Zirconium oxide and way of its production. RU patent 2442752.

FIELD: chemical industry.

SUBSTANCE: invention refers to powdered zirconium oxide, way of its production and its application in fuel cells, notably for production of electrolyte substances for ceramic fuel cells. The powdered zirconium oxide containing up to 10 mole % of at least one metal oxide from the scandium, yttrium groups, the group of rare-earth elements and/or their mixtures is characterized by the extension density from 1.2 to 2.5 g/cm³ measured according to ASTM B 417.

EFFECT: powdered zirconium oxide characterized by a high electrical conductance and a high mechanical strength after agglomerating up to gas-impermeable bodies, and an efficient way of its production.

37 cl, 3 dwg, 1 tbl, 8 ex

The invention relates to a powdery oxide of zirconium containing metal oxides from the group of scandium, yttrium, rare earth elements and/or their mixtures, method of production thereof, and their use in fuel cells, in particular, to obtain an electrolyte substrates for ceramic fuel cells.

Pure zirconium oxide (ZrO₂) is located in three different versions. The cubic phase of high temperature becomes below 2300°C in a metastable tetragonal zirconium oxide, and between 1200°C and 950°C see the transition of tetragonal to monoclinic ZrO₂. Transformation between monoclinic phases and phases for high temperature heating and cooling associated with uneven volume changes.

Sintering of Zirconia occurs in the temperature region, which obviously passes through the reversible temperature monoclinic-tetragonal transformation phases. To prevent reverse transformation into the monoclinic phase, requires stabilization of the high temperature modifications with other oxides. Stabilized Zirconia are then from room temperature to the temperature of the melt in the same stabilized modification, i.e. for the manufacture of ceramic building components during cooling to prevent drastic changes in volume, Ullmann''s Encyclopedia of Industral Chemistry, that A28, 1996, s FF., Römpp Lexikon Chemie, 10th edition, 1999, s. For ceramic building elements used stabilized or partially stabilized powder of zirconium oxide. Moreover, the oxide stabilizer can form a solid solution with Zirconia. This requirement is met when using oxides of alkaline-earth metals, scandium oxide, yttrium oxide and individual oxides of the lanthanides and actinides. The amount of stabilizer depends on the desired characteristics and the type of oxide. The lack of homogeneity of the stabilizer in the lattice ZrO₂lead to the presence of unwanted monoclinic, that is not stable parts of phases. Depending on the concentration, type and quantity of the oxide of the stabilizer and the applied sintering conditions can be obtained commensurate with the materials of zirconium oxide with improved characteristics, which are used, for example, in a constructive and construction elements in modern mechanical engineering, medicine, cutting tools and insulating layers.

In recent years, the oxides of zirconium doped yttria, apply more upon receipt of ceramic fuel cells. An important characteristic of substrates for ceramic fuel cells derived from oxides of zirconium, is their electrical conductivity, which the traveler has a significant impact on the capacity of the fuel cell.

According to international application WO 03/051790 stabilized Zirconia receive two main ways in different versions.

According to the wet method from aqueous or organic solutions or suspensions of the primary substances of Zirconia and stabilizer separated solids, which contain both metals. As a rule, separates solids by co-precipitation and filtration of hydroxides. However, also use other methods of separation, such as, for example, a method Sol-gel method, the evaporation method, the spray pyrolysis and hydrothermal method. After separation of the precipitated precursors them then calicivirus at temperatures between 500 and 1500°C.

In U.S. patent US 3957500 describe the process of co-precipitation to obtain a homogeneous mixture of zirconium hydroxide and yttrium. After calcined at a temperature of from 900 to 1500°C for 1 to 10 hours is formed of stabilized Zirconia.

Such a typical commercial process described in U.S. patent US 4810680,

in which the basic carbonate, zirconium and yttrium carbonate is dissolved in dilute hydrochloric acid. Then hydroxides Coosada by adding ammonia or sodium hydroxide. Hydroxide mixture is washed, dried and calicivirus at a temperature of from 680 to 980°C.

In the German patent application DE 10138573 describe nanosc the regular pyrogenic obtained tetragonal zirconium oxide, stabilized yttrium (YSZ), in powder form and the process of its receipt. Moreover, aqueous and/or alcoholic solutions of the precursors of zirconium and yttrium, such as, for example, nitrates and propionate through the nozzle into the reaction tube, in which there is an oxygen-hydrogen flame of hydrogen and air is sprayed and then fired at temperatures from 800 to 1000°C.

In U.S. patent US 5750459 describe obtaining gels or spherical, or microspherical particles by dripping a solution of yttrium nitrate/zirconium in the solution of ammonium hydroxide. After separation and washing of the obtained gel or agglomerates with water, and then calcined at temperatures above 550°C receive spherical and microspheric stable powder of zirconium dioxide. A high degree of filtering of the precursor gel is a major disadvantage compared to the traditional process of deposition of the hydroxide.

The disadvantages of these wet methods is that produce large quantities of wastewater. Besides always need washing in large volumes to remove all by-products. If, however, washing is not full, then at the time of calcination of the precursor form of exhaust gases, such as HCl/Cl₂or NO_x.

