Preparation method and application of zirconia ceramic

Abstract

The invention belongs to the technical field of zirconia ceramic preparation, and particularly relates to a preparation method and application of zirconia ceramic. The preparation method of the zirconia ceramic comprises the following steps: carrying out hydrothermal reaction on zirconium oxychloride, cobalt chloride, hydroxyapatite and sodium carboxymethyl cellulose to obtain a zirconia precursor; mixing the zirconium oxide precursor with diatomite, polyvinyl alcohol and absolute ethyl alcohol, and performing ball milling and calcination to obtain modified zirconium oxide powder; finally, adding the modified zirconium oxide powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin, polyamide, polyphenylene sulfide and polybutylene terephthalate into a stirring mixer, uniformly mixing to form slurry, performing injection molding to obtain a green body, and performing degreasing and sintering treatment to obtain the zirconium oxide ceramic. The tolerance of the sintered zirconia ceramic is about + / -0.5 [mu] m, the processing application of precise ceramic structural parts can be realized, and the method has a wide market application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of zirconia ceramic preparation, and specifically relates to a preparation method and application of zirconia ceramics. Background Art

[0002] High-purity zirconia powder has a white appearance and extremely stable chemical properties, showing good insolubility in acid, alkali, and salt solutions. At the same time, this material has low thermal conductivity and excellent thermal stability. From the crystal structure perspective, zirconia exists in three low-pressure phases: monoclinic phase (M, space group P21 / C), tetragonal phase (T), and cubic phase (C). At low temperatures, the monoclinic phase is the thermodynamically stable state; when the temperature rises to about 1400 K, a first-order displacement-type martensitic transformation occurs and it transforms into the tetragonal phase; further heating to about 2600 K, the tetragonal phase will transform into the cubic fluorite structure. Zirconia exhibits excellent mechanical properties, high temperature resistance, and high strength, and performs outstandingly in the field of structural ceramics. It can be used to manufacture sound-absorbing and sound-insulating components, filter media, valve components, etc., and occupies an important position in the fields of thermal barrier coatings, high-temperature composite materials, piezoelectric ceramics, and optical fiber ferrules.

[0003] An optical fiber ferrule is a cylinder used for precise alignment in an optical fiber connector plug, with a micropore in the center for fixing the optical fiber. Its main material is nano-zirconia, which has the characteristics of good thermal stability, high hardness, wear resistance, and high processing accuracy. However, there are still the following problems when producing structural parts with zirconia ceramics: (1) Zirconia ceramics are prone to deformation; (2) The tolerance after sintering of zirconia ceramics is large, and currently it can only reach ±3 μm, which is difficult to meet the accuracy requirements for precision parts. Therefore, there is an urgent need to develop a zirconia ceramic with high strength and a smaller tolerance after sintering. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of zirconia ceramics and the application of the zirconia ceramics obtained by the method in the field of optical fiber ferrules.

[0005] The implementation process of the present invention is as follows: A preparation method of zirconia ceramics includes the following steps: (1) Dissolve zirconium oxychloride and cobalt chloride in water, then add hydroxyapatite and sodium carboxymethylcellulose, and after ultrasonic treatment, obtain a uniformly dispersed suspension; (2) Transfer the suspension obtained in step (1) to a reaction kettle for hydrothermal reaction. After the reaction is completed, centrifuge, wash, and dry to obtain a zirconia precursor; (3) Add the zirconia precursor, diatomite, polyvinyl alcohol, and absolute ethanol to a ball mill tank for ball milling. After the ball milling is completed, dry the powder and place it in a tubular furnace for calcination to obtain a modified zirconia powder; (4) Add the modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin wax, polyamide, polyphenylene sulfide, and polybutylene terephthalate into a stirring mixer and mix them evenly to form a slurry. (5) According to the shape of the required ceramic structural part, inject the slurry to form a green body of the ceramic structural part. (6) After degreasing and sintering the green body of the ceramic structural part, obtain zirconia ceramics.

[0006] Further, in step (1), the molar ratio of zirconium oxychloride, cobalt chloride, hydroxyapatite, and sodium carboxymethylcellulose is 40:(1 - 1.2):(0.9 - 1):0.5; the molar volume ratio of the zirconium oxychloride to water is 40 mmol:(100 - 120) mL.

[0007] Further, in step (2), the temperature of the hydrothermal reaction is 180 - 190 °C, and the reaction time is 7 - 8 hours.

