阅读说明：本技术 一种钇稳定氧化锆及其生产工艺 (Yttrium stabilized zirconia and production process thereof ) 是由 王洋 于 2020-07-25 设计创作，主要内容包括：本申请公开了一种钇稳定氧化锆及其生产工艺,属于氧化锆材料技术领域。本申请的钇稳定氧化锆的生产工艺,包括如下步骤：1)将制备原料混合均匀,在2600-2800℃下保温1-3h,制得熔融液；所述制备原料包括如下重量份数的组分：氧化锆88-92份、氧化钇8-10份、氧化钙0.8-1.5份、氧化镁0.2-0.3份；2)将步骤1)得到的熔融液采用压缩气体进行喷吹,将喷吹出的颗粒冷却。本申请的钇稳定氧化锆生产工艺采用了非常高的烧结温度,能够制得致密度高且晶相分布均匀的氧化锆材料,材料具有高稳定性,颗粒表面不易出现裂纹。(The application discloses yttrium-stabilized zirconia and a production process thereof, belonging to the technical field of zirconia materials. The production process of the yttrium-stabilized zirconia comprises the following steps: 1) uniformly mixing the preparation raw materials, and preserving heat for 1-3h at the temperature of 2600-; the preparation raw materials comprise the following components in parts by weight: 88-92 parts of zirconium oxide, 8-10 parts of yttrium oxide, 0.8-1.5 parts of calcium oxide and 0.2-0.3 part of magnesium oxide; 2) blowing the molten liquid obtained in the step 1) by using compressed gas, and cooling the blown particles. The production process of the yttrium-stabilized zirconia adopts very high sintering temperature, can prepare the zirconia material with high density and uniform crystal phase distribution, has high stability, and is not easy to crack on the surface of particles.)

1. A production process of yttrium-stabilized zirconia is characterized by comprising the following steps: the method comprises the following steps:

1) uniformly mixing the preparation raw materials, and preserving heat for 1-3h at the temperature of 2600-; the preparation raw materials comprise the following components in parts by weight: 88-92 parts of zirconium oxide, 8-10 parts of yttrium oxide, 0.8-1.5 parts of calcium oxide and 0.2-0.3 part of magnesium oxide;

2) blowing the molten liquid obtained in the step 1) by using compressed gas, and cooling the blown particles.

2. Process for the production of yttrium-stabilized zirconia according to claim 1, characterized in that: the preparation raw materials also comprise 0.3-0.5 weight part of alumina and 0.5-0.8 weight part of cosolvent.

3. Process for the production of yttrium-stabilized zirconia according to claim 1, characterized in that: the preparation raw material also comprises 0.1-0.2 weight part of bismuth oxide.

4. Process for the production of yttrium-stabilized zirconia according to claim 1, characterized in that: the step 1) of uniformly mixing the preparation raw materials is ball milling for 3-10h at the rotating speed of 300-1800 rpm.

5. Process for the production of yttrium-stabilized zirconia according to claim 1, characterized in that: the preparation raw material also comprises a carbon material; the carbon material is at least one of activated carbon, graphite, Ketjen black and graphene.

6. Process for the production of yttrium-stabilized zirconia according to claim 5, characterized in that: the mass ratio of the carbon material to the zirconia is 0.5-1: 88-92.

7. Process for the production of yttrium-stabilized zirconia according to claim 5, characterized in that: the carbon material is formed by mixing at least one of activated carbon, graphite and graphene with Ketjen black in a mass ratio of 3-5: 1.

8. Process for the production of yttrium-stabilized zirconia according to any one of claims 1 to 7, characterized in that: and 2) cooling to obtain hollow spheres, soaking the hollow spheres in a zirconium salt solution for 2-3h, and sintering at the temperature of 1500-.

9. Process for the production of yttrium-stabilized zirconia according to claim 8, characterized in that: the zirconium salt in the zirconium salt solution is at least one of zirconium acetate, zirconium oxalate and zirconium nitrate.