Other methods of obtaining stable powder ZrO₂ is a mixed-oxide process or a solid phase process. In this way a mixture of zirconium dioxide and stabilizers homogenized and then is sintered to a stable powder ZrO₂. The process of solids is the simplest and least expensive. In contrast to the wet methods, except for the recycled water or water vapor, are there any by-products or contaminated waste waters and gases.

As disadvantages of the method called high-temperature sintering >1300°C and low homogeneity of the powders after sintering contain from 25 to 30% vol. the monoclinic phase. To minimize part of the monoclinic phase, the products are re-crushed and maintain a uniform temperature in several stages, which significantly increases the cost of the product. Therefore, stable powder ZrO₂hard to get under mixed-oxide methods.

In U.S. patent US 4542110 describe the process of obtaining sintered bodies through grinding in the wet state of a mixture of Zirconia and yttria adding SiO₂and Al₂O₃as an aid to sintering and subsequent drying and sintering the mixture for 10 to 120 minutes at temperatures >1300°C, preferably between 1400°C and 1500°C. After further stirring and maintaining uniform temperature increases unicasa part of the phase, at least 95 vol.%.

In U.S. patent US 4360598 describe the process of obtaining YSZ ceramics by mixing amorphous Zirconia with yttria or yttrium - containing salt subsequent sintering. After sintering at temperatures from 1000 to 1550°C receive the ceramic body, which contain predominantly tetragonal and cubic Zirconia.

In the European patent EP 1076036 describe the receipt of Zirconia stabilized with yttrium or other metals by fusion of the primary substances in the high-frequency or medium-frequency furnaces at temperatures from 2200 to 3000°C.

In GDR patent DD 96467 describe stabilized cubic zirconium dioxide, which is obtained by mixing the basic zirconium carbonate and stabilizing additives, such as calcium oxide or yttrium, and then sintering at 800°C for 3 hours.

In the international application WO 03/051790 describe the process of obtaining a tetragonal or a mixture of tetragonal and cubic Zirconia.

The disadvantage of the powder obtained according to the prior art by mixed-oxide process is its lack of homogeneity of the stabilizers in the crystal lattice. In order, however, to provide sufficient stabilization required high sintering temperature. However, this drive is t to the high cost of obtaining, also due to the addition of the necessary technological stages (crushing, screening). In addition, the high sintering temperature lead to undesirable low values BETH and low activity sintering powder. These powders because of their low electrical conductivity and insufficient activity sintering is not suitable for use in ceramic fuel cells.

Therefore, the objective of the invention is the finding of a powder of zirconium oxide for use in ceramic fuel cells that exhibit high electrical conductivity and high mechanical strength after sintering to gastight phone

In addition, the objective of the proposed invention to provide an economical method of producing powder of zirconium oxide.

The solution is powdered zirconium oxide containing up to 10 mol.%, at least one of the oxides of metals from the group of scandium, yttrium, rare earth elements and/or mixtures thereof, which has a bulk density of at least 1.2 to 2.5 g/cm³measured according to ASTM 417.

Preferably proposed according to the invention powdered oxides of zirconium have a bulk density of at least 1.2 to 2.3 g/cm³, particularly preferably from 1.6 to 2.0 g/cm³especially preferably at least from 1.3 to 1.9 g/cm³and, in particular, preferably from 1.5 to 1.7 g/cm³. Proposed according to the invention, the oxides of zirconium differ preferably a bulk density of at least 1.5 to 2.5 g/cm³especially preferably, at least, from 1.6 to 2.3 g/cm³.

Proposed according to the invention, the oxides of zirconium are particularly well suited as the primary materials for the production of substrates, which are used in ceramic fuel cells on the basis of their high electrical conductivity. A good result is obtained if the oxides of zirconium containing from 3 to 10 mol.% yttrium oxide as a stabilizer. Preferably proposed according to the invention, the oxides of zirconium containing from 3 to 6 mol.%, particularly preferably 3 to 5 mol.% and, in particular, preferably from 3 to 4 mol.% yttrium oxide.

Proposed according to the invention, the oxides of zirconium may contain as a stabilizer is also preferably from 3 to 10 mol.%, preferably from 3 to 7 mol.%, especially preferably 4 to 6 mol.% oxide ytterbium (Yb₂O₃).

Proposed according to the invention, the oxides of zirconium preferably have a value of D₉₀powder particles from 0.5 to 1.2 μm, preferably from 0.5 to 0.9 μm, particularly preferably from 0.6 to 0.9 μm, measured in accordance With ASTM 1070.