[0008] Further, in step (3), the weight ratio of the zirconia precursor, diatomite, polyvinyl alcohol, and absolute ethanol is 5:(0.3 - 0.5):(0.4 - 0.5):2; the rotation speed of the ball milling is 500 - 600 r / min; the ball milling time is 10 - 12 hours; the calcination temperature is 950 - 1000 °C, and the calcination time is 2 - 2.5 hours.

[0009] Further, in step (4), the weight ratio of the modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin wax, polyamide, polyphenylene sulfide, and polybutylene terephthalate is 100:(3 - 5):(7 - 13):(15 - 25):(40 - 65):(5 - 8):(10 - 12):(4 - 7).

[0010] Further, in step (5), the temperature of the injection molding is 160 - 170 °C, the molding pressure is 1 - 1.2 MPa, and the molding time is 30 - 35 s.

[0011] Further, in step (6), the degreasing process is to place the green body of the ceramic structural part in a degreasing furnace and keep it at 450 - 500 °C for 3 - 4 hours to obtain a degreased blank of the ceramic structural part.

[0012] Further, in step (6), the sintering process is to place the degreased blank of the ceramic structural part in a sintering furnace and keep it at 1500 - 1550 °C for 3 - 4 hours.

[0013] The zirconia ceramics prepared by the above method.

[0014] The application of the above zirconia ceramics in the field of optical fiber ferrules.

[0015] Positive effects of the present invention: (1) During the preparation process of the modified zirconia powder, cobalt chloride, hydroxyapatite, diatomite and polyvinyl alcohol are added to increase the strength of the zirconia powder. In addition, through calcination, the lattice defects of the modified zirconia powder are repaired, and under the action of high temperature, the specific surface area decreases, the porosity decreases, and the density increases.

[0016] (2) The modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin, polyamide, polyphenylene sulfide and polybutylene terephthalate are mixed and then injection molded. Due to the addition of thermoplastic phenolic resin, polypropylene, polyethylene, paraffin, polyamide, polyphenylene sulfide and polybutylene terephthalate, the tolerance of the zirconia ceramic made from the modified zirconia powder is about ±0.5 μm after debinding and sintering, which can realize the processing and application of precision ceramic structural parts and has broad market application prospects. Description of the drawings

[0017] Figure 1 It is the process flow chart of the preparation of the zirconia ceramic described in the present invention. Specific embodiments

[0018] The present invention will be further described below in conjunction with embodiments. [[ID=!17]]

[0019] First, the present invention provides a method for preparing a zirconia ceramic, which includes the following steps: (1) Dissolve 40 mmol of zirconium oxychloride and (1 - 1.2) mmol of cobalt chloride in (100 - 120) mL of water, then add (0.9 - 1) mmol of hydroxyapatite and 0.5 mmol of sodium carboxymethylcellulose, and after ultrasonic treatment, obtain a uniformly dispersed suspension; (2) Transfer the suspension obtained in step (1) to a reaction kettle, carry out hydrothermal reaction at 180 - 190 °C for 7 - 8 hours, and after the reaction is completed, obtain a zirconia precursor through centrifugation, washing and drying; (3) Add the zirconia precursor, diatomite, polyvinyl alcohol and absolute ethanol to a ball mill tank, carry out ball milling at a speed of 500 - 600 r / min for 10 - 12 hours, and after the ball milling is completed, dry the powder and place it in a tubular furnace for calcination at 950 - 1000 °C for 2 - 2.5 hours to obtain a modified zirconia powder; the weight ratio of the zirconia precursor, diatomite, polyvinyl alcohol and absolute ethanol is 5:(0.3 - 0.5):(0.4 - 0.5):2; (4) Add the modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin wax, polyamide, polyphenylene sulfide, and polybutylene terephthalate into a stirring mixer and mix them evenly to form a slurry; the weight ratio of the modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin wax, polyamide, polyphenylene sulfide, and polybutylene terephthalate is 100: (3~5): (7~13): (15~25): (40~65): (5~8): (10~12): (4~7); (5) According to the shape of the required ceramic structural part, inject the slurry to form a green body of the ceramic structural part; the injection molding temperature is 160~170°C, the molding pressure is 1~1.2 MPa, and the molding time is 30~35 s; (6) After degreasing and sintering the green body of the ceramic structural part, zirconia ceramics are obtained. The degreasing process is to place the green body of the ceramic structural part in a degreasing furnace and keep it at 450~500°C for 3~4 hours to obtain a degreased blank of the ceramic structural part; the sintering process is to place the degreased blank of the ceramic structural part in a sintering furnace and keep it at 1500~1550°C for 3~4 hours.

