persons skilled in the art.

In steps d ₁') in, by with oxygen-bearing fluid, preferred gas more preferably contacts with air and/or steam and changes drop into solid particulate.Oxygen-bearing fluid preferably contains at least 20 volume % or even the oxygen of at least 25 volume %.

This method is modulated, make the drop of melt liquid when forming, contact with oxygen-bearing fluid at once.More preferably, disperse (step c ₁') and solidify (steps d ₁') be substantially simultaneously, described melt liquid disperses by the oxygen-bearing fluid that is suitable for making this liquid cooling and solidify.

Preferably, do not use except by contact the solidification mode cooling off with oxygen-bearing fluid.Therefore, for example preferably do not use drop to face toward the super quenching method that the cool metal wall sprays with melt liquid.

Air under the winding-up room temperature is fully suitable.

Rate of cooling is the dependent variable of particle diameter.For this speed of the particle with 0.3mm size is about 1000K/s.Preferably rate of cooling is regulated, make particle with before returnable contacts at least in their peripheral region hardening.

In steps d ₁') when finishing, obtaining solid particulate of the present invention, described particle has the size of 0.01mm-3mm or 0.01mm-4mm according to dispersion condition.

Advantageously, in unexpected and unaccountable mode, melt liquid is contacted the LTM uhligite that makes it possible to obtain commercial quantities with low cost with oxygen-bearing fluid, outside the removal of impurity, the per-cent of this LTM uhligite is outstanding, reach greater than 90% and even greater than 99.9%, and need not annealing steps.

At optional later step e ₁') in, the consolidation particle is introduced in the stove with the thermal treatment of annealing.Advantageously, such annealing can further improve the per-cent of LTM uhligite.Therefore, this makes it possible to obtain to equal substantially 100% LTM uhligite per-cent (outside the removal of impurity).

Annealing temperature is preferably 1050 ℃-1400 ℃, more preferably 1100 ℃-1200 ℃ and also preferred about 1150 ℃.This temperature preferably kept being longer than 0.5 hour, preferably was longer than 2 hours and was preferably about 5 hours time length.Preferably under the atmosphere that contains at least 20 volume % oxygen, preferably under air, be preferable over the thermal treatment of annealing under about 1 environmental stress that clings to.

Consolidation particle of the present invention can be ground before or after annealing.In case of necessity, can be depending on the expectation application and carry out the selection of particle size.

Particle of the present invention can advantageously show various yardsticks, and the preparation method is not limited to obtain the uhligite powder of sub-micron sized.Therefore it is very suitable for industrial preparation.

At first, in mixing tank, following starting raw material is closely mixed:

By the CaO powder that supplier La Gloriette sells, this powder has greater than the purity of 93 weight % and has the underflow that 80 μ m sieve that pass through greater than 90%; With

The initial charge of the heavy 50kg that obtains is by this way poured in the Heroult type electrometal furnace.Use the long arc fusing with its fusion (voltage is 150V, and power is 225kw, and the energy that applies in an embodiment is that 1380kWh/t-2000kWh/t does not wait), so that melt whole mixtures then in complete and uniform mode.Working conditions is an oxidisability.

In case fusing casts melt liquid so that form materials flow fully.The temperature that records melt liquid during the casting is 1730 ℃-1850 ℃.

Dried compressed air under the environment for use temperature then, and jet with 1 crust-3 bar pressures is with broken materials flow and this melt liquid is dispersed into drop.

The air cooling drop of winding-up also condenses them with the consolidation particle form.Depend on the air blown condition, the consolidation particle can be made sphere or other form, can be hollow or solid.They have the size of 0.01mm-3mm or 0.01mm-4mm.

Carry out chemical analysis and measure mutually having sample less than 40 μ m median size after grinding with lanthanum-strontium-manganese uhligite.

Carry out chemical analysis with x-ray fluorescence.

Use x-ray diffraction pattern to measure the per-cent of lanthanum-strontium-manganese uhligite, described diffractogram is obtained by the D5000 diffractometer that is equipped with copper DX pipe from supplier Bruker.After consolidation, products obtained therefrom can comprise uhligite mutually and more a spot of other La for example mutually ₂MnO ₄

Use joint committee (ICDD) card, adopt conventional criterion to determine lanthanum-strontium-manganese uhligite phase by X-ray diffraction.For example, ICDD 01-089-8084 card is to be used for La _0.7Ca _0.3MnO _3-δThe card of lanthanum-calcium-manganese uhligite phase.

