CN108439978A - A kind of yttria-stabilized zirconia powder and preparation method thereof and ceramics - Google Patents

Abstract

The invention belongs to technical field of powdered material preparation, a kind of yttria-stabilized zirconia powder and preparation method thereof and ceramics are specifically provided.The present invention coats yttrium oxide powder using cationic surfactant, coats Zirconium powder using anion surfactant, then act on by electrostatic attraction, obtains the powder that yttrium oxide uniformly coats zirconium oxide.The ceramics being prepared using the present invention, relative density are 98.7~99.5%；Hardness reaches 1352~1432HV, and fracture toughness reaches 4.47~4.82MPam^1/2。

Description

A kind of yttrium oxide stabilized zirconia powder and its preparation method and ceramics

technical field

The invention belongs to the technical field of powder material preparation, and in particular relates to a yttria-stabilized zirconia powder, a preparation method thereof and ceramics.

Background technique

Zirconia has high strength, high hardness and good biocompatibility, and can be used to make biological materials such as dentistry and human bones, and can also be used to make ceramic composite materials with fine structures. However, pure zirconia is prone to aging and cracking when exposed to water vapor. Therefore, in the prior art, yttrium oxide is often added to zirconia as a stabilizer to prepare yttrium oxide-stabilized zirconia powder. At present, the methods for industrially preparing yttria-stabilized zirconia powder include mechanical mixing method and co-precipitation method, among which mechanical mixing method is the more commonly used one. The mechanical mixing method is a preparation method of directly mixing yttrium oxide and zirconia powder, and distributing yttrium oxide on the surface of zirconia through ball milling, thereby obtaining yttria-stabilized zirconia powder.

Although the mechanical mixing method disclosed in the prior art can obtain yttria-stabilized zirconia powder, the yttrium oxide of the obtained powder cannot be evenly coated on the surface of zirconia, resulting in secondary recrystallization or local coarsening during the sintering process. It directly affects the phase formation and mechanical properties of zirconia ceramic products.

Contents of the invention

The purpose of the present invention is to provide a preparation method of yttria-stabilized zirconia powder. The preparation method provided by the present invention can obtain zirconia powder whose surface is evenly coated with yttria layer, and use the obtained yttria-stabilized zirconia powder to prepare The obtained ceramics have high hardness and toughness.

To achieve the above object, the invention provides a method for preparing yttria-stabilized zirconia powder, comprising the steps of:

A preparation method of yttrium oxide stabilized zirconia powder, comprising the steps of:

(1) disperse the yttrium oxide powder and the cationic surfactant into deionized water to obtain the yttrium oxide dispersion;

Dispersing the zirconia powder and anionic surfactant into deionized water to obtain a zirconia dispersion;

The particle size ratio of the yttrium oxide powder to the zirconia powder is 1:5 to 20;

(2) Under alternating electric field and stirring conditions, the yttrium oxide dispersion liquid obtained in the step (1) is mixed with the zirconia dispersion liquid, and coated to obtain a slurry of yttria-coated zirconia; the slurry The mass ratio of yttrium oxide to zirconium oxide is 1:4～20;

(3) Drying and pulverizing the slurry obtained in the step (2) in sequence to obtain yttria-stabilized zirconia powder.

Preferably, in the step (1), the mass ratio of the yttrium oxide powder to the cationic surfactant is 1:0.003-0.005, the solid content of the yttrium oxide dispersion is 20-30%, and the solid content is Yttrium oxide accounts for the mass percent of the yttrium oxide dispersion total amount;

The mass ratio of zirconia powder to anionic surfactant is 1:0.003-0.005, the solid content of the zirconia dispersion is 20-30%, and the solid content is the mass of zirconia in the total amount of zirconia dispersion percentage meter.

Preferably, the particle size of the yttrium oxide powder in the step (1) is 40-60 nm.

Preferably, in the step (1), the cationic surfactant includes cetylpyridinium chloride or cetyltrimethylammonium bromide; the anionic surfactant includes sodium deoxycholate or polymethacrylic acid .

Preferably, the preparation method of yttrium oxide dispersion in described step (1) comprises:

dissolving the cationic surfactant in partially deionized water to obtain a deionized aqueous solution of the cationic surfactant;

After mixing the deionized aqueous solution of the cationic surfactant, the yttrium oxide powder and the remaining deionized water, ball milling to obtain the yttrium oxide dispersion.