Offer the config according to the invention the powder also differs in its specific surface (BET). Preferably the powders have a value BET, measured according to ASTM D of 3,663, from 5 to 18 m²/g, preferably from 5 to 15 m²/g, preferably from 10 to 16 m²/g, preferably from 7 to 13 m²/g, particularly preferably from 9 to 12 m²/year

Proposed according to the invention the zirconium dioxide has a very high monoclinic part of phases. Unexpectedly and in comparison with the prior art, after the change of volume with reverse transformation phases, going from monoclinic to tetragonal, are suitable fully or partially stabilized powder with a very slight monoclinic parts of phases, up to a maximum of 10% vol. for ceramic building elements proposed according to the invention the powders of Zirconia, despite monoclinic part of phases, up to 80 vol.%, suitable for ceramic substrates and in particular for applications in the ceramic electrolyte fuel cells. Proposed according to the invention the powders of zirconium oxide can be from 5 to 80 vol.% monoclinic parts of the phases, preferably the powders are from 20 to 80 vol.%, preferably from 20 to 60 vol.%, particularly preferably from 40 to 75 vol.%, in particular, preferably from 45 to 70 vol.% monoclinic parts of phases. Special proposed according to the invention, the powders are from 40 to 55 vol.%, preferably from 45 to 55 vol.% m is naklonnykh parts of the phase.

In addition, the invention relates to efficient and cost-effective way of getting proposed according to the invention the oxides of zirconium.

Therefore, an object of the invention is also a method of producing Zirconia, doped metal oxides from the group of scandium, yttrium and rare earth elements and/or mixtures thereof, comprising the following stages:

a) preparation of an aqueous suspension of zirconium oxide and the corresponding metal oxide in the desired stoichiometric ratio, including stabilizing the suspension by means of a disperser;

b) homogenization of the suspension by grinding with the use of intensifiers grinding by making specific net energy grinding >0,1 kWh per kg of applied solids

c) drying of the suspension at a temperature of >80°C With homogeneous oxide mixture,

d) sintering the oxide mixture prior to the formation of phases at a temperature of at least 1200°C,

e) obtaining a suspension and grinding obtained in stage d) of the product of sintering when the use of intensifiers grinding by making energy density >0,1 kWh per kg of the product of sintering,

f) drying of the suspension.

Figure 1 schematically presents proposed according to the invention method.

According to the proposed method of zirconium oxide with a purity of at least 95%, preferably >99%, at least one of the oxides of metals from the group of scandium, yttrium, rare earth elements and/or mixtures thereof in the desired stoichiometric ratio receive aqueous suspension that contains at least 50 wt.% solid phase mixed oxide. The oxides of zirconium, used as starting material may contain up to 3 wt.% HfO₂.

To prevent agglomeration of the oxide particles and obtain a low viscosity and good transported suspension add dispersible auxiliary tool from a polyacrylate polymer, polyelectrolyte or polyacrylic acid. Good results are achieved, for example, in the application, per part of solids suspensions, from 1 to 12 wt.%, preferably from 3 to 8 wt.% dispersant Dolapix CE 64 and/or Dolapix SA company Zschimmer &Schwarz.

An important role in proposed according to the invention the method play morphological characteristics of primary substances of zirconium oxide. Found that the primary substance of zirconium oxide with lengths of edges (a, b, C) crystallite and=20-75 nm, b=20-90 nm and C=20-75 nm, preferably a=30-75 nm, b=30-75 nm and C=30-75 nm, particularly preferably and=35-50 nm, b=45-60 nm and C=35-45 nm lead to proposed according to the invention the powders.

In addition, it was found that the primary substance of zirconium oxide with a specific surface area (BET) of from 3 to 30 m²/g, preferably about the 6 to 15 m ²/g, particularly preferably from 6 to 11 m²/g, measured according to ASTM D of 3,663 lead to proposed according to the invention the oxides of zirconium.

Crucial to obtain oxides of zirconium according to the invention is intensive homogenization of the suspension by wet grinding. For carrying out processes of grinding, you can use different equipment. Suitable for this are various types of ball mills. Preferably, the grinding is carried out in ball mills with a stirrer. Now found that the wet grinding of the oxide mixture is carried out in a ball mill with agitator by making specific net energy of the grinding, after the introduction of energy or making energy milling (MEI), from 0.1 to 2.0 kWh / kg of applied solids for proposed according to the invention the powders with special properties.

Making energy net-grinding (E_net)is determined as the difference you make gross energy milling (E_grossand make energy at idle mills (E_idle). E_grossrecord using the built in mill performance counter/energy (D 122 firms Gönnheimer). E_idleis obtained as the product of power at idle (P_idle) mills and duration mill (t). As power idling speed mean power, the cat heaven needed a mill at the stated speed without filling the grinding bodies and suspension for operation. Power consumption of the mill can be considered directly by the performance counter/energy.

E_net=E_gross-E_idle(in kWh), and

E_idle=P_idle·t.

Making effective specific energy of grinding (MEI) is obtained as the ratio of E_netand applied mass of oxides (M).

The MEI=E_net/M_oxide(in kWh)

Preferably the introduction of effective specific energy of grinding is from 0.2 to 1.5 kWh/kg, preferably from 0.1 to 1.0 kWh/kg, preferably from 0.2 to 1.0 kWh/kg, preferably from 0.3 to 1.0 kWh/kg, particularly preferably from 0.2 to 0.7 kWh/kg, particularly preferably from 0.6 to 0.8 kWh/kg applied solids and, in particular, preferably from 0.2 to 0.5 kWh/kg applied solids.