In fact, when showing below, x-ray diffraction pattern carries out the measurement of lanthanum-calcium-manganese uhligite per-cent:

Main lanthanum-calcium-manganese uhligite phase; With

Inferior looks and other possible less important phase.

Then, with EVA software (selling) and after deduction continuous background (background 0.8), can measure the main diffraction peak of lanthanum-calcium-manganese uhligite or the area of multiplet (no deconvolution processing) A by supplier Bruker _LTMWith the main diffraction peak of inferior looks or the area A of multiplet _{Inferior looks}(no deconvolution processing).Use formula (1) to calculate the per-cent of lanthanum-calcium-manganese uhligite then.

Therefore, if lanthanum-calcium-manganese (LCM) uhligite is the unique phase that exists in the x-ray diffraction pattern mutually, then uhligite per-cent equals 100%.

Table 4 has gathered the result who obtains before any annealing thermal treatment.

Table 4

Table 4 has shown the validity of the inventive method.

Under the condition product of embodiment 6 is heat-treated below then:

Temperature: 1150 ℃;

Soaking time under this temperature: 5 hours;

Atmosphere: the air under the barometric point (environmental stress).

After thermal treatment, outside the removal of impurity, this product has lanthanum-calcium-manganese uhligite per-cent of 100%.

Can be clear that in this point, method of the present invention is the feasible particle that simply and at an easy rate prepares commercial quantities in its first broad sense embodiment, described particle has very high lanthanum-element T-manganese uhligite level, and wherein element T is the element that is selected from strontium, calcium, magnesium, barium, yttrium, ytterbium and cerium.

Especially, this method make it possible to preparation by greater than 99.9% or even the particle that constitutes of 100% (outside the removal of impurity) lanthanum-element T-manganese uhligite, described uhligite has formula (La _1-xT _x) _1-yMnO _3-δ, wherein 0＜x≤0.5 and-0.1≤y≤0.24.

Purposes as fruit product needs, and then can reduce the particulate yardstick then, for example forms powder by they are ground.

Describe the method for the second broad sense embodiment of the present invention below in detail.

At step a ₂') in, press above with regard to step a ₁') described preparation initial charge, step a ₂') and step a ₁') have an identical preferred characteristics.

At step b ₂') in, initial charge is melted.Can use any smelting furnace.Can be by relating to step b ₁') description in or preferably above relate to step b ₂) description in illustrated the fusing.Especially, step b ₂) description the advantage of using induction furnace has been described.

At step b ₂') when finishing, all initial charge is a liquid form.

At step c ₂') in, press above with regard to step c ₂) illustrated, melt liquid is cast in the mould.Described casting melt liquid has and is preferably greater than 1600 ℃ and preferably less than 2200 ℃ temperature, is more preferably less than 1800 ℃ temperature when element T is strontium.

In steps d ₂') in, press above with regard to steps d ₂) described, the liquid that is cast in the mould is cooled off, up to the block that obtains partial coagulation at least, steps d ₂') have and steps d ₂) identical preferred characteristics, described characteristic is particularly related to and the contacting of oxygen-bearing fluid, speed of cooling and the type of cooling.

Advantageously,, melt liquid is contacted with oxygen-bearing fluid to improve the LTM uhligite per-cent in the consolidation block of the present invention significantly, reach basic 100% in unexpected and unaccountable mode.Thereby, need not annealing steps and obtain such per-cent.

In addition, the inventor finds that the rate of cooling of solidificating period is not to improve the deciding factor of LTM uhligite per-cent.Advantageously, thereby can use simple conventional method of cooling.

At step e ₂') in, press above with regard to step e ₂) illustrated, with the block demoulding, step e ₂') have and step e ₂) identical preferred characteristics, the situation that described characteristic is particularly related to the demoulding and contacts with oxygen-bearing fluid.

At optional step f ₂') in, press above with regard to step f ₂) illustrated, the block of the demoulding is put into stove with the thermal treatment of annealing, step f ₂') have and step f ₂) identical preferred characteristics, described characteristic is particularly related to annealing parameter.

Advantageously, such annealing can significantly improve LTM uhligite per-cent.Therefore outside the removal of impurity, can obtain greater than 99%, be preferably greater than 99.9% and even equal 100% LTM uhligite per-cent substantially, and, even any melt liquid can not be contacted with oxygen-bearing fluid, for example because the preparation block when the demoulding, solidified fully and in mould cooling period or casting during can not contact with oxygen-bearing fluid, also can be able to like this.