10. An yttrium-stabilized zirconia produced by the process of claim 1, wherein: the yttrium-stabilized zirconia is spherical or near-spherical particles comprising spherical shells that enclose an internal cavity.

Technical Field

The application relates to the technical field of zirconia materials, in particular to yttrium-stabilized zirconia and a production process thereof.

Background

The zirconia material has the characteristics of high melting point, high resistivity, high refractive index and low thermal expansion coefficient, and has wide application in the industrial fields of structural ceramics, electronic ceramics, biological ceramics, optical fiber communication, sensors, fuel cells and the like.

The stabilized zirconia has three crystal forms and belongs to a polycrystal phase inversion product. The stable low temperature phase is monoclinic phase, tetragonal phase is gradually formed above 1000 deg.C, and is transformed into cubic phase above 2370 deg.C. Because the monoclinic phase generates larger volume change when being transformed to the tetragonal phase, and the monoclinic phase generates larger volume change in the opposite direction when being cooled, the cracking of the material is easily caused. Therefore, in actual use, in order to fully utilize the advantages of zirconia, zirconia composite materials are mostly adopted to improve the stability of zirconia and replace pure zirconia materials.

Among zirconia composite materials, ceramic materials with a high zirconia proportion have high corrosion resistance and high thermal stability, and are commonly used as refractory materials in special fields. The microstructure of the zirconia composite material is composed of a large amount of zirconia grains and a small amount of matrix glass filled among the grains, so that the zirconia composite material has excellent mechanical properties. During the high-temperature sintering, if the sintering temperature is not high enough, the zirconia in the material has the transformation between a monoclinic phase and a tetragonal phase, and phase change stress is generated in the material, so that the material is unstable. In the later use process, the material is easy to crack due to temperature change, and further the heat resistance and the electrical performance of the material are rapidly reduced.

In order to improve the stability of the zirconia material, in the actual production process, yttrium is introduced into the zirconia in a more adopted way. The yttrium is introduced by a mechanical mixing method, a precipitation method, a sintering method, or the like. Among them, the mechanical mixing method is generally to mix zirconia with yttria, wet-grind it, and then spray-dry it. The method is difficult to produce the zirconia composite material in the true sense, and the prepared material has a large amount of monoclinic phase zirconia, so that the stability of the material is not substantially improved. The precipitation method is to carry out precipitation reaction in solution, and the prepared material has higher uniformity than the material prepared by a mechanical mixing method, but the monoclinic problem of the material cannot be fundamentally solved. The sintering method generally adopts a binder to bond and press the zirconia and the yttria and then sintering, but in order to grind the prepared zirconia material to be finer, the sintering temperature is generally not more than 1800 ℃.

The Chinese patent application with the application publication number of CN103992109A discloses a preparation method of a zirconia and yttria mixture ceramic target, which comprises the following steps in sequence: (1) will be provided withZrO of greater than 99.9% purity₂Particles and Y₂O₃The particle mixture adopts ZrO₂Ball milling and mixing the ZrO through grinding balls₂The mass fraction of the particles in the mixture is 92-94%, and the Y content is₂O₃The mass fraction of the particles in the mixture is 6-8%, and the particle size of the mixed powder after ball milling and mixing is 10-100 nm; (2) carrying out cold isostatic pressing on the mixed powder to obtain a blank of the mixture ceramic target material, wherein the volume density of the blank is 3.8-4.1g/cm³(ii) a (3) Sintering the blank at high temperature to obtain a biscuit of the mixture ceramic target material; (4) the biscuit is mechanically processed to obtain the biscuit with the volume density of 5.2-5.4g/cm³The mixture ceramic target of (1). The sintering temperature of the high-temperature sintering is 1400-1650 ℃, and the high-temperature heat preservation time is 1-4 h. In the preparation method, the blank is prepared by adopting cold isostatic pressing, so that the density of the prepared ceramic material is improved, and the introduction of impurities is reduced. However, the sintering temperature in the preparation method is still low, and the stability of the prepared zirconia ceramic material still needs to be improved.