After homogenization and subsequent drying at temperatures ≥80°C the oxide mixture is sintered at temperatures of at least 1200°C. Preferably the sintering is carried out at a temperature of 1200-1350°C., particularly preferably at temperatures 1250-1300°C.

The sintered powder is then subjected to intensive wet-milling, to get to the next processing good, dispersible until the field of primary particles, powders. The concentration of solids in suspension can be up to 80 wt.%, preferably up to 70 mA is.%, preferably, the concentration of solids in the suspension is from 40 to 70 wt.%, preferably from 60 to 70 wt.%, particularly preferably 50 to 60 wt.%.

Preferably wet grinding is carried out at introducing effective specific energy of grinding from 0.4 to 2.5 kWh/kg, particularly preferably from 0.7 to 1.9 kW/kg, particularly preferably from 0.4 to 1.0 kWh/kg, particularly preferably from 0.4 to 0.8 kWh/kg, and particularly preferably from 0.4 to 0.6 kWh/kg solids.

After grinding, the suspension is dried at temperatures ≥ 80°C. Preferably the drying is carried out in the spray dryer at temperatures ≥80°C, preferably ≥100°C, particularly preferably ≥110°C.

Received proposed according to the invention by way of new powder of zirconium oxide is particularly suitable for the production of substrates and, in particular, to obtain an electrolyte substrates for ceramic fuel cells.

Proposed according to the invention the powder of zirconium oxide can be molded to a particularly dense molded parts.

The object of the invention are also extruded parts, consisting of proposed according to the invention of zirconium oxides. Proposed according to the invention molded parts have a density of semi-finished product, which ranges from 54 to 65%, preferably from 56%to 62%, especially preferred is sustained fashion from 56% to 58% of theoretical density.

The density of the semi-finished molded parts can be installed by geometric methods. Moreover, the test sample area of 1 cm²and a height of 5-10 mm is pressed in one direction under the pressure of 100 MPa. Then the test sample zapressovyvajut isostatically under pressure to 2000 MPa, and then calculate its volume (V) according to the formula

V=a x b x C,

moreover, a, b, C denote the lengths of the sides of the test sample. The density of the semi-finished product is detected by dividing the mass of the test sample on the sample volume. Proposed according to the invention powdered oxides of zirconium also differ in their high activity sintering. Molded parts obtained from proposed according to the invention the oxides of zirconium, differ in that they are after sintering to form a gas-tight sintered body with high hardness.

The density of the sintered molded parts can be identified by the method of hydrostatic weighing. To do this, measure the mass of the specimen in air and in water at a temperature of 21°C and the density is determined according to the formula

The object of the invention are also sintered substrates for ceramic electrolyte fuel cells, consisting of proposed according to the invention the oxides of zirconium.

Proposed according to the invention is Pixies substrates are characterized by their high electrical conductivity, later also called SEL. The level of electrical conductivity depends on the type and concentration added to this component metal oxides and temperature. Thus, the substrates of proposed according to the invention of zirconium oxides with 3.5 mol.% Y₂O₃have SEL, at least 2.5 sec/m, preferably at least a 2.7 s/m, particularly preferably at least 2,9 s/m, measured at a temperature of 850°C. the Substrates of proposed according to the invention the oxides of zirconium with 4 mol.% Yb₂O₃have SEL, at least a 3.8 s/m, preferably at least 4.2 S/m Substrates with 6 mol.% Yb₂O₃have SEL, at least, 6,6 s/m, preferably at least 6,8/m

The specific conductivity can be determined using the method of measuring DC 4 points.

Of the powders through the casting of films get ceramic test specimen with a length of about 50 mm, a width of 10 mm and a thickness of about 100 μm. The slip casting of films produced by the fact that 250 grams of powder mixed with 202 g of commercially obtained binder, for example, (company Ferro, Binder B73208) when adding intensifiers grinding 418 g of grinding rollers 3YSZ (12 mm diameter) and 418 g of grinding rollers 3YSZ (10 mm diameter) company Tosoh in a plastic bottle with a volume of 1 liter. The slip casting films homogenized those who giving 48 hours on a series of rollers. Then grinding roller is separated and the slip Tegaserod within 24 hours by slow rotation in 0.5 l plastic bottle. The slip poured through the filter on a flat surface and using a squeegee applied at a height of about 250 microns. After drying for 7-24 hours of film is cut into strips which after sintering for 1 hour at a temperature of 1500°To get the above tested sample.

After measuring the height (H) and width (b) of the test sample using a micrometer with an accuracy of +/-1 μm, four contact strips not containing agglomerates platinum paste (firm Matek, Jülich) across the entire width of the test sample with a template applied to the test sample and calcined for 1 hour at a temperature of 1200°C. the Length of the inner contact strips (L) amounts to 25.5 mm External contact of the tape is located at a distance of 7 mm to the inner contact strips. Annealed platinum contacts of the sample with the body of aluminum oxide with a mass of 20 g stamp on platinum fixed contacts of the measuring holder. External contacts make the parallel (I) 150 µa while the voltage (U) is measured between the inner contacts using digital voltmeter.