In order to obtain for example to be used to prepare the powder of the negative electrode of Solid Oxide Fuel Cell (SOFC), optionally subsequently the annealed block is pulverized and be ground to required particle size.Advantageously, method of the present invention makes it possible to prepare the particle with various yardsticks, and expense is low.

Preferably, at first the block of the demoulding is pulverized into the sheet of 0-5mm.To the described thermal treatment of annealing, subsequently it is ground to required particle size then.

Provide following embodiment for illustration purposes, described embodiment does not limit the present invention.The block for preparing test as follows.

At first, the starting raw material identical with employed those starting raw materials among the embodiment that relates to this particulate first broad sense embodiment closely mixed in mixing tank.

The gained initial charge is poured in the Heroult type electrometal furnace (except that embodiment 6 ₂' outer).Melt with its fusion (voltage is 180V, and the energy that applies does not wait for 1150kWh/t-1760kWh/t between embodiment), so that melt whole mixtures by long arc then by complete and uniform mode.Operational condition is an oxidisability.

In case fusing is cast to melt liquid in the cast iron mould in air fully.The temperature that records melt liquid during the casting is 1560 ℃-1700 ℃.

By mentioned above rate of cooling " Vr " is assessed (seeing Table 2).

Carry out chemical analysis and measure mutually having sample less than 40 μ m median size after grinding with lanthanum-calcium-manganese uhligite.

Carry out chemical analysis with x-ray fluorescence.

By with the first broad sense embodiment (seeing Table 4) in identical mode, determine that lanthanum-calcium-manganese uhligite is mutually and measure their per-cent.

Table 5 has gathered the result who obtains before any annealing thermal treatment.

Between melting period, do not blast gas.

Embodiment 6 ₂' relating to by making the block of preparation with the following method: described method utilization is according to the induction melting of FR 1430962, and the diameter of wire turn is 275mm, and power is 120kW-220kW, and the frequency that the aperiodicity producer provides is 100kHz-250kHz.

Table 5

Embodiment	Voltage (V)	The energy that applies (kWh/t)	The quality (kg) of the charging of fusing)	Mould-type	Vr (℃/s)	The yardstick (mm) of casting block
Embodiment	Voltage (V)	The energy that applies (kWh/t)	The quality (kg) of the charging of fusing)	Mould-type	Vr (℃/s)	The yardstick (mm) of casting block	1 ₂’	180	1400	50	Cast iron	＜0.1	D200，h150
2 ₂’	180	1400	50	Cast iron	＜0.1	D200，h150	1 ₂’	180	1400	50	Cast iron	＜0.1	D200，h150
2 ₂’	180	1400	50	Cast iron	＜0.1	D200，h150	3 ₂’	180	1760	50	Cast iron	＜0.1	D200，h150
4 ₂’	180	1150	40	Cast iron	＜0.1	D200，h150	3 ₂’	180	1760	50	Cast iron	＜0.1	D200，h150
4 ₂’	180	1150	40	Cast iron	＜0.1	D200，h150	5 ₂’	180	1700	40	Cast iron	＜0.1	D200，h150
6 ₂’	-	-	75	The wire turn of coil	＜0.1	D275，h190	5 ₂’	180	1700	40	Cast iron	＜0.1	D200，h150

In following table 5 ', the content of element lanthanum is with La ₂O ₃The form meter, the content of element calcium is in the CaO form, and the content of element manganese is in the MnO form.

Table 5 '

Table 5 ' shown the validity of the inventive method.This table shows that also (embodiment 6 when melting by induction ₂'), wherein the surface of demoulding block contacts with airborne oxygen quickly and (begins at the most after 20 minutes from solidifying in this embodiment, this moment, block did not solidify as yet fully), the per-cent of lanthanum-calcium in the finished product-manganese uhligite is very high, reach 99.9%, the therefore advantageously feasible thermal treatment of annealing becomes nonsensical.

Subsequently to embodiment 1 ₂', 2 ₂', 3 ₂' and 5 ₂' thermal treatment (table 6) of annealing.Casting block or the block that is crushed to the 0-5mm sheet annealed, and (embodiment 1 in thermal treatment ₂' and 2 ₂').In table 6, provided employed heat treatment parameter.In air, heat-treat.

According to relate to the LTM particle, be particularly related to lanthanum-calcium-mode in manganese particulate the foregoing description measures LTM uhligite per-cent.

Table 6

Table 6 shows that anneal causes lanthanum-calcium-manganese uhligite per-cent to significantly improve, up to basic 100%.