Preferably, the preparation method of the zirconia dispersion in the step (1) includes: mixing the zirconia powder, anionic surfactant and deionized water, and then ball milling to obtain the zirconia dispersion.

Preferably, the mixing method of the yttrium oxide dispersion liquid and the zirconium oxide dispersion liquid in the step (2) is dropwise addition, and the speed of the dropwise addition is 0.8-2 mL/s.

Preferably, the frequency of the AC electric field in the step (2) is 45-55 Hz; the energization voltage of the AC electric field is 2-8 V, and the energization time of the AC electric field is 2-5 hours.

The present invention also provides the yttria-stabilized zirconia powder prepared by the preparation method described in the above technical scheme, the yttria-stabilized zirconia powder has a core-shell structure, and the core-shell structure includes a zirconia core body and electrostatic Yttrium oxide shell layer for adsorption; the surface of the zirconia core body is negatively charged, and the yttrium oxide shell layer is composed of positively charged yttrium oxide particles on the surface;

The thickness of the yttrium oxide shell layer in the yttria-stabilized zirconia powder is 60-150 nm.

The present invention also provides a ceramic, which is obtained by pressing and sintering the yttria-stabilized zirconia powder described in the above technical solution as a raw material.

The invention provides a preparation method of yttrium oxide stabilized zirconia powder, comprising the following steps: dispersing yttrium oxide powder and cationic surfactant into deionized water to obtain yttrium oxide dispersion; and anionic surfactant dispersed in deionized water to obtain a zirconia dispersion; the particle size ratio of the yttrium oxide powder to the zirconia powder is 1:5 to 20; under the conditions of alternating electric field and stirring, the obtained The yttrium oxide dispersion is mixed with the zirconia dispersion and coated to obtain a slurry of yttrium oxide coated zirconia; the mass ratio of yttrium oxide to zirconia in the slurry is 1:4 to 20; for the obtained slurry The materials are dried and pulverized in sequence to obtain yttria-stabilized zirconia powder.

The present invention mixes the cationic surfactant with the yttrium oxide powder and the anionic surfactant with the zirconia powder, so that the surfaces of the yttrium oxide powder and the zirconia powder can be coated with the cationic surfactant and the anionic surfactant respectively. The positively charged yttrium oxide particles on the surface and the negatively charged zirconia particles on the surface are obtained; under the condition of alternating electric field and stirring, the positively charged yttrium oxide particles on the surface and the negatively charged zirconia particles on the surface are constantly moving, During the movement, the positive and negative charges act through Coulomb electrostatic attraction, causing the yttrium oxide particles and the zirconia particles to attract each other; and the particle size of the yttrium oxide particles is small, and the particle size of the zirconia particles is large. When the two particles are close to each other, the zirconia particles will The particles are inside, and the yttrium oxide particles are in the outer layer, forming a core-shell structure of yttrium oxide coated zirconia; in addition, because the surface of the yttrium oxide particles has a positive charge, the same charge repels each other, so that the yttrium oxide particles can be evenly arranged in the On the surface of the zirconia particles, a uniform yttrium oxide coating layer is formed. By using the yttria-stabilized zirconia powder prepared by the invention, ceramic products with uniform phase formation and good mechanical properties can be obtained.

The results of the examples show that the uniformity of the coating layer of the yttria-stabilized zirconia powder obtained in the present application is good, and the relative density of the obtained ceramics after sintering is 98.7-99.5%; the hardness reaches 1352-1432HV, and the fracture toughness reaches 4.47-4.82MPa · m ^1/2 .

Description of drawings

Fig. 1 is the effect comparison diagram of preparing yttria-stabilized zirconia powder by mechanical mixing method and the method of the present invention;

Fig. 2 is the schematic diagram of the mechanism of preparing yttrium oxide stabilized zirconia powder in the present invention;

Fig. 3 is the SEM picture of the obtained yttria-stabilized zirconia powder of embodiment 1;

Fig. 4 is the SEM picture of the obtained yttria-stabilized zirconia powder of comparative example 1;

5 is a TEM image of the yttria-stabilized zirconia powder obtained in Example 1.