[0020] In the second aspect, the present invention provides the zirconia ceramics prepared by the above method.

[0021] In the third aspect, the present invention provides the application of the above zirconia ceramics in the field of optical fiber ferrules.

[0022] Example 1 The preparation method of the zirconia ceramics in this example includes the following steps: (1) Dissolve 40 mmol of zirconium oxychloride and 1.1 mmol of cobalt chloride in 110 mL of water, then add 0.95 mmol of hydroxyapatite and 0.5 mmol of sodium carboxymethyl cellulose, and after ultrasonic treatment, a uniformly dispersed suspension is obtained; (2) Transfer the suspension obtained in step (1) to a reaction kettle, carry out a hydrothermal reaction at 185°C for 7.5 hours, and after the reaction is completed, centrifuge, wash, and dry to obtain a zirconia precursor; (3) Add 5 parts by weight of the zirconia precursor, 0.4 parts by weight of diatomaceous earth, 0.45 parts by weight of polyvinyl alcohol, and 2 parts by weight of absolute ethanol into a ball mill tank, carry out ball milling at a speed of 550 r / min for 11 hours, and after the ball milling is completed, dry the powder and place it in a tubular furnace for calcination at 980°C for 2 hours to obtain a modified zirconia powder; (4) Add 100 parts by weight of modified zirconia powder, 4 parts by weight of thermoplastic phenolic resin, 10 parts by weight of polypropylene, 20 parts by weight of polyethylene, 50 parts by weight of paraffin wax, 7 parts by weight of polyamide, 11 parts by weight of polyphenylene sulfide, and 6 parts by weight of polybutylene terephthalate into a stirring mixer and mix evenly to form a slurry; (5) According to the shape of the required ceramic structural part, inject the slurry to form a green body of the ceramic structural part; the temperature of the injection molding is 165 °C, the molding pressure is 1.1 MPa, and the molding time is 33 s; (6) After degreasing and sintering the green body of the ceramic structural part, zirconia ceramics are obtained. The degreasing process is to place the green body of the ceramic structural part in a degreasing furnace and keep it at 480 °C for 3.5 hours to obtain a degreased blank of the ceramic structural part; the sintering process is to place the degreased blank of the ceramic structural part in a sintering furnace and keep it at 1520 °C for 3.5 hours.

[0023] Example 2 The preparation method of the zirconia ceramics described in this example includes the following steps: (1) Dissolve 40 mmol of zirconium oxychloride and 1 mmol of cobalt chloride in 100 mL of water, then add 1 mmol of hydroxyapatite and 0.5 mmol of sodium carboxymethyl cellulose, and after ultrasonic treatment, a uniformly dispersed suspension is obtained; (2) Transfer the suspension obtained in step (1) to a reaction kettle, carry out hydrothermal reaction at 180 °C for 8 hours, and after centrifugation, washing, and drying after the reaction, a zirconia precursor is obtained; (3) Add 5 parts by weight of the zirconia precursor, 0.5 parts by weight of diatomite, 0.4 parts by weight of polyvinyl alcohol, and 2 parts by weight of absolute ethanol into a ball milling tank, carry out ball milling at a rotation speed of 600 r / min for 10 hours, and after drying after ball milling, place the powder in a tubular furnace and calcine it at 1000 °C for 2 hours to obtain modified zirconia powder; (4) Add 100 parts by weight of modified zirconia powder, 3 parts by weight of thermoplastic phenolic resin, 13 parts by weight of polypropylene, 15 parts by weight of polyethylene, 40 parts by weight of paraffin wax, 8 parts by weight of polyamide, 12 parts by weight of polyphenylene sulfide, and 7 parts by weight of polybutylene terephthalate into a stirring mixer and mix evenly to form a slurry; (5) According to the shape of the required ceramic structural part, inject the slurry to form a green body of the ceramic structural part; the temperature of the injection molding is 160 °C, the molding pressure is 1.2 MPa, and the molding time is 35 s; (6) After degreasing and sintering the green body of the ceramic structural part, zirconia ceramics are obtained. The degreasing process is to place the green body of the ceramic structural part in a degreasing furnace and keep it at 500 °C for 3 hours to obtain the degreased blank of the ceramic structural part; the sintering process is to place the degreased blank of the ceramic structural part in a sintering furnace and keep it at 1500 °C for 4 hours.