To avoid polarization or contact effects on the internal electrodes vary the polarity and the height of the thread. zavisimosti conductivity polarization or contact effects on the internal electrodes provide by that change polarity and the height of the flow results in a negligible change polarity.

Specific conductivity (SEL) of the sample is calculated according to the formula

Proposed according to the invention the substrates are distinguished also by their high mechanical strength. Thus proposed according to the invention the substrates with 3.5 mol.% Y₂O₃show strength from 2000 to 2500 MPa. Substrates from 8.9 mol.% Y₂O₃show the strength of 900 to 1000 MPa. Substrates with 4 mol.% Yb₂O₃show strength from 2000 to 2100 MPa, with 6 mol.% Yb₂O₃from 1050 to 1150 MPa.

Mechanical strength can be set according to ring and ball, protected DIN 52292.

From dry green foil stamp circular samples with a diameter of about 34 mm and then is sintered for one hour at 1500°C. After sintering all samples have the radius (r₃) about 27 mm and a thickness (t) of about 100 μm. 20 pieces of the sintered samples sequentially in the location of the ring and ball by using a testing machine Instron company determine the force F required for cracking. The ring has a diameter (r₂) 5,6 mm Poisson's Ratio v assume 0,30. Test speed of 0.5 mm/min Cracking of the samples is determined using an ultrasonic measuring head. For the sake of the loaded surface (r ₁) assume approximately t/3. What happens when the cracking tensile stress calculated according to the following formula:

Of the 20 measured values statistics set according to Weibull. The strength referred to in the examples come from this standard statistical calculations. By the usual approximation of the diameter of the loaded area (r₁may be a systematic overestimation of the calculated stress at break. Therefore, the thickness of the samples result in the following examples. When equal to the thickness of the samples is possible the comparison of different materials samples.

Proposed according to the invention, the oxides of zirconium is used preferably for receiving electrolyte substrates /or functional layers in fuel cells. Therefore, an object of the invention is a fuel cell containing a substrate of proposed according to the invention of zirconium oxide. The object of the invention is the fuel cell, which has at least one functional layer, which contains at least one powder is proposed according to the invention of zirconium oxide. In the preferred embodiment proposed according to the invention a fuel cell is an anode or electrolyte fuel cell.

the alley invention in more detail, explain with examples.

Examples

In the following examples for the analysis used the following measurement methods:

- specific surface BET ASTM D of 3,663,

- the distribution of the total particle - Microtrac X100 With ASTM 1070 10 minutes prior sonification,

- the size of the crystallites - XRD line prole analysis

- monoclinic part of the phase - determination according Dirats / PWA-N 62

- bulk density - ASTM 417

Example 1

In water cooled double-walled receiving tank is placed a 10.74 liters of demineralized water and suspended with stirring, fast-moving agitator 23.5 kg Zr₂with a specific surface area 7,54 m²/g and the lengths of the faces of the crystallite and=47 nm, b=58 nm, C=43 nm and 1.56 kg Y₂O₃with a specific surface area are 5.36 m²/g, i.e., the solids content is 70 wt.%. To stabilize the suspension at the moment add 0,37 kg of a mixture 1:1 of both dispersant qualities Dolapix CE 64 and Dolapix SA company Zschimmer &Schwarz, as a result achieve greater electrokinetic potential. During grinding then continuously add the following amounts of dispersant mixture Dolapix CA/CE64, in addition to enough to stabilize the surface and charges, with newly formed progressive grinding, so that the suspension, despite the high concentration of solids in the grinding time, remains the low viscosity and is well mixed and extracted. The suspension is pumped through a membrane pump from the receiving tank through the coated polypropylene ball mill with agitator type LMK 4 company Netzsch Feinmahltechnik and then return to the receiving container, that is, the reduction takes place by the method of circulation. The grinding zone of the mill fill 10 kg of grinding balls with a diameter of 0.6 mm Zirconia (YSZ), yttrium-stabilized. The number of revolutions of the shaft of the agitator is 1950 min^-1.

Making energy net-grinding (E_net) is determined as the difference you make gross energy milling (E_grossand make energy at idle mills (E_idle). E_grossrecord using the built in mill performance counter/energy (D 122 firms Gönn-heimer). E_idleis obtained as the product of power at idle (P_idle) mills and duration mill (t).

E_net=E_gross-E_idle(in kWh), and

E_idle=P_idle·t.

Making effective specific energy of grinding (MEI) is obtained as the ratio of E_netand applied mass of oxides (M).