Detailed ways

The invention provides a preparation method of yttria-stabilized zirconia powder, comprising the following steps:

(1) disperse the yttrium oxide powder and the cationic surfactant into deionized water to obtain the yttrium oxide dispersion;

Dispersing the zirconia powder and anionic surfactant into deionized water to obtain a zirconia dispersion;

The particle size ratio of the yttrium oxide powder to the zirconia powder is 1:5 to 20;

(2) Under alternating electric field and stirring conditions, the yttrium oxide dispersion liquid obtained in the step (1) is mixed with the zirconia dispersion liquid, and coated to obtain a slurry of yttria-coated zirconia; the slurry The mass ratio of yttrium oxide to zirconium oxide is 1:4～20;

(3) Drying and pulverizing the slurry obtained in the step (2) in sequence to obtain yttria-stabilized zirconia powder.

In the present invention, the raw materials and reagents used in the preparation method of the yttria-stabilized zirconia powder are commercially available products well known to those skilled in the art unless otherwise specified.

The invention disperses the yttrium oxide powder and the cationic surfactant into the deionized water to obtain the yttrium oxide dispersion liquid. In the present invention, the particle size of the yttrium oxide powder is preferably 40-60 nm, more preferably 45-55 nm. In the present invention, the cationic surfactant preferably includes cetylpyridinium chloride or cetyltrimethylammonium bromide (CTAB), more preferably cetyltrimethylammonium bromide.

In the present invention, the mass ratio of the yttrium oxide powder to the cationic surfactant is preferably 1:0.003-0.005, more preferably 1:0.004. In the present invention, the solid content is based on the mass percentage of the yttrium oxide powder in the total amount of the dispersion, and the solid content of the yttrium oxide dispersion is preferably 20-30%, more preferably 22-28%.

In the present invention, the preparation method of the yttrium oxide dispersion preferably includes:

dissolving the cationic surfactant in partially deionized water to obtain a deionized aqueous solution of the cationic surfactant;

After mixing the obtained cationic surfactant deionized water solution, yttrium oxide powder and the remaining deionized water, ball milling to obtain a yttrium oxide dispersion.

The present invention has no special requirements on the specific implementation of the dissolution, and those familiar to those skilled in the art can be used. In the present invention, when the cationic surfactant is CTAB, the dissolution temperature is preferably 40-60°C, more preferably 45-55°C, so as to accelerate the dissolution rate of CTAB.

The present invention has no special requirements on the concentration of the deionized aqueous solution of the cationic surfactant, as long as the cationic surfactant can be fully dissolved. In the present invention, the mass ratio of the cationic surfactant to the deionized water for dissolving is preferably 1:8-20, more preferably 1:10-15. In the present invention, the deionized water for dissolving the cationic surfactant is derived from the deionized water for the raw material of the yttrium oxide dispersion.

After obtaining the cationic surfactant deionized aqueous solution, the present invention mixes the cationic surfactant deionized aqueous solution, yttrium oxide powder and the remaining deionized water, and ball mills to obtain the yttrium oxide dispersion. In the present invention, there is no special requirement on the mixing method of the deionized aqueous solution of the surfactant, the yttrium oxide powder and the deionized water, and a mixing method well known to those skilled in the art can be used. After mixing, the present invention performs ball milling on the mixed material, so that the yttrium oxide powder and the cationic surfactant can be uniformly mixed, and then form positively charged yttrium oxide particles on the surface. In the present invention, the rotational speed of the ball mill is preferably 400-800 r/min, more preferably 450-700 r/min; the time of the ball mill is preferably 1-6 hours, more preferably 2-5 hours.

In the present invention, the zirconia powder and anionic surfactant are dispersed in deionized water to obtain a zirconia dispersion liquid. In the present invention, the particle size ratio of the yttrium oxide powder to the zirconia powder is preferably 1:5-20, more preferably 1:6-15. The present invention limits the particle size of the yttrium oxide powder and the zirconia powder to the above-mentioned range, so that the small particle size yttrium oxide can be used as a coating layer material to coat the surface of the large particle size zirconia. In the present invention, the anionic surfactant preferably includes sodium deoxycholate or polymethacrylic acid, more preferably sodium deoxycholate.

In the present invention, the mass ratio of the zirconia powder to the anionic surfactant is preferably 1:0.003-0.005, more preferably 1:0.004. In the present invention, the solid content is calculated by the mass percentage of the zirconia powder in the total amount of the zirconia dispersion, and the solid content of the zirconia dispersion is preferably 40-50%, more preferably 42-48%.