Can be clear that, the feasible block that simply and at an easy rate prepares commercial quantities of the method for the second broad sense embodiment according to the present invention, described block has very high-caliber lanthanum-element T-manganese uhligite, and wherein element T is the element that is selected from strontium, calcium, magnesium, barium, yttrium, ytterbium and cerium.

Especially, this method make it possible to preparation by greater than 99.9% or even the block that constitutes of the lanthanum-element T of 100% (outside the removal of impurity)-manganese uhligite, this lanthanum-element T-manganese uhligite has formula (La _1-xT _x) _1-yMnO _3-δ, wherein 0＜x≤0.5 and-0.1≤y≤0.24.

When element T was calcium, present method makes can prepare the block that contains lanthanum-calcium-manganese (LCM) uhligite especially, wherein:

" with La ₂O ₃The lanthanum of form meter " weight percent greater than 40.2%, be preferably greater than 43.3%, be preferably greater than 51.8%, more preferably greater than 56.8%, and/or,,, be more preferably less than 63.6% preferably less than 68.9% preferably less than 69.9% less than 70.8%; And/or

The weight percent of " in the calcium of CaO form " is preferably greater than 3.7% greater than 0.44%, and/or less than 16.1%, preferably less than 15.6%, preferably less than 10%, is more preferably less than 6.8%; And/or

The weight percent of " in the manganese of MnO form " is preferably greater than 29.6% greater than 28.7%, is preferably greater than 30.6%, more preferably greater than 32.6%, and/or less than 46%, preferably less than 41.8%, preferably less than 38.6%, is more preferably less than 36.6%.

If the purposes of block needs, then can reduce their yardstick then, for example, they form powder by being ground.

Consolidation LTM perovskite product is outstanding especially, and reason is, uses the La of the measured generation of above-mentioned criterion ₂Zr ₂O ₇The amount of pyrochlore-type phase is with the La that uses the LTM uhligite powder that obtains by the method outside the consolidation to produce under the same conditions ₂Zr ₂O ₇The amount of pyrochlore-type phase is compared, and is always lower.This performance even it seems the feature that will constitute product of the present invention.

The following is the method that is used to measure this performance.

The LTM uhligite powder that ten grams (g) are used to test closely mixes with the Zirconium oxide powder of 8 moles of % stabilized with yttrium oxide with 10g, and described LTM uhligite powder has the median size less than 1.5 μ m.Be included in 1375 ℃ of following cycles of 24 hours of soaking then, down the sheet grain of this mixture suppressed and sintering in high temperature.Measure the median size and the sintering heat treatment parameter of LTM powder, so that help to form La ₂Zr ₂O ₇The pyrochlore-type phase, thus outstanding LTM powder is in they the behavior difference when Zirconium oxide powder with 8 moles of % stabilized with yttrium oxide contacts.

Measure the La that comprises in the sintered sample by X-ray diffraction ₂Zr ₂O ₇The amount of pyrochlore-type phase is with respect to La in the sample ₂Zr ₂O ₇Pyrochlore-type phase and zirconic total amount are represented.Therefore this measurement is a measurement of comparison, is not quantitative measurment.

Careful use identical criterion and identical stabilized zirconia powder in, can be easy to carry out the contrast between the Different L TM uhligite powder.Preferably, all samples carries out sintering in identical stove, so that any residual quantity that restriction may cause because of the preparation method who waits to characterize sample.

Embodiment

Test below carrying out produces less La so that the consolidation perovskite product is described when at high temperature contacting with the Zirconium oxide powder that is stabilized ₂Zr ₂O ₇The ability of phase.

Described test comprises Zirconium oxide powder is closely mixed with adulterated lanthanum-manganese (LTM) uhligite powder that preparation sheet grain rises to high temperature then to promote La ₂Zr ₂O ₇The generation of phase.Measure the described amount that produces by X-ray diffraction then with respect to zirconium white amount in the sample.

At length, use following method.

Preparation is used for the sample of the correlated LTM of comprising powder as follows.

In glass beaker, use the stainless steel spatula sold 10g by supplier Tosoh TZ-8Y Zirconium oxide powder (with 8 moles of % stabilized with yttrium oxide and have 0.212 a μ m median size d ₅₀(recording) and 15.2m with sedimentation sreen analysis method ²The zirconium white of/g specific surface area) being used for one of correlated LTM uhligite powder with 10g mixes, up to color even, described LTM uhligite powder has the median size of 0.16-1.1 μ m, choose wantonly after using zirconium white bead with 16.5 moles of % ceria stabilized to grind in LME (1) type Netzsch mill, described zirconic bead has the particle size of 0.8mm-1mm.Then spiece is transferred in the agate mortar to use the agate mortar hand lapping, in glass beaker, all powder is mixed once more then with the stainless steel spatula.