The MEI=E_net/M_oxide(in kWh)

The sample is crushed to make gross-energy milling of 30.6 kWh. Adopted by the resource path of the template with a given number of revolutions of the shaft of the agitator is 1950 min -11,30 kW and duration of 9 hours grinding. Thus, get the introduction of net-energy grinding 0,754 kWh/kg

After grinding, the suspension is dried by atomization. The initial temperature of spray drying is 300°C, the final temperature of 105°C. the Material spray drying discharged material and the cyclone-material are combined and passed through a pressure relief sieve of 250 μm. Dried spray powder has a specific surface area of 15.9 m²/year

Then gomogenizirovannogo mixture of primary substances is sintered in the vaulted oven type "NT 440" firm Nabertherm by blowing air at a temperature of 1300°C With a holding time of 2 hours, the heating rate and cooling respectively 5 K/min Product sintering again pulverized in a ball mill with agitator making specific net energy grinding of 0.75 kWh/kg and then dried by spraying. To destroy a coarse sintered agglomerates, at this time, the grinding is conducted with two-stage grinding balls YSZ, and at the first stage, the use of grinding balls with a diameter of 2 mm and in the second stage of grinding balls with a diameter of 0.6 mm Change of grinding balls is after making specific net energy grinding of 0.3 WH/kg, In opposition to the grinding of the primary substances in the grinding of the sintered products is enough Oder the basic add 1% dispersant, in the calculation of the applied solid.

The obtained powder of zirconium oxide has a specific surface 10,63 m²/g, the value of d₉₀of 0.71 μm and a bulk density of 1.81 g/cm³. The content of Y₂O₂is 3.5%. Monoclinic part of the phases is 41%vol.

The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.

Extruded body show the density of the semi-finished product 3,44 g/cm³. The density of the pressed bodies after sintering at 1500°C/1 h is 6,01 g/cm³(level 98.2% of theoretical density). The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates. The substrates sintered at a temperature of 850°C show specific conductivity 2,70/m Mechanical strength 90 μm thick substrates, calculated using ring and ball is 2413 MPa. The zirconium oxide in the sintered substrates almost completely stable, monoclinic part of the phases is <1%vol.

Example 2

23.5 kg ZrO₂with a specific surface area 9,71 m²/g and the lengths of the faces of the crystallite and=36 nm, b=46 nm, C=36 nm and 1.56 kg Y₂O₃with a specific surface area are 5.36 m²/g suspended 10.7 liters of water. P is ICEM solids content of the suspension is 70 wt.%. Gomogenizirovannogo mixture of primary substances shows after spray drying, the specific surface 19,28 m²/, Carrying out example is similar to example 1.

The obtained powder of zirconium oxide has a specific surface 9,43 m²/g, the value of d₉₀of 0.57 μm and a bulk density of 1.84 g/cm³. The content of Y₂O₃is 3.5 mol.%. Monoclinic part of the phases is 39%. The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.

Extruded body show the density of the semi-finished product to 3.49 g/cm³. The density of the pressed bodies after sintering at 1500°C/1 h is 6,01 g/cm³. The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates. The sintered substrates show at a temperature of 850°C specific conductivity (SEL) 2,72 With/m Mechanical strength 90 μm thick substrates is 1954 MPa. The zirconium oxide in the sintered substrates stabilized completely, i.e. monoclinic phase Zr₂no longer is confirmed through microinstructions analysis.

Example 3

66 kg ZrO₂with a specific surface area 6,63 m²/g and the lengths of the faces of the crystallite, a=50 nm, b=5 nm, C=44 nm, and 4.4 kg Y₂O₃with a specific surface area 3,74 m²/g suspended in 47 liters of water. Moreover, the solids content of the suspension is 60 wt.%. The grinding of the primary substances spend in making effective specific energy of grinding 0,50 kWh/kg solids. Gomogenizirovannogo mixture of primary substances shows after spray drying specific surface area of 14 m²/, Following the holding of the example is similar to example 1.

The product obtained has a specific surface or 10.60 m²/g, the value of d₉₀of 0.64 μm and a bulk density of 1,72 g/cm³. The content of Y₂O₃is 3.5 mol.%. Monoclinic part of the phase is 50%. The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.

Extruded body show the density of the semi-finished product of 3.46 g/cm³. The density after sintering at 1500°C/1 h is 6,01 g/cm³. The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates. The sintered substrates show at a temperature of 850°C specific conductivity (SEL) 2,73 With/m Mechanical strength 90 μm thick substrates is 2390 MPa. Oxide C is rcone in the sintered substrates stabilized completely, that is, the monoclinic phase of ZrO₂no longer is confirmed through microinstructions analysis.

Example 4

93,7 kg ZrO₂with a specific surface area 6,63 m²/g and the lengths of the faces of the crystallite, a=50 nm, b=59 nm, C=44 nm and 6.2 kg Y₂O₃with a specific surface area 3,74 m²/g suspended in 66,6 liters of water. Moreover, the solids content of the suspension is 60 wt.%. Conduction takes place analogously to example 1.

The product obtained has a specific surface area of 11 m²/g, the value of d₉₀of 1.16 μm and bulk density 1,67 g/cm³. The content of Y₂O₃is 3.5 mol.%. Monoclinic part of the phases is 60 vol.%. The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.

Extruded body show the density of the semi-finished product to 3.35 g/cm³. The density after sintering at 1500°C/1 h is 6,09 g/cm³. The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates. The sintered substrates show (SEL), measured at a temperature of 850°C, And 2.83/m Mechanical strength 90 μm thick substrates is 2191 MPa. The zirconium oxide in the sintered substrates stabilized completely,i.e. monoclinic phase of ZrO ₂no longer is confirmed through microinstructions analysis.