In the present invention, the preparation method of the zirconia dispersion preferably includes: mixing the zirconia powder, anionic surfactant and deionized water, and then ball milling to obtain the zirconia dispersion. In the present invention, there is no special requirement on the mixing method of the zirconia powder, anionic surfactant and deionized water, and a method well known to those skilled in the art can be used. After mixing, in the present invention, the mixed material is preferably ball-milled, so that the zirconia powder and the anionic surfactant can be uniformly mixed, and then zirconia particles with negatively charged surfaces can be obtained. In the present invention, the rotational speed of the ball mill is preferably 400-800 r/min, more preferably 450-750 r/min; the time of the ball mill is preferably 1-6 hours, more preferably 2-5 hours.

During ball milling, in terms of mass, the ball-to-material ratio of the ball mill is preferably 1-3:1, more preferably 2:1; the diameter of the balls for ball milling is preferably 4-9 mm, more preferably 5-8 mm; The material of the ball mill is preferably zirconia balls. The present invention has no special requirements on the specific implementation of the ball mill, and those familiar to those skilled in the art can be used.

In the present invention, the order of preparation of the yttrium oxide dispersion and the zirconia dispersion has no time sequence.

After obtaining the yttrium oxide dispersion and the zirconia dispersion, the present invention mixes the yttrium oxide dispersion and the zirconia dispersion under conditions of alternating electric field and stirring, and coats them to obtain a slurry of yttrium oxide-coated zirconia . In the present invention, the mass ratio of yttrium oxide in the yttrium oxide dispersion to zirconia in the zirconia dispersion is 1:3-20, more preferably 1:4-18, more preferably 1:5-15 . In the present invention, the mixing method is preferably dropwise addition, and the dropwise addition rate is preferably 0.8-2 mL/s, more preferably 1.0-1.8 mL/s, and more preferably 1.2-1.6 mL/s. In the present invention, the dropping may be adding the yttrium oxide dispersion liquid into the zirconia dispersion liquid dropwise, or adding the zirconia dispersion liquid into the yttrium oxide dispersion liquid dropwise. The present invention mixes the yttrium oxide dispersion liquid and the zirconium oxide dispersion liquid in a dropping manner, which can provide sufficient time for the coating of the yttrium oxide and the zirconium oxide, and avoid the influence of too much added amount on the uniformity of the coating layer.

In the present invention, the mixing and coating of the yttrium oxide dispersion liquid and the zirconium oxide dispersion liquid are carried out under the conditions of alternating electric field and stirring. In the present invention, the frequency of the AC electric field is preferably 45-55 Hz, more preferably 48-52 Hz; the energization voltage of the AC electric field is preferably 2-8 V, more preferably 3-7 V; the energization of the AC electric field The time is preferably 2 to 5 hours, more preferably 3 to 4 hours. In the present invention, the AC electric field of the coating condition is preferably set at the above-mentioned conditions to improve the coating effect and obtain yttria-stabilized zirconia powder with a uniform coating layer. The present invention has no special requirements on the specific manner of providing the AC electric field, and a method well known to those skilled in the art can be used.

In the present invention, the stirring speed is preferably 500-700 r/min, more preferably 550-650 r/min; the stirring time is preferably 2-5 hours, more preferably 2.5-4 hours.

The present invention mixes the yttrium oxide dispersion liquid and the zirconia dispersion liquid under the conditions of alternating electric field and stirring, so that the positively charged yttrium oxide particles on the surface and the negatively charged zirconia particles on the surface are continuously moved, and positively charged during the movement. , Negative charges attract each other through Coulomb electrostatic attraction to form yttria stabilized zirconia powder.

In order to clearly explain the coating effect of the present invention, the coating process of the present invention and the effect diagram of the obtained product are compared with the conventional mechanical mixing method. As shown in Figure 1, A represents the mechanical mixing method, and B represents the preparation method of the present invention, wherein Z represents zirconia, and Y represents yttrium oxide; as can be seen from Figure 1, under the conditions of using the same raw materials, the mechanical mixing method is used to prepare When yttrium oxide stabilizes zirconia powder, yttrium oxide and zirconia are mixed unevenly, and yttrium oxide does not form a uniform coating structure on the surface of zirconia; and using the preparation method of the present invention, yttrium oxide can be evenly coated on the surface of zirconia zirconium surface.