[0024] Example 3 The preparation method of the zirconia ceramics described in this example includes the following steps: (1) Dissolve 40 mmol of zirconium oxychloride and 1.2 mmol of cobalt chloride in 120 mL of water, then add 0.9 mmol of hydroxyapatite and 0.5 mmol of sodium carboxymethylcellulose, and after ultrasonic treatment, a uniformly dispersed suspension is obtained; (2) Transfer the suspension obtained in step (1) to a reaction kettle, carry out hydrothermal reaction at 190 °C for 7 hours, and after centrifugation, washing and drying after the reaction, a zirconia precursor is obtained; (3) Add 5 parts by weight of zirconia precursor, 0.3 parts by weight of diatomite, 0.5 parts by weight of polyvinyl alcohol and 2 parts by weight of absolute ethanol to a ball milling tank, carry out ball milling at a speed of 500 r / min for 12 hours, and after drying after ball milling, place the powder in a tube furnace and calcine at 950 °C for 2.5 hours to obtain modified zirconia powder; (4) Add 100 parts by weight of modified zirconia powder, 5 parts by weight of thermoplastic phenolic resin, 7 parts by weight of polypropylene, 25 parts by weight of polyethylene, 65 parts by weight of paraffin, 5 parts by weight of polyamide, 10 parts by weight of polyphenylene sulfide and 4 parts by weight of polybutylene terephthalate into a stirring mixer and mix evenly to form a slurry; (5) According to the shape of the required ceramic structural part, inject the slurry to form a green body of the ceramic structural part; the temperature of the injection molding is 170 °C, the molding pressure is 1 MPa, and the molding time is 30 s; (6) After degreasing and sintering the green body of the ceramic structural part, zirconia ceramics are obtained. The degreasing process is to place the green body of the ceramic structural part in a degreasing furnace and keep it at 450 °C for 4 hours to obtain the degreased blank of the ceramic structural part; the sintering process is to place the degreased blank of the ceramic structural part in a sintering furnace and keep it at 1550 °C for 3 hours.

[0025] Example 4 The preparation method of the zirconia fiber ceramic ferrule described in this example includes the following steps: (1) Dissolve 40 mmol of zirconium oxychloride and 1 mmol of cobalt chloride in 110 mL of water, then add 1) mmol of hydroxyapatite and 0.5 mmol of sodium carboxymethylcellulose, and after ultrasonic treatment, a uniformly dispersed suspension is obtained; (2) Transfer the suspension obtained in step (1) to a reaction kettle, carry out hydrothermal reaction at 190 °C for 8 hours. After the reaction ends, centrifuge, wash, and dry to obtain a zirconia precursor; (3) Add 5 parts by weight of zirconia precursor, 0.4 parts by weight of diatomite, 0.5 parts by weight of polyvinyl alcohol, and 2 parts by weight of absolute ethanol to a ball milling tank, carry out ball milling at a rotation speed of 600 r / min for 12 hours. After the ball milling ends, dry and place the powder in a tube furnace for calcination at 1000 °C for 2.5 hours to obtain modified zirconia powder; (4) Add 100 parts by weight of modified zirconia powder, 5 parts by weight of thermoplastic phenolic resin, 10 parts by weight of polypropylene, 16 parts by weight of polyethylene, 65 parts by weight of paraffin wax, 8 parts by weight of polyamide, 10 parts by weight of polyphenylene sulfide, and 6 parts by weight of polybutylene terephthalate into a stirring mixer for uniform mixing to form a slurry; (5) According to the shape of the required optical fiber ceramic ferrule, inject the slurry to form a green body of the optical fiber ceramic ferrule; the injection molding temperature is 165 °C, the molding pressure is 1.2 MPa, and the molding time is 35 s; (6) After degreasing and sintering the green body of the optical fiber ceramic ferrule, obtain a zirconia optical fiber ceramic ferrule. The degreasing process is to place the green body of the optical fiber ceramic ferrule in a degreasing furnace and keep it at 500 °C for 4 hours to obtain a degreased blank of the optical fiber ceramic ferrule; the sintering process is to place the degreased blank of the optical fiber ceramic ferrule in a sintering furnace and keep it at 1500 °C for 4 hours.

[0026] Comparative Example 1 It is the same as the method and parameters of Example 1, the difference is that: cobalt chloride is not added in step (1).

[0027] Comparative Example 2 It is the same as the method and parameters of Example 1, the difference is that: hydroxyapatite is not added in step (1).

[0028] Comparative Example 3 It is the same as the method and parameters of Example 1, the difference is that: diatomite is not added in step (3).

[0029] Comparative Example 4 It is the same as the method and parameters of Example 1, the difference is that: polyvinyl alcohol is not added in step (3).