Use the preparation of sheet grain press to have the sheet grain of 13mm diameter and basic 5mm thickness then: the 2.8g powder to be put into wherein and suppressed 1 minute down at 50,000 Ns (KN) with manual Weber press.

Then the sheet grain is placed on the aluminium saggar with lid.

This molectron is put in Naber 1800 stoves of being sold by supplier Nabertherm, be warming up to 1375 ℃ then and kept 24 hours, with 5 ℃ of/minute intensifications and with 5 ℃ of/minute coolings.

Make each agglomerating sheet grain attenuate in mill manifest the core of material thus then so that remove the thickness of about 2mm.At last the sheet grain is applied and polishes with transparent resin.

Use realizes the X-ray diffraction measurement from the D5000 device that is equipped with copper DX pipe of supplier Bruker.Produce x-ray diffraction pattern with 0.02 ° the step-length and the collection time in 4 seconds per steps.In fact, these figure make it possible to detect:

La ₂Zr ₂O ₇The pyrochlore-type phase locates to have its diffraction main peak (ICDD card 00-017-0450) 28.7 ° of 2 θ ≈; With

The cubic zirconia phase locates to have its diffraction main peak (ICDD card 00-027-0997 or 01-049-1642) 30.5 ° of 2 θ ≈.

Use EVA software (selling) then and after deduction continuous background (background 0.8), can measure La by supplier Bruker ₂Zr ₂O ₇The peak area of pyrochlore-type in 28.4 °＜2 θ＜29.1 ° angular ranges and the peak area of cubic zirconia in 29.3 °＜2 θ＜30.8 ° angular ranges.

Provide the result with following ratio form:

The correlated various LTM uhligite powder of institute are as follows:

-for example synthetic by the method beyond the consolidation, by the synthetic of precursor and comparative prior art powder that spray pyrolysis obtains by solid state sintering:

By (lanthanum of doping strontium) and the uhligite powder of manganese of supplier NexTech Materials with title LSM20-P sale; Hereinafter be referred to as " Comparative Examples 1 ";

By supplier Praxair with title (La _0.8Sr _0.2) _0.98(lanthanum of doping strontium) and the uhligite powder of manganese that the Mn oxide compound is sold; Hereinafter be referred to as " Comparative Examples 2 "; With

The applicant is by carrying out agglomerating La comprising in 1450 ℃ of following cycles of 10 hours of soaking ₂O ₃, SrCO ₃And MnO ₂The intimate mixture of powder hereinafter is called " Comparative Examples 3 " by the uhligite powder of solid state sintering synthetic (lanthanum of doping strontium) and manganese;

The powder of-consolidation perovskite product of the present invention:

The uhligite powder of consolidation of the present invention (lanthanum of doping strontium) and manganese is called above that " embodiment 1 ₂", it is not carried out any anneal (seeing Table 2 ');

Preamble is called that " embodiment 1 ₂" consolidation of the present invention (lanthanum of doping strontium) and the uhligite powder of manganese, in air, under 1150 ℃, it is carried out anneal (seeing Table 3) with soaking in 5 hours;

Be called above that " embodiment 1 ₁" consolidation of the present invention (lanthanum of doping strontium) and the uhligite powder of manganese, it is not carried out any anneal (seeing Table 1);

Be called the consolidation of the present invention (lanthanum of doping strontium) of " embodiment A " and the uhligite powder of manganese, it does not carried out any anneal; With

Be called the consolidation of the present invention (lanthanum of doping calcium) of " Embodiment B " and the uhligite powder of manganese, it does not carried out any anneal.

These uhligites have following chemical constitution:

Table 7

Embodiment	Form
Embodiment	Form	Comparative Examples 1	(La _0.8Sr _0.2) _0.99MnO _3-δ
Comparative Examples 2	(La _0.8Sr _0.2) _0.98MnO _3-δ	Comparative Examples 1	(La _0.8Sr _0.2) _0.99MnO _3-δ
Comparative Examples 2	(La _0.8Sr _0.2) _0.98MnO _3-δ	Comparative Examples 3	(La _0.81Sr _0.19) _0.99MnO _3-δ
A	(La _0.64Sr _0.36)MnO _3-δ	Comparative Examples 3	(La _0.81Sr _0.19) _0.99MnO _3-δ
A	(La _0.64Sr _0.36)MnO _3-δ	B	(La _0.79Ca _0.21)MnO _3-δ

As indicated above, prepare the sheet grain by each these powder and the zirconic mixture that is stabilized.