Example 5

46,5 kg ZrO₂with a specific surface area to 7.67 m²/g and the lengths of the faces of the crystallite and=47 nm, b=56 nm, C=43 nm and 3.2 kg Y₂O₃with a specific surface area of 7 m²/g suspended in a 33.2 liters of water. Moreover, the solids content of the suspension is 60 wt.%. Conduction takes place analogously to example 1.

The resulting powder has a specific surface 11,48 m²/g, the value of d₉₀of 0.7 μm and a bulk density 1,71 g/cm³. The content of Y₂O₃is 3.5 mol.%. Monoclinic part of phase powder is 45%. The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.

Extruded body show the density of the semi-finished product 3,55 g/cm³. The density after sintering at 1500°C/1 h is of 6.02 g/cm³. The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates. The sintered substrates show (SEL), measured at a temperature of 850°C, 2,87 With/m Mechanical strength 90 μm thick substrates is 2285 MPa. The zirconium oxide in the sintered substrates stabilized completely, i.e. monoclinic f is for ZrO ₂no longer is confirmed through microinstructions analysis.

Example 6

According to the process described in example 1, receive alloyed powder ZrO₂with different contents of Y₂O₃. Apply zirconium oxide with a specific surface area to 7.67 m²/g and the lengths of the faces of the crystallite and=47 nm, b=56 nm, C=43 nm, as well as used in example 5, Y₂O₃with a specific surface area of 7 m²/, Properties of the obtained powder, pressed bodies and substrates take in table 1. In table 1, it should be seen that with increasing content of yttrium oxide increases the specific conductivity. In figure 2 represent the mechanical strength and the specific conductivity of the substrates obtained from proposed according to the invention of zirconium oxides in examples 1-6, depending on the content of Y₂O₃.

Example 7

The method described respectively in example 1 to produce a powder ZrO₂doped with 4 mol.% Y₂O₃. And apply 22,1 kg ZrO₂used in example 1, and zirconium oxide with a specific surface area to 7.67 m²/g and 2.9 kg Y₂O₃with a specific surface area of 3.77 m²/g 10.7 liters of water. Moreover, the solids content of the suspension is 70 wt.%.

The product obtained has a specific surface 10,89 m^{2 /g, the value of d₉₀of 0.79 μm and a bulk density of 1.73 g/cm3. Monoclinic part of phase powder is 30 vol.%. The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.}

Extruded body show the density of the semi-finished product 3,66 g/cm³. The density after sintering at 1500°C/1 h is 6,32 g/cm³. The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates.

As shown in figure 3, the sintered substrates of ZrO₂doped with ytterbium oxide, (YbSZ) at a temperature of 850°C shows the specific conductivity is 4.21 s/m, which is thus clearly higher than in the comparable substrates of ZrO₂doped with 4 mol.% Y₂O₃.

(YSZ), example 6. The mechanical strength of 95 μm thick substrates is 2066 MPa. The zirconium oxide in the sintered substrates stabilized completely, i.e. monoclinic phase of ZrO₂no longer is confirmed through microinstructions analysis.

Example 8

Accordingly, example 7 to produce a powder ZrO₂alloyed 6 mol.% Y₂O₃based on 20,8 kg ZrO₂and 4.2 kg Y₂O₃.

The resulting product is specific for Ernest 9,07 m ²/g, the value of d₉₀of 0.77 μm and a bulk density of 1.84 g/cm³. Monoclinic part of phase powder is 13%. The powder is pressed under uniaxial pressure of 100 MPa to obtain a molded phone Then the samples isostatically zapressovyvajut under pressure to 2000 MPa.

Extruded body show the density of the semi-finished product 3,74 g/cm³. The density after sintering at 1500°C/1 h is 6,492 g/cm³. The powder may very well be processed by casting films, drying and one-hour sintering at 1500°C to obtain electrolyte substrates.

As shown in figure 3, the sintered substrates (6YbSZ) at a temperature of 850°C shows the specific conductivity 6,85 s/m, which is thus clearly higher than in the comparable substrates of ZrO₂doped with 6 mol.%. Y₂O₃from example 6. The mechanical strength of 95 μm thick substrate 1108 is MPa. The zirconium oxide in the sintered substrates stabilized completely, i.e. monoclinic phase of ZrO₂no longer is confirmed through microinstructions analysis.

1. Powdered zirconium oxide containing up to 10 mol.%, at least one metal oxide from the group of scandium, yttrium, rare earth elements and/or mixtures thereof, which has a filling density of from 1.2 to 2.5 g/cm³, measured according to the but In ASTM 417.