The mechanism of the present invention to realize uniform coating of zirconia powder by yttrium oxide is shown in Figure 2, in which Z represents zirconia, Y represents yttrium oxide, m represents anionic surfactants, n represents cationic surfactants, and I represents zirconia The process of coating anionic surfactant on the surface, II indicates the process of coating cationic surfactant on the surface of yttrium oxide, and III indicates the formation process of yttrium oxide stabilized zirconia powder.

As shown in Figure 2, after the anionic surfactant m is mixed with the zirconia powder Z in the present invention, the anionic surfactant m is coated on the surface of the zirconia powder Z to form negatively charged zirconia particles on the surface; After the surfactant n is mixed with the yttrium oxide powder Y, the cationic surfactant n coats the surface of the yttrium oxide powder Y to form yttrium oxide particles with negative charges on the surface; After the positively charged yttrium oxide particles are mixed, the positive and negative charges attract each other, and the particle size of the zirconia particles is larger, while the particle size of the yttrium oxide particles is smaller, so a core-shell structure of yttrium oxide-coated zirconia is formed; In addition, since the surface of yttrium oxide is positively charged, the same charge repels each other between yttrium oxide and yttrium oxide, so that positively charged yttrium oxide particles are evenly distributed on the surface of zirconia, avoiding accumulation, and then being coated Yttria-stabilized zirconia powder with a relatively uniform layer.

After the slurry is obtained, the present invention sequentially dries and pulverizes the slurry to obtain yttria-stabilized zirconia powder. In the present invention, the drying temperature is preferably 40-100°C, more preferably 45-90°C; the drying time is preferably 5-25h, more preferably 6-20h. The present invention has no special requirements on the specific implementation of the drying, and the methods well known to those skilled in the art can be used.

After the drying, the present invention pulverizes the dried material to obtain yttria-stabilized zirconia powder. In the present invention, the dried material is in the form of a block, which can be crushed to obtain yttria-stabilized zirconia powder. The present invention has no special requirements on the specific implementation of the pulverization, and the methods well known to those skilled in the art can be used.

After the pulverization, the present invention preferably sieves the pulverized material, and uses the undersize as yttria-stabilized zirconia powder. In the present invention, the sieve used for sieving is preferably 80-200 mesh, more preferably 100-150 mesh. The present invention has no special requirements on the specific implementation of the sieving, and the methods well known to those skilled in the art can be used.

The present invention provides the yttria-stabilized zirconia powder described in the above technical solution, the yttria-stabilized zirconia powder has a core-shell structure, and the core-shell structure includes a zirconia core body and an yttria shell adsorbed by electrostatic action layer; the surface of the zirconia core body is negatively charged, and the yttrium oxide shell layer is composed of yttrium oxide powder with a positive charge on the surface. In the present invention, the cationic surfactant coated with yttrium oxide and the anionic surfactant coated with zirconia surface are less, and the quality is negligible, and the mass ratio of the yttrium oxide shell layer to the zirconia core body is preferably It is consistent with the mass ratio of the yttrium oxide raw material to the zirconia raw material, and will not be repeated here. In the present invention, the thickness of the yttria shell layer in the yttria-stabilized zirconia powder is 60-150 nm, more preferably 80-120 nm.

In the present invention, the amount of anionic surfactant and cationic surfactant in the yttria-stabilized zirconia powder is small, and when used as a ceramic raw material, it can be removed by sintering in the process of preparing ceramics without affecting Sintering and mechanical properties of yttrium oxide stabilized zirconia peroxide powders.

The present invention also provides a ceramic, which is obtained by pressing and sintering the yttria-stabilized zirconia powder described in the above technical solution as a raw material.

In the present invention, the yttria-stabilized zirconia powder is first pressed to obtain a compact suitable for sintering. In the present invention, the pressing is preferably isostatic pressing, more preferably cold isostatic pressing. In the present invention, the pressure of the isostatic pressing is preferably 200-240MPa, more preferably 205-220MPa; the holding time of the isostatic pressing is preferably 8-12min, more preferably 9-10min; The isostatic pressing is preferably carried out at room temperature. The present invention has no special requirements on the specific implementation of the isostatic pressing, and those familiar to those skilled in the art can be used.

After pressing, the present invention sinters the compact obtained after pressing to obtain ceramics. In the present invention, the sintering temperature is preferably 1440-1480° C., more preferably 1445-1460° C.; the holding time is preferably 2.8-4 hours, more preferably 3-3.5 hours. After sintering, the present invention preferably cools the sintered compact obtained after sintering to obtain ceramics. The present invention has no special requirements on the cooling method, and those known to those skilled in the art can be used. In the embodiment of the present invention, the cooling is preferably natural cooling.