Table 8 has gathered with regard to the determined meter proportion of each sample that makes:

Table 8

Table 8 clearly illustrates, the powder of consolidation perovskite product of the present invention is compared with the powder of prior art perovskite product by the method gained outside the consolidation, has relatively little a lot of ratio:

In product of the present invention, even may detect less than La ₂Zr ₂O ₇The pyrochlore-type phase.

Therefore, advantageously, use the performance of the Solid Oxide Fuel Cell of these products to improve.

In addition, (embodiment 1 for Fig. 8 ₂) show that annealing steps does not change the favourable behavior of product of the present invention.Therefore, after annealing, product of the present invention keeps being different from Comparative Examples.

As indicated above, the LTM perovskite product is when contacting with zirconium white, and they can also produce disadvantageous T _aZr _bO _cThe type phase, a, b and c are integers.As by as shown in the following embodiment, each T _aZr _bO _cThe amount of type phase is based on this T _aZr _bO _cType mutually and the total amount meter of cubic zirconia, for consolidation product of the present invention all the time less than for non-consolidation product according to prior art.

Be used to measure T _aZr _bO _cThe method of the amount of type phase is similar to that preamble describes is used to measure La ₂Zr ₂O ₇The method of the amount of pyrochlore-type phase.

For example, when the element T of LTM uhligite is strontium (Sr), records this and be SrZrO mutually ₃X-ray diffractogram shows:

SrZrO ₃The type phase has its main peak for 30.8 ° at 2 θ ≈;

The cubic zirconia phase has its main peak (ICDD card 00-027-0997 or 01-049-1642) 30.5 ° of 2 θ ≈.

Use EVA software (selling) then and after deduction continuous background (background 0.8), can measure SrZrO by supplier Bruker ₃The peak area of type in 30.5 °＜2 θ＜31.2 ° angular ranges and the peak area of cubic zirconia at 29.3 °＜2 θ＜30.8 ° angular ranges.

Provide the result with following ratio form:

Provided the various LSM uhligite powder that compare below:

The applicant is by carrying out agglomerating La comprising in 1450 ℃ of following cycles of 10 hours of soaking ₂O ₃, SrCO ₃And MnO ₂The intimate mixture of powder hereinafter is called " Comparative Examples 4 " by (lanthanum of doping strontium) and the uhligite powder of manganese of solid state sintering synthetic comparative;

Be called the consolidation of the present invention (lanthanum of doping strontium) of " Embodiment C " and the uhligite powder of manganese, it does not carried out any anneal.

These uhligites have following chemical constitution:

Table 9

Embodiment	Form
Embodiment	Form	Comparative Examples 4	(La _0.63Sr _0.37)MnO _3-δ
C	(La _0.63Sr _0.37)MnO _3-δ	Comparative Examples 4	(La _0.63Sr _0.37)MnO _3-δ

Table 10 has gathered with regard to the determined ratio of the sample of each preparation " area (SrZrO ₃)/(area (SrZrO ₃)+area (cubic zirconia)) " measuring result.

Table 10

Embodiment	Area (SrZrO ₃)/(area (SrZrO ₃)+area (cubic zirconia)) ratio
Embodiment	Area (SrZrO ₃)/(area (SrZrO ₃)+area (cubic zirconia)) ratio	Comparative Examples 4	0.068
C	0	Comparative Examples 4	0.068

Table 10 clearly illustrates, the powder of LSM uhligite consolidation product of the present invention is compared with the powder of perovskite product by the other method gained beyond the consolidation, has relatively little a lot of area (SrZrO ₃)/(area (SrZrO ₃)+area (cubic zirconia)) ratio.In product of the present invention, even may detect less than SrZrO ₃Phase.

Advantageously, use the performance of the Solid Oxide Fuel Cell of these products therefore to be improved.

Certainly, the invention is not restricted to described embodiment, described embodiment provides with illustrative and non-limiting example.

Especially, product of the present invention is not limited to any specific shape or yardstick.

Claims

1. comprise the consolidation product of LTM uhligite, L is meant lanthanum, and T is the element that is selected from the mixture of strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium and these elements, and M is meant manganese.

2. according to the consolidation product of aforementioned claim, described uhligite has the molar ratio l of lanthanum, element T and manganese respectively _p, t _pAnd m _p, make note do:

X=t _p/ (l _p+ t _p) and y=1-(l _p+ t _p)/m _p

Then: x＞0 and/or x≤0.5; With

Y 〉=-0.1 and/or y≤0.24.