2. Powdered zirconium oxide according to claim 1, characterized in that it has a filling density from 1.3 to 1.9 g/cm³.

3. Powdered zirconium oxide according to claim 1, characterized in that it contains from 3 to 10 mol.% Y₂O₃.

4. Powdered zirconium oxide according to claim 1, characterized in that it contains from 3 to 6 mol.% Y₂O₃.

5. Powdered zirconium oxide according to claim 1, characterized in that it contains 3 to 4% mol.% Y₂O₃.

6. Powdered zirconium oxide according to claim 1, characterized in that it contains from 3 to 10 mol.% Yb₂O₃.

7. Powdered zirconium oxide according to claim 1, characterized in that it contains from 3 to 7 mol.% Yb₂O₃.

8. Powdered zirconium oxide according to claim 1, characterized in that it has a specific BET surface of from 5 to 18 m²/g, measured according to ASTM D of 3,663.

9. Powdered zirconium oxide according to claim 1, characterized in that it has a specific BET surface of 10 to 16 m²/g, measured according to ASTM D of 3,663.

10. Powdered zirconium oxide according to one of claims 1 to 9, characterized in that it has from 5 to 80 vol.% monoclinic parts of the phase.

11. Powdered zirconium oxide according to one of claims 1 to 9, characterized in that it has from 20 to 80 vol.% monoclinic parts of the phase.

12. Powdered zirconium oxide according to one of claims 1 to 9, characterized in that it has from 45 to 70 vol.% monocline the s parts of the phase.

13. The method of obtaining of zirconium oxides, doped metal oxides from the group of scandium, yttrium and rare earth elements and/or mixtures thereof, comprising the following stages:
a) preparation of an aqueous suspension of zirconium oxide and the corresponding metal oxide in stoichiometric ratio, including stabilizing the suspension by means of a disperser;
b) homogenization of the suspension by grinding with the use of intensifiers grinding by making specific net energy grinding >0,1 kWh per kg of applied solids,
c) drying of the suspension at a temperature ≥80°C To produce a homogeneous oxide mixture,
d) sintering the oxide mixture at temperatures of at least 1200°C,
e) obtaining a suspension and grinding obtained at the stage
d) the product of sintering by making energy density >0,1 kWh per kg of the product of sintering,
f) drying of the suspension.

14. The method according to item 13, wherein the lengths of the edges (a, b, C) crystallite used raw materials of zirconium oxide have values a=20-75 nm, b=20-90 nm and C=20-75 nm.

15. The method according to item 13, wherein the lengths of the edges (a, b, C) crystallite used raw materials of zirconium oxide have values a=30-50 nm, b=45-60 nm and C=35-45 nm.

16. The method according to item 13, wherein the used raw materials of zirconium oxide have a specific surface area of ET from 3 to 30 m ²/g, measured according to ASTM D of 3,663.

17. The method according to item 13, wherein the used raw materials of zirconium oxide have a BET specific surface ranging from 6 to 11 m²/g, measured according to ASTM D of 3,663.

18. The method according to item 13, wherein the homogenization of the starting materials is carried out by wet grinding when making specific net energy grinding from 0.2 to 1.5 kWh/kg solids.

19. The method according to item 13, wherein the homogenization of the starting materials is carried out by wet grinding when making specific net energy grinding from 0.3 to 1.0 kWh/kg solids.

20. The method according to item 13, wherein the homogenization of the starting materials is carried out by wet grinding when making specific net energy grinding from 0.6 to 0.8 kWh/kg solids.

21. The method according to item 13, wherein the suspension is spray dried.

22. The method according to item 13, wherein the sintering is carried out at temperatures from 1200 to 1350°C.

23. The method according to item 13, wherein the sintering is carried out at temperatures from 1250 to 1300°C.

24. The method according to item 13, wherein the wet grinding the sintered oxide of the mixture is carried out at introducing specific net power grinding 0,5-2,5 kWh/kg of oxide mixture.

25. The method according to item 13, wherein the wet grinding the sintered oxide of the mixture is carried out at introducing specific net power at the Ola 0,7-1,9 kWh/kg of oxide mixture.

26. Extruded body comprising a powder of zirconium oxide on one or more of claims 1 to 12.

27. Extruded body p, which has a density of prefabricated from 54 to 65% of theoretical density sintering.

28. Extruded body p, which has a density of prefabricated from 56 to 62% of theoretical density sintering.

29. Extruded body p, which has a density of prefabricated from 56 to 58% of theoretical density sintering.

30. The substrate for electrolytic ceramic fuel cells consisting of a powder of zirconium oxide on one or more of claims 1 to 12.

31. The substrate according to item 30, which has a specific electrical conductivity (SEL)of at least 2.5 sec/m, measured at a temperature of 850°C.

32. The substrate according to item 30, which has a specific electrical conductivity (SEL)at least a 3.8 s/m, measured at a temperature of 850°C.

33. The substrate according to item 30, which has a specific electrical conductivity (SEL)at least 6,6 s/m, measured at a temperature of 850°C.

34. The use of zirconium oxides according to one of claims 1 to 12 for receiving electrolyte substrates and/or functional layers in fuel cells.

35. Fuel cell containing substrate according to item 30.

36. Fuel cell, which has at least one functional layer which contains an oxide of zirconium, one or some of the above items.

37. Fuel cells for p or 36, which are anode or electrolyte cell.