Disclosure of Invention

In view of the defects in the prior art, the first objective of the present application is to provide a production process of yttrium-stabilized zirconia, which has high sintering temperature and higher stability of the obtained zirconia material.

A second object of the present application is to provide a yttrium-stabilized zirconia obtained by the above method.

In order to achieve the first object, the present application provides the following technical solutions:

a production process of yttrium-stabilized zirconia comprises the following steps:

1) uniformly mixing the preparation raw materials, and preserving heat for 1-3h at the temperature of 2600-; the preparation raw materials comprise the following components in parts by weight: 88-92 parts of zirconium oxide, 8-10 parts of yttrium oxide, 0.8-1.5 parts of calcium oxide and 0.2-0.3 part of magnesium oxide;

2) blowing the molten liquid obtained in the step 1) by using compressed gas, and cooling the blown particles.

By adopting the technical scheme, the spherical zirconia composite material can be prepared by adopting the preparation raw materials containing zirconia and yttria, preparing oxide into molten liquid at a very high temperature and then adopting a compressed gas blowing mode. In the high-temperature molten state, the various oxides are sufficiently fused to form a very stable phase. The sprayed particles are cooled to obtain a material with uniform phases, so that the stability of the material is greatly improved. Besides the yttrium oxide, the calcium oxide and the magnesium oxide are added into the preparation raw materials, and the calcium oxide and the magnesium oxide play a role in stabilizing the zirconium oxide together. The magnesium oxide can also improve the bonding strength of particles in the material, further improve the overall stability of the material, and the prepared zirconia material is not easy to crack on the surface when being subjected to external force or extreme environment.

The application is further configured to: the preparation raw materials also comprise 0.3-0.5 weight part of alumina and 0.5-0.8 weight part of cosolvent.

By adopting the technical scheme, the alumina is also added into the preparation raw materials, has very high hardness, and can improve the strength and toughness of the finally prepared composite material. In addition, during the high-temperature sintering process, solid solution can be formed by alumina and zirconia, and with the increase of temperature, a unique structure that zirconium crystal grains are attached to the surfaces of the aluminum crystal grains can be formed, so that the stability of the zirconium crystal phase is improved. Because more high-melting point oxides are added into the preparation raw materials, the melting of the oxides can be accelerated after the cosolvent is added, so that the raw materials are contacted more fully.

The application is further configured to: the preparation raw material also comprises 0.1-0.2 weight part of bismuth oxide.

By adopting the technical scheme, the stress concentration in the material can be reduced by adding the bismuth oxide, the stability of the finally prepared material is improved, and the probability of cracks on the surface of the material particles is reduced. However, if the bismuth oxide is added too much, the color of the prepared material is likely to change, and 0.1-0.2 part by weight of the bismuth oxide can ensure that the bismuth oxide can fully exert the stabilization promoting effect and avoid the influence on the color of the material.

The application is further configured to: the step 1) of uniformly mixing the preparation raw materials is ball milling for 3-10h at the rotating speed of 300-1800 rpm.

Through adopting above-mentioned technical scheme, because the raw materials kind of this application is more, if only adopt simple mixture then difficult intensive mixing between each raw materials even, this application is longer with the raw materials ball-milling for each raw materials can fully contact, mixes more evenly. Moreover, the particle size of the raw material particles formed after ball milling is smaller, which is beneficial to the rapid melting of the raw material when the temperature is raised, and the sintering time is shortened.

The application is further configured to: the preparation raw material also comprises a carbon material; the carbon material is at least one of activated carbon, graphite, Ketjen black and graphene.

By adopting the technical scheme, the carbon material can reduce oxide agglomeration when the raw materials are mixed, and in the high-temperature sintering process, the gasification of the carbon material can drive the original gas in the raw materials to diffuse through a crystal boundary, so that the pores in the material are fewer and finer, and the density of the finally prepared material is further improved.

The application is further configured to: the mass ratio of the carbon material to the zirconia is 0.5-1: 88-92.

By adopting the technical scheme, mass transfer among the zirconia grains can be blocked in the sintering process due to too much amount of the carbon material, and the growth of the grains can be prevented in the carbon oxidation process, so that the proportion of controlling the carbon material and the zirconia is lower in the application, and the size of the grains in the generated material can be conveniently controlled.