3. according to the consolidation product of aforementioned claim, x≤0.4 wherein.

4. according to the consolidation product of last claim, wherein:

X＞0.02 and/or x＜0.35; And/or

-0.05≤y and/or y≤0.1.

5. according to the consolidation product of last claim, x≤0.3 wherein.

6. according to the consolidation product of last claim, wherein:

0.15＜x and/or x＜0.25; And/or

·0≤y。

7. according to arbitrary consolidation product in preceding claim, this molten product with fixed attention has the LTM uhligite per-cent greater than 50% outside the removal of impurity.

8. according to the consolidation product of last claim, wherein outside the removal of impurity LTM uhligite per-cent greater than 90%.

9. according to the consolidation product of last claim, wherein outside the removal of impurity LTM uhligite per-cent greater than 99%.

10. according to the consolidation product of last claim, wherein outside the removal of impurity LTM uhligite per-cent greater than 99.9%.

11. according to the consolidation product of last claim, described uhligite is formula (La _1-xSr _x) _1-yMnO ₃Lanthanum-strontium-manganese uhligite, wherein 0＜x≤0.5 and-0.05≤y≤0.24, x and y are atomic ratio.

12. according to the consolidation product of last claim, in the formula of wherein said lanthanum-strontium-manganese uhligite:

(x＜0.5) and (0≤y and/or y≤0.1).

13. according to the consolidation product of last claim, in the formula of wherein said lanthanum-strontium-manganese uhligite:

(0.15＜x and/or x＜0.35).

14. according to the consolidation product of last claim, the formula of wherein said lanthanum-strontium-manganese uhligite is:

x＜0.25。

15. according to arbitrary consolidation product in preceding claim, element T is the lanthanum doping agent that is selected from calcium, strontium, barium, magnesium and composition thereof.

16. according to the consolidation product of last claim, employed element T is calcium and/or strontium.

17. according to the consolidation product of last claim, it has following chemical constitution by weight percentage, and altogether 100%:

36%＜with La ₂O ₃The lanthanum of form meter＜70.7%;

0%＜in strontium＜25.8% of SrO form;

29.3%＜in manganese＜41.2% of MnO form; With

Impurity＜0.7%.

18. according to the consolidation product of last claim, it has following chemical constitution by weight percentage, and altogether 100%:

38.4%＜with La ₂O ₃The lanthanum of form meter＜69.7%;

0%＜in strontium＜25.4% of SrO form;

30.3%＜in manganese＜37.2% of MnO form; With

Impurity＜0.7%.

19. according to the consolidation product of last claim, it has following chemical constitution by weight percentage, and altogether 100%:

47.9%＜with La ₂O ₃The lanthanum of form meter＜69.7%;

0%＜in strontium＜17% of SrO form;

30.3%＜in manganese＜35.7% of MnO form; With

Impurity＜0.7%.

20. according to the consolidation product of last claim, it has following chemical constitution by weight percentage, and altogether 100%:

47.9%＜with La ₂O ₃The lanthanum of form meter＜61.6%;

6.7%＜in strontium＜17% of SrO form;

31.5%＜in manganese＜35.7% of MnO form; With

Impurity＜0.7%.

21. according to the consolidation product of last claim, it has following chemical constitution by weight percentage, and altogether 100%:

53.9%＜with La ₂O ₃The lanthanum of form meter＜61.6%;

6.7%＜in strontium＜11.8% of SrO form;

31.5%＜in manganese＜34.7% of MnO form; With

Impurity＜0.7%.

22. according to arbitrary consolidation product in preceding claim, after cooling not to its anneal thermal treatment and/or itself and without any grinding.

23. according to arbitrary consolidation product in preceding claim, it is the block form that has greater than 1mm thickness.

24. according to the consolidation product of last claim, it is the block form that has greater than 5cm thickness.

25. according to each consolidation product in the claim 1 to 22, it is a particle form.

26. according to the consolidation product of last claim, described particle has the size less than 4mm.

27. according to arbitrary consolidation product in preceding claim, it can be by obtaining according to each method in the claim 28 to 53.

28. comprise the preparation method of the consolidation product of LTM uhligite, L is meant lanthanum (La), T is the element that is selected from the mixture of strontium, calcium, magnesium, barium, yttrium, ytterbium, cerium and these elements, and M is meant manganese (Mn), and this method comprises following step:

A ') will provide the raw material of lanthanum, element T and manganese to mix, to form initial charge;

B ') this initial charge is melted to obtain melt liquid;

C ') cools off this melt liquid and solidify fully, so that obtain the consolidation product up to it.