The ceramics in the invention have uniform phase structure and excellent mechanical properties. In the present invention, the hardness of the ceramic is preferably ≥1350HV, more preferably 1352-1432HV; the toughness of the ceramic is preferably ≥4.45MPa·m ^1/2 , more preferably 4.46-4.82MPa·m ^1/2 .

In order to further illustrate the present invention, the yttria-stabilized zirconia provided by the present invention and its preparation method and ceramics are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

Example 1

The particle size of zirconia powder is 300nm, and the particle size of yttrium oxide powder is 50nm; mix 800 parts of zirconia powder, 3.2 parts of sodium deoxycholate and 1000 parts of deionized water to obtain a zirconia dispersion; mix 200 parts of oxidized Yttrium powder, 0.8 part of cetyltrimethylammonium bromide and 300 parts of deionized water are mixed to obtain a yttrium oxide dispersion;

Put the zirconia dispersion into a glass container, and then apply an AC electric field with a voltage of 8V and a frequency of 50Hz. Under stirring, add the yttrium oxide dispersion dropwise at a rate of 1mL/s. After the addition is complete, continue stirring for 3h , to get the mixture;

The mixture was placed in a drying oven and dried at 40°C for 24 hours to obtain a dry block powder, which was ground and passed through an 80-mesh sieve, and the under-sieve was yttria-stabilized zirconia powder.

The obtained yttria-stabilized zirconia peroxide powder was sintered under the following conditions: keeping the pressure at 230 MPa for 9 minutes to obtain a molded body, then keeping the molded body at 1475°C for 4.5 hours, and cooling naturally to room temperature to obtain a ceramic.

Example 2

The particle size of zirconia powder is 500nm, and the particle size of yttrium oxide powder is 50nm; mix 850 parts of zirconia powder, 3.4 parts of polymethacrylic acid and 1200 parts of deionized water, and then ball mill for 3 hours under the condition of 480r/min , to obtain a zirconia dispersion;

Take 0.6 parts of cetyltrimethylammonium bromide and add it to 10mL of deionized deionized water, heat to 50°C and stir, stop stirring and heating after the solution is clear, and obtain cetyltrimethylammonium bromide deionized Aqueous solution; 150 parts of yttrium oxide powder was added to cetyltrimethylammonium bromide deionized aqueous solution, and ball milled for 3 hours under the condition of 480r/min to obtain a yttrium oxide dispersion;

Put the yttrium oxide dispersion into a glass container, and then apply an AC electric field with a voltage of 6V and a frequency of 48Hz. Under stirring conditions, add the zirconia dispersion dropwise at a rate of 1.2mL/s. After the dropwise addition, continue stirring 4h, obtain mixture;

The mixture was placed in a drying oven and dried at 60°C for 18 hours to obtain a dry block powder, which was ground and passed through a 150-mesh sieve, and the under-sieve was yttria-stabilized zirconia powder.

According to the method of Example 1, the yttria-stabilized zirconia powder obtained in this example was sintered to obtain ceramics, except that the pressure during compression molding was 208 MPa, the holding time was 8 minutes, the sintering temperature was 1500 ° C, and the holding time was 4 hours. .

Example 3

The particle size of zirconia powder is 300nm, and the particle size of yttrium oxide powder is 40nm; mix 900 parts of zirconia powder, 2.7 parts of sodium deoxycholate and 1200 parts of deionized water, and then ball mill for 4 hours under the condition of 400r/min , to obtain a zirconia dispersion;

Mix 100 parts of yttrium oxide powder, 0.3 parts of cetylpyridinium chloride and 200 parts of deionized water, and ball mill for 3 hours under the condition of 480 r/min to obtain a yttrium oxide dispersion;

Put the zirconia dispersion into a glass container, and then apply an AC electric field with a voltage of 4V and a frequency of 52Hz. Under stirring conditions, add the yttrium oxide dispersion dropwise at a rate of 1.2mL/s. After the dropwise addition, continue stirring 3h, obtain mixture;

The mixture was placed in a drying oven and dried at 80°C for 12 hours to obtain a dry block powder, which was ground and passed through a 120-mesh sieve, and the under-sieve was yttria-stabilized zirconia powder.