The application is further configured to: the carbon material is formed by mixing at least one of activated carbon, graphite and graphene with Ketjen black in a mass ratio of 3-5: 1.

By adopting the technical scheme, the adding amount of the carbon material is very small, and the key point for the function of the carbon material is how to disperse the carbon material in the raw material uniformly. The carbon material is formed by mixing the Ketjen black and other carbon materials, and can be well combined with other carbon materials by utilizing the branched chain structure of the Ketjen black, so that the dispersion uniformity of the carbon material in the raw material is improved.

The application is further configured to: and 2) cooling to obtain hollow spheres, soaking the hollow spheres in a zirconium salt solution for 2-3h, and sintering at the temperature of 1500-.

By adopting the technical scheme, the ceramic hollow sphere is soaked in a zirconium salt solution and then sintered, so that zirconium salt can be decomposed and a coating layer is formed on the surface of the ceramic hollow sphere, the mechanical property of the hollow sphere is enhanced, the hollow sphere can be protected, and the probability of cracks on the surface of the hollow sphere in the using process is reduced.

The application is further configured to: the zirconium salt in the zirconium salt solution is at least one of zirconium acetate, zirconium oxalate and zirconium nitrate.

By adopting the technical scheme, the zirconium salt is easily decomposed at high temperature, and is decomposed at high temperature to generate zirconium oxide, so that a zirconium oxide coating layer is generated on the surface of the ceramic hollow ball. Because the zirconium salt is attached to the surface of the ceramic hollow sphere in a solution form, the adsorption capacity of the solution is low, so that the generated zirconium oxide coating layer is very thin, and the mechanical property of the internal ceramic hollow sphere cannot be greatly influenced.

In order to achieve the second object, the present application provides the following technical solutions:

the yttrium-stabilized zirconia prepared by the production process is spherical or approximately spherical particles, and the spherical or approximately spherical particles comprise spherical shells, and the spherical shells surround an inner cavity.

By adopting the technical scheme, the yttrium-stabilized zirconia prepared by the production process is a zirconia composite material, oxides such as yttrium oxide and the like are added into the raw materials, so that the stability of the zirconia composite material is greatly improved, and the zirconia composite material prepared by the production process has a hollow spherical structure, so that the density of the zirconia composite material is greatly reduced, and the zirconia composite material has outstanding advantages in application.

In summary, the present application has the following beneficial effects:

1. the production process of the yttrium-stabilized zirconia adopts very high sintering temperature, greatly improves the melting and mixing uniformity of each oxide raw material, can prepare the zirconia material with high density and uniform crystal phase distribution, has high stability, and is not easy to crack the surface of material particles.

2. In the yttrium-stabilized zirconia production process, the hollow ball is soaked in a zirconium salt solution after being prepared, an even liquid film is attached to the surface of the ceramic hollow ball, and then the zirconium salt is decomposed to generate an oxide coating layer through sintering, so that the ceramic hollow ball can be well protected.

Drawings

FIG. 1 is a topographical view of yttrium-stabilized zirconia produced in example 2 of the present application.

Detailed Description

The technical solution of the present application is further described in detail below.

The production process of the yttrium-stabilized zirconia comprises the following steps:

1) uniformly mixing the preparation raw materials, and preserving heat for 1-3h at the temperature of 2600-; the preparation raw materials comprise the following components in parts by weight: 88-92 parts of zirconium oxide, 8-10 parts of yttrium oxide, 0.8-1.5 parts of calcium oxide and 0.2-0.3 part of magnesium oxide;

2) blowing the molten liquid obtained in the step 1) by using compressed gas, and cooling the blown particles.

The zirconia in the step 1) is fused zirconia. In the fused zirconia, ZrO₂Not less than 99.5% by mass, Fe₂O₃Is not more than 0.01 percent, TiO₂Is not more than 0.005% by mass, SiO₂Is not more than 0.01 percent. Preferably, the fused zirconia is fused zirconia produced by Shandong hong Yuan New Material science and technology Limited.

