Alumina ceramics, their preparation methods and applications

Abstract

This invention provides an alumina ceramic, its preparation method, and its applications. The alumina ceramic, by mass parts, comprises: an alumina self-stabilizing system and a zirconium oxide self-stabilizing system; the alumina self-stabilizing system comprises 70-90 parts alumina and 1-2 parts stearic acid, and the zirconium oxide self-stabilizing system comprises 10-30 parts yttrium-stabilized nano-zirconia, 1-2 parts stearic acid, and 1-2 parts polyvinyl alcohol; wherein the median particle size of the alumina is 0.1 μm-0.25 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm-50 nm. Through rational formulation of the components, selecting alumina and yttrium-stabilized nano-zirconia of specific particle sizes, and combining them with other raw materials, the resulting alumina ceramic exhibits high density, hardness, and fracture toughness, making it particularly suitable for preparing medical devices, bioceramics, or semiconductor device packaging components.

Description

Technical Field

[0001] This invention relates to the field of ceramic preparation technology, specifically to an alumina ceramic, its preparation method, and its application. Background Technology

[0002] Alumina ceramics possess excellent wear resistance, chemical corrosion resistance, high thermal conductivity, high insulation, high temperature resistance, high hardness, and good biocompatibility, and are widely used in semiconductor equipment components, electronic components, medical devices, aerospace and other fields.

[0003] Because the structure of pure alumina is bonded by ionic bonds, it is difficult for it to slip under external force. It has the characteristics of low diffusion coefficient and difficulty in sintering. After high-temperature sintering, the grains generally grow to 2-10 μm, and the internal pores are difficult to completely eliminate. Therefore, its density is low, its mechanical properties are poor, and its fracture toughness is low. This disadvantage greatly limits its use. Summary of the Invention

[0004] Therefore, it is necessary to provide an alumina ceramic with high density, hardness, flexural strength and fracture toughness.

[0005] In one aspect, the present invention provides an alumina ceramic, the raw materials of which, by mass parts, include: an alumina self-stabilizing system and a zirconia self-stabilizing system; the alumina self-stabilizing system includes 70 to 90 parts of alumina and 1 to 2 parts of stearic acid, and the zirconia self-stabilizing system includes 10 to 30 parts of yttrium-stabilized nano-zirconia, 1 to 2 parts of stearic acid and 1 to 2 parts of polyvinyl alcohol;

[0006] The median particle size of the alumina is 0.1 μm to 0.25 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm to 50 nm.

[0007] In one embodiment, the alumina is 75 to 85 parts by mass;

[0008] And / or, the mass fraction of the yttrium-stabilized nano-zirconia is 15 to 25 parts.

[0009] In one embodiment, the flexural strength of the alumina ceramic is 400 MPa to 1100 MPa;

[0010] And / or, the alumina ceramic has a density of 97% to 99.9%;

[0011] And / or, the hardness of the alumina ceramic is 1700Hv to 1900Hv;

[0012] And / or, the Weibull modulus of the alumina ceramic is 5 to 8.

[0013] In another aspect, the present invention provides a method for preparing alumina ceramics, characterized by comprising the following steps:

[0014] Mix 70 to 90 parts of alumina and 1 to 2 parts of stearic acid, and mill them to prepare a self-stabilizing alumina system.

[0015] A self-stabilizing zirconia system was prepared by mixing 10 to 30 parts of yttrium-stabilized nano-zirconia, 1 to 2 parts of stearic acid, and 1 to 2 parts of polyvinyl alcohol and then milling the mixture.

[0016] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled to prepare a mixture.

[0017] The mixture is granulated, shaped, and sintered to prepare a pre-fired body;

[0018] The pre-fired body is subjected to hot isostatic pressing to prepare the alumina ceramic.

[0019] The median particle size of alumina in the alumina self-stabilizing system is 0.1 μm to 0.25 μm, and the median particle size of yttrium-stabilized nano-zirconia in the zirconia self-stabilizing system is 10 nm to 50 nm.

[0020] In one embodiment, the sand milling is a conventional sand milling or an ultrasonic-assisted high-energy sand milling; the sand milling time is 1 hour to 4 hours.

[0021] In one embodiment, the sintering temperature is 1350°C to 1450°C.

[0022] In one embodiment, the pressure of the hot isostatic pressing is 150 MPa to 200 MPa.

[0023] In one embodiment, the sintering time is 2h to 4h; and / or the hot isostatic pressing temperature is 1300℃ to 1400℃ and the time is 1h to 3h.

[0024] In one embodiment, the molding method is isostatic pressing, injection molding, or dry pressing.

[0025] In another aspect, the present invention provides the application of the above-described alumina ceramic or the alumina ceramic prepared according to the above-described alumina ceramic preparation method in the preparation of medical devices, bioceramics or semiconductor device packaging elements.

[0026] The alumina ceramics described above, through the rational combination of components, by selecting alumina and yttrium-stabilized nano-zirconia with specific particle sizes and combining them with other raw materials, have high density, hardness and fracture toughness.