According to the method of Example 1, the yttria-stabilized zirconia powder obtained in this example was sintered to obtain ceramic products. The difference is that the pressure during compression molding is 225 MPa, the holding time is 11 minutes, the sintering temperature is 1450 ° C, and the holding time is 3h.

Example 4

The particle size of zirconia powder is 500nm, and the particle size of yttrium oxide powder is 60nm; 950 parts of zirconia powder, 4.75 parts of polysodium methacrylate and 1500 parts of deionized water are mixed, and then ball milled under the condition of 480r/min 3h, obtain zirconia dispersion liquid;

Take 0.15 parts of cetyltrimethylammonium bromide with a mass ratio of 1:1 and add it to 8mL deionized deionized water, heat to 50°C and stir, stop stirring and heating after the solution is clarified to obtain cetyltrimethylammonium bromide Ammonium bromide deionized aqueous solution; 50 parts of yttrium oxide powder was added to hexadecyltrimethylammonium bromide deionized aqueous solution, and ball milled for 3 hours under the condition of 480r/min to obtain a yttrium oxide dispersion;

Put the yttrium oxide dispersion into a glass container, and then apply an AC electric field with a voltage of 2V and a frequency of 50Hz. Under stirring conditions, add the zirconia dispersion dropwise at a rate of 1.5mL/s. After the dropwise addition, continue stirring 3h, obtain mixture;

The mixed material was placed in a drying oven, and dried at 100°C for 6 hours to obtain a dry block powder, which was ground and passed through a 100-mesh sieve, and the under-sieve was yttria-stabilized zirconia powder.

According to the method of Example 1, the yttria-stabilized zirconia powder obtained in this example was sintered to obtain ceramic products. The difference is that the pressure during compression molding is 200 MPa, the holding time is 10 minutes, the sintering temperature is 1485 ° C, and the holding time is 3.5h.

Comparative example 1

According to the scheme of Example 1, the raw materials were taken, and the yttria-stabilized zirconia powder was prepared by the solid phase mechanical mixing method. The rotational speed of the ball mill was 480r/min, the ball milling time was 12h, and the ball-to-material ratio was 1.5:1. The performance parameters of the yttria-stabilized zirconia powder were tested according to the method of Example 1, and the results are listed in Table 1. Ceramics were prepared according to the conditions of Example 4, and the properties of the obtained ceramics are listed in Table 1.

The morphology of the yttria-stabilized zirconia powder obtained in Example 1 and Comparative Example 1 was characterized by a scanning electron microscope, as shown in FIGS. 3 and 4 . As can be seen from Figure 3, the obtained yttria-stabilized zirconia powder prepared by the present invention has a uniform particle size, while the yttria-stabilized zirconia powder prepared in Comparative Example 1 (Figure 4) has serious agglomeration, uneven particle size, and no formation A uniform coating layer affects the sintering performance of the powder, which in turn affects the phase structure and mechanical properties of the ceramic material.

The coating layer of the yttria-stabilized zirconia powder obtained in the embodiment was characterized by a transmission electron microscope, as shown in FIG. 5 . It can be seen from the figure that the powder prepared by the present invention is yttria-coated zirconia composite powder, and the thickness of the yttrium oxide coating layer (the light-colored part in the figure) is uniform.

The particle size of the yttria-stabilized zirconia powder in Examples 1-4 and Comparative Example 1 was tested by a laser particle size analyzer, and the test results are shown in Table 1. The particle size range in Table 1 represents the minimum particle size and maximum particle size of the obtained yttria-stabilized zirconia powder. It can be seen from the data that the particle size distribution range of the yttria-stabilized zirconia powder prepared by the present invention is narrow, indicating that the powder better uniformity. The particle size distribution range of the sample obtained in Comparative Example 1 is relatively wide, and the uniformity is relatively poor.

The hardness and toughness of the ceramic samples of Examples 1-4 and Comparative Example 1 were tested by the indentation method under a force of 20 kg and held for 15 s. The test results are shown in Table 1.

Table 1 Examples 1-4 and Comparative Example 1 Yttria-stabilized zirconia powder and ceramic properties

It can be seen from Table 1 that the hardness and toughness of the ceramic samples prepared by using the yttria-stabilized zirconia powder obtained in the present invention have been significantly improved compared with Comparative Example 1, indicating that the yttria-stabilized zirconia powder provided by the present invention The problem of poor particle size uniformity of the powder is overcome, and the sintering performance of the powder is improved.