The preparation raw materials also comprise 0.2 to 0.3 weight part of alumina and 0.3 to 0.5 weight part of cosolvent. Preferably, 0.25 weight parts of alumina and 0.4 weight parts of cosolvent are included. Preferably, the average particle size of the alumina is 1 to 1.5 μm. More preferably, the average particle size of the alumina is 1 μm. The alumina is alpha alumina. Particle size of calcium oxide powder325 mesh, purity 85-98%. Preferably, the purity of the calcium oxide is 95%. The purity of the magnesium oxide is 95-98%. Preferably, the magnesium oxide is 98% pure. The bulk density of the magnesium oxide was 0.4g/cm³. The cosolvent is silicon dioxide or potassium chloride.

The step 1) of uniformly mixing the preparation raw materials is ball milling for 3-10h at the rotating speed of 300-1800 rpm. The ball milling adopts chemical zirconia ceramic balls.

Step 1), adding a carbon material when uniformly mixing the preparation raw materials; the carbon material is at least one of activated carbon, graphite, Ketjen black and graphene. The mass ratio of the carbon material to the electrically-fused zirconia is 0.5-1: 88-92. Further preferably, the carbon material is formed by mixing at least one of activated carbon, graphite and graphene with ketjen black in a mass ratio of 3-5: 1.

In the step 1), water is also added when the preparation raw materials are uniformly mixed. The mass ratio of the water to the electric melting zirconia is 2.5-5: 88-92.

In the step 1), the temperature is raised to 1600-.

The fused zirconia is dried, crushed and sieved before mixing. The drying is carried out at 40-50 ℃ for 30-50 min. The crushing is performed by ball milling at the rotating speed of 300-400rpm for 10-20 min. The screening is 400-2500 mesh screening. Preferably, the sieving is 400-800 mesh. Preferably, the screening is to pass through a 400-DEG C900-mesh sieve, then pass the undersize through a 1100-DEG C1600-mesh sieve, and take the oversize; or firstly screening the mixture through 900-1600-mesh sieve, then screening the undersize product through 1800-2500-mesh sieve, and taking the oversize product.

Further preferably, the screening is followed by electromagnetic iron removal. The magnetic flux density in the case of removing iron by electromagnetic induction was 1.5T, and the exciting current was 14A. The electromagnetic iron removal adopts a QM250 type electromagnetic iron remover, and is produced by ceramic equipment Limited of Hangshan.

In the step 2), the blowing is to blow the molten liquid into the air by adopting compressed gas. The compressed gas is any one of compressed air, compressed nitrogen and compressed argon. In the process of falling of the blown particles in the airAnd rapidly cooling to obtain hollow spherical particles, namely the ceramic hollow spheres. The pressure of the compressed air adopted during blowing is 7-9kg/cm². Further, the blown particles are cooled by nitrogen at 50-70 ℃.

The ceramic hollow spheres obtained after cooling in the step 2) are placed in a zirconium salt solution for soaking for 2-3h, and then sintered for 2-3h at the temperature of 1500-. More preferably, after soaking, drying at 45-55 deg.C for 15-20 min. Sintering at 1500-1700 ℃ for 2-3h, and cooling to room temperature. The cooling may be air cooling.

The ratio of said zirconium salt to the solvent in the solution of zirconium salt is between 0.8 and 1L of solvent per 25 and 35g of zirconium salt. Preferably, the zirconium salt solution is obtained by uniformly mixing a zirconium salt, a dispersing agent and a solvent. The zirconium salt is at least one of zirconium acetate, zirconium oxalate and zirconium nitrate. The dispersant is any one of polyethylene glycol, triethanolamine and hexadecyl trimethyl ammonium bromide. The solvent is water or ethanol or an ethanol water solution. The ethanol water solution is formed by mixing ethanol and water according to the volume ratio of 1: 3-5. Preferably, the mass ratio of the ethanol to the zirconium salt to the dispersant is 25-35: 5-10.