29. according to the method for last claim, wherein determine the amount of lanthanum, element T and manganese in the initial charge, make at step c ') the consolidation product that obtains when finishing meets in the claim 22 to 26 each.

30. according to two direct each methods in preceding claim, wherein provide the compound of element L, T and M account for altogether the initial charge composition greater than 90 weight %.

31. according to the method for last claim, wherein provide the compound of element L, T and M account for altogether the initial charge composition greater than 99 weight %.

32., wherein provide the compound of element L, T and M and the 100 weight % that impurity accounts for the initial charge composition altogether according to the method for last claim.

33., wherein provide the compound of element L, T and M to be selected from: SrO according to each method in the claim 28 to 32; SrCO ₃La ₂O ₃CaO; CaCO ₃Y ₂O ₃Yb ₂O ₃MgO; MgCO ₃CeO ₂BaO; MnO ₂MnO or Mn ₃O ₄

34. according to each method in the claim 28 to 33, wherein element L, T and M divide other molar ratio l _d, t _dAnd m _d, in based on ratio l _d, t _dAnd m _dThe molar percentage of total amount meter, condition below satisfying:

k ₁. (1-x). (1-y)≤l _d/ m _d≤ k ₂. (1-x). (1-y) (1) and/or

k ₁.x.(1-y)≤t _d/m _d≤k ₂.x.(1-y) (2)

Wherein 0＜x≤0.5 and-0.1≤y≤0.24, k ₁Equal 0.8, k ₂Equal 1.2.

35. according to the method for last claim, wherein k ₁Equal 0.9, and k ₂Equal 1.1.

36. according to each method in the claim 28 to 35, wherein at step b ') in, when being particle form, uses the consolidation product electric arc furnace, perhaps use induction furnace when the consolidation product is block.

37., wherein the consolidation product is annealed according to each method in the claim 28 to 36.

38. method according to last claim, wherein anneal under the soaking temperature in 1050 ℃ of-1400 ℃ of scopes, all thermal endurance is at least 30 minutes under this temperature, when the consolidation product is block form, in case all the consolidation product reaches soaking temperature, just begins soaking.

39., wherein under the atmosphere that contains at least 20 volume % oxygen, anneal according to two direct each methods in preceding claim.

40. according to each method in the claim 28 to 39, wherein step c ') comprise following step:

c ₁') melt liquid is dispersed into the drop form; With

41. according to the method for last claim, wherein at step c ') in, described melt liquid is contacted with oxygen-bearing fluid.

42. according to two direct each methods in preceding claim, wherein at step c ₁') and/or steps d ₁') in, described melt liquid is contacted with the oxygen-bearing fluid that contains 20 volume % oxygen at least.

43. according to each method in the claim 40 to 42, wherein dispersion steps and coagulation step are simultaneously.

44. according to each method in the claim 40 to 43, wherein keep the contact between drop and the oxygen-bearing fluid, solidify fully up to described drop.

45. according to each method in the claim 28 to 39, wherein step c ') comprise following step:

c ₂') melt liquid is cast in the mould;

e ₂') with the described block demoulding.

46. according to the method for last claim, at step c ₂') in and/or in steps d ₂') in and/or at step e ₂') after, the melt liquid that is solidifying is directly or indirectly contacted with oxygen-bearing fluid.

47. according to the method for last claim, wherein oxygen-bearing fluid is a gas.

48. according to the method for claim 46 or claim 47, wherein oxygen-bearing fluid is an air.

49., wherein after with the block demoulding, begin described contact at once according to each method in the claim 46 to 48.

50., wherein keep this contact to solidify fully up to block according to each method in the claim 46 to 49.

51. according to each method in the claim 45 to 50, wherein implementation step e before block solidifies fully ₂') the demoulding.

52. according to each method in the claim 45 to 51, in case just it is carried out the demoulding when wherein block has the rigidity that is enough to keep substantially its shape.

53. according to each method in the claim 45 to 52, wherein the rate of cooling of the melt liquid of solidificating period is all the time less than 1000K/s.

54. according to each method in the claim 45 to 53, after the wherein optional annealing, the in flakes broken or powder with the block of the demoulding.

55. each consolidation product or the purposes of consolidation product in the negative electrode preparation of Solid Oxide Fuel Cell (SOFC) in the claim 1 to 27 by obtaining according to each method in the claim 28 to 54 maybe can obtain.