[0030] Comparative Example 5 It is the same as the method and parameters of Example 1, the difference is that: thermoplastic phenolic resin, polypropylene, polyethylene, paraffin wax, polyamide, polyphenylene sulfide, and polybutylene terephthalate are not added in step (4).

[0031] The density, hardness, and inner diameter tolerance of the zirconia ceramic green bodies prepared in Examples 1-4 and Comparative Examples 1-5 were tested.

[0032] Table 1 Data table of density, hardness, and inner diameter tolerance of zirconia ceramics

[0033] As can be seen from Table 1, the preparation methods of Examples 1-4 obtained zirconia ceramics with high density, high hardness, and stable dimensions after sintering. However, after changing the raw material formula in Comparative Examples 1-5, the density and hardness of the prepared zirconia ceramics decreased significantly. Moreover, in Comparative Example 5, after changing the additives, the inner diameter tolerance increased significantly, and the dimensions of the zirconia ceramics were unstable after sintering, affecting the precision of the ceramic structural parts.

[0034] Those skilled in the art will readily conceive of other embodiments of the present application after considering the specification and the content disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include the common general knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and the embodiments are only regarded as exemplary, and the present application is not limited to the precise structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. A method for preparing zirconia ceramics, characterized in that, It includes the following steps: (1) Dissolve zirconium oxychloride and cobalt chloride in water, then add hydroxyapatite and sodium carboxymethylcellulose. After ultrasonic treatment, a uniformly dispersed suspension is obtained; (2) Transfer the suspension obtained in step (1) to a reaction kettle for hydrothermal reaction. After the reaction is completed, it is centrifuged, washed, and dried to obtain a zirconia precursor; (3) Add the zirconia precursor, diatomite, polyvinyl alcohol, and absolute ethanol to a ball mill tank for ball milling. After the ball milling is completed, the powder is dried and then placed in a tube furnace for calcination to obtain a modified zirconia powder; (4) Add the modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin, polyamide, polyphenylene sulfide, and polybutylene terephthalate to a stirring mixer for uniform mixing to form a slurry; (5) According to the shape of the required ceramic structural part, inject the slurry to form a green body of the ceramic structural part; (6) After degreasing and sintering the green body of the ceramic structural part, zirconia ceramics are obtained.

2. The preparation method of the zirconia ceramic according to claim 1, characterized in that: In step (1), the molar ratio of zirconium oxychloride, cobalt chloride, hydroxyapatite, and sodium carboxymethylcellulose is 40:(1 - 1.2):(0.9 - 1):0.5; the molar volume ratio of zirconium oxychloride to water is 40 mmol:(100 - 120) mL.

3. The preparation method of the zirconia ceramic according to claim 1, characterized in that: In step (2), the temperature of the hydrothermal reaction is 180 - 190 °C, and the reaction time is 7 - 8 hours.

4. The preparation method of the zirconia ceramic according to claim 1, characterized in that: In step (3), the weight ratio of the zirconia precursor, diatomite, polyvinyl alcohol, and absolute ethanol is 5:(0.3 - 0.5):(0.4 - 0.5):2; the rotation speed of the ball milling is 500 - 600 r / min; the ball milling time is 10 - 12 hours; the calcination temperature is 950 - 1000 °C, and the calcination time is 2 - 2.5 hours.

5. The preparation method of the zirconia ceramic according to claim 1, wherein: In step (4), the weight ratio of the modified zirconia powder, thermoplastic phenolic resin, polypropylene, polyethylene, paraffin, polyamide, polyphenylene sulfide, and polybutylene terephthalate is 100:(3 - 5):(7 - 13):(15 - 25):(40 - 65):(5 - 8):(10 - 12):(4 - 7).

6. The preparation method of the zirconia ceramic according to claim 1, wherein: In step (5), the temperature of the injection molding is 160 - 170 °C, the molding pressure is 1 - 1.2 MPa, and the molding time is 30 - 35 s.

7. The preparation method of the zirconia ceramic according to claim 1, wherein: In step (6), the degreasing process is to place the green body of the ceramic structural part in a degreasing furnace and keep it at 450 - 500 °C for 3 - 4 hours to obtain a degreased blank of the ceramic structural part.

8. The preparation method of the zirconia ceramic according to claim 1, wherein: In step (6), the sintering process is to place the degreased blank of the ceramic structural part in a sintering furnace and keep it at 1500 - 1550 °C for 3 - 4 hours.

9. Zirconia ceramics prepared by the method described in claim 1.

10. Application of the zirconia ceramics described in claim 9 in the field of optical fiber ferrules.

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