In summary, the preparation method provided by the present invention can obtain a uniform coating layer of the yttria-stabilized zirconia powder, and the particle size of the powder reaches the nanometer level, which is beneficial to improving the sintering performance of the powder. Using the yttria-stabilized zirconia powder obtained in the present invention as a raw material, the ceramics obtained after sintering have good hardness, fracture toughness and relative density, indicating that when the yttria-stabilized zirconia provided by the present invention is used as a ceramic raw material, it can obtain Ceramic products with good mechanical properties.

In addition, the method provided by the invention is simple and easy to control, has low preparation cost, and is suitable for large-scale popularization and use.

Although the above-mentioned embodiment has described the present invention in detail, it is only a part of the embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments according to the present embodiment without inventive step. These embodiments All belong to the protection scope of the present invention.

Claims (10)

1. A preparation method for yttrium oxide stabilized zirconia powder, comprising the steps of: (1) disperse the yttrium oxide powder and the cationic surfactant into deionized water to obtain the yttrium oxide dispersion; Dispersing the zirconia powder and anionic surfactant into deionized water to obtain a zirconia dispersion; The particle size ratio of the yttrium oxide powder to the zirconia powder is 1:5 to 20; (2) Under alternating electric field and stirring conditions, the yttrium oxide dispersion liquid obtained in the step (1) is mixed with the zirconia dispersion liquid, and coated to obtain a slurry of yttria-coated zirconia; the slurry The mass ratio of yttrium oxide to zirconium oxide is 1:4～20; (3) Drying and pulverizing the slurry obtained in the step (2) in sequence to obtain yttria-stabilized zirconia powder. 2. the preparation method as claimed in claim 1, is characterized in that, in described step (1), the mass ratio of yttrium oxide powder and cationic surfactant is 1:0.003～0.005, and the mass ratio of described yttrium oxide dispersion liquid The solid content is 20-30%, and the solid content is calculated by the mass percentage of yttrium oxide in the total amount of the yttrium oxide dispersion; The mass ratio of zirconia powder to anionic surfactant is 1:0.003-0.005, the solid content of the zirconia dispersion is 20-30%, and the solid content is the mass of zirconia in the total amount of zirconia dispersion percentage meter. 3. The preparation method according to claim 1 or 2, characterized in that the particle size of the yttrium oxide powder in the step (1) is 40-60 nm. 4. the preparation method as claimed in claim 1 or 2 is characterized in that, in described step (1), cationic surfactant comprises cetylpyridinium chloride or cetyltrimethylammonium bromide; The anionic surfactants include sodium deoxycholate or polymethacrylic acid. 5. the preparation method as claimed in claim 1 or 2, is characterized in that, the preparation method of yttrium oxide dispersion liquid comprises in the described step (1): dissolving the cationic surfactant in partially deionized water to obtain a deionized aqueous solution of the cationic surfactant; After mixing the deionized aqueous solution of the cationic surfactant, the yttrium oxide powder and the remaining deionized water, ball milling to obtain the yttrium oxide dispersion. 6. the preparation method as claimed in claim 1 or 2, is characterized in that, the preparation method of zirconia dispersion liquid in described step (1) comprises: with described zirconia powder, anionic surfactant and deionized water Ball milling after mixing to obtain a zirconia dispersion. 7. The preparation method according to claim 1, characterized in that, the mixing mode of the yttrium oxide dispersion and the zirconia dispersion in the step (2) is dropwise addition, and the speed of the dropwise addition is 0.8～2mL/ s. 8. The preparation method according to claim 1 or 7, wherein the frequency of the AC electric field in the step (2) is 45 to 55 Hz; the energization voltage of the AC electric field is 2 to 8V, and the AC electric field The power-on time is 2 to 5 hours. 9. The yttria-stabilized zirconia powder prepared by the preparation method according to any one of claims 1 to 8, the yttria-stabilized zirconia powder has a core-shell structure, and the core-shell structure comprises a zirconia core body and An yttrium oxide shell layer adsorbed by electrostatic interaction; the surface of the zirconia core body is negatively charged, and the yttrium oxide shell layer is composed of positively charged yttrium oxide particles on the surface; The thickness of the yttrium oxide shell layer in the yttria-stabilized zirconia powder is 60-150 nm. 10. A ceramic, which is obtained by pressing and sintering the yttria-stabilized zirconia powder according to claim 9 as a raw material.