[0027] In addition, the aforementioned alumina ceramics also have a high Weibull modulus. Detailed Implementation

[0028] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0030] One embodiment of the present invention provides an alumina ceramic, the raw materials of which, by mass parts, include: an alumina self-stabilizing system and a zirconium oxide self-stabilizing system; the alumina self-stabilizing system includes 70 to 90 parts of alumina and 1 to 2 parts of stearic acid, and the zirconium oxide self-stabilizing system includes 10 to 30 parts of yttrium-stabilized nano-zirconia, 1 to 2 parts of stearic acid and 1 to 2 parts of polyvinyl alcohol;

[0031] In the above-mentioned self-stabilized alumina system, the median particle size (D50) of alumina is 0.1 μm to 0.25 μm.

[0032] In the above-mentioned self-stabilized zirconium oxide system, the median particle size of yttrium-stabilized nano-zirconia is 10 nm to 50 nm.

[0033] In alumina ceramics, the ratio of the alumina self-stabilizing system to the zirconium oxide self-stabilizing system is 1:1.

[0034] In alumina ceramics, the mass fraction of alumina is 70 to 90 parts, specifically 72, 75, 78, 80, 85, 88, or 90 parts.

[0035] In one example, the alumina is in the range of 75 to 85 parts by mass.

[0036] In alumina ceramics, the mass fraction of yttrium-stabilized nano-zirconia is 10 to 30 parts, specifically 10, 15, 18, 20, 23, 25, or 30 parts.

[0037] In one example, the mass fraction of yttrium-stabilized nano-zirconia is 15 to 25 parts.

[0038] In one example, the flexural strength of the alumina ceramic is 400 MPa to 1100 MPa.

[0039] In one example, the density of the alumina ceramic was 97%–99.9%.

[0040] In one example, the hardness of the alumina ceramic is 1700 Hv to 1900 Hv.

[0041] In one example, the Weibull modulus of the alumina ceramic is 5 to 8.

[0042] Another embodiment of the present invention provides a method for preparing alumina ceramics, comprising the following steps S100 to S500.

[0043] Step S100: Mix 70 to 90 parts of alumina and 1 to 2 parts of stearic acid, and mill them to prepare a self-stabilized alumina system.

[0044] Optionally, in the alumina ceramic, the mass fraction of alumina is 72 parts, 75 parts, 78 parts, 80 parts, 85 parts, 88 parts, or 90 parts.

[0045] In one example, the mass fraction of alumina is 75 to 85 parts;

[0046] In one example, the sanding is either ordinary sanding or ultrasonic-assisted sanding; the sanding time is 1 hour to 4 hours.

[0047] In one example, the conventional sand milling is performed using a nano-sand mill.

[0048] In one example, the sand milling is ultrasonic-assisted sand milling; the sand milling time is 2h to 4h.

[0049] In one example, the median particle size of alumina in the alumina self-stabilized system is 0.1 μm to 0.25 μm.

[0050] Step S200: Mix 10 to 30 parts of yttrium-stabilized nano-zirconia, 1 to 2 parts of stearic acid and 1 to 2 parts of polyvinyl alcohol, and mill to prepare a zirconia self-stabilized system.

[0051] Optionally, the mass fraction of yttrium-stabilized nano-zirconia in the alumina ceramic is 10 to 30 parts, specifically, the mass fraction of yttrium-stabilized nano-zirconia is 10, 15, 18, 20, 23, 25, or 30 parts.

[0052] In one example, the mass fraction of yttrium-stabilized nano-zirconia is 15 to 25 parts.

[0053] In one example, the sand milling is a conventional sand milling or an ultrasonic-assisted sand milling; the sand milling time is 1 hour to 4 hours.

[0054] In one example, the sand milling is ultrasonic-assisted sand milling; the sand milling time is 1 hour to 3 hours.

[0055] In one example, the median particle size of yttrium-stabilized nano-zirconia in the zirconia self-stabilized system is 10 nm to 50 nm.

[0056] Step S300: Mix the alumina self-stabilizing system and the zirconium oxide self-stabilizing system, and mill them to prepare a mixture.

[0057] In one example, the sand milling is a conventional sand milling or an ultrasonic-assisted sand milling; the sand milling time is 1 hour to 4 hours.

[0058] In one example, the sand milling is a regular sand milling process; the sand milling time is 1 hour to 3 hours.

[0059] Step S400: The mixture is granulated, shaped and sintered to prepare a pre-fired body.

[0060] In one example, the molding method is isostatic pressing, injection molding, or dry pressing.

[0061] In one example, the sintering temperature is 1350°C to 1450°C.

[0062] Specifically, the sintering temperature is 1350℃, 1380℃, 1400℃, 1430℃ or 1450℃.

[0063] In one example, the sintering time is 2h to 4h.

[0064] Step S500: The pre-fired body is subjected to hot isostatic pressing to prepare the alumina ceramic.

[0065] In one example, the pressure of the hot isostatic pressing is 150 MPa to 200 MPa.

[0066] Specifically, the pressure of the hot isostatic pressing is 150MPa, 160MPa, 170MPa, 180MPa, 190MPa or 200MPa.

[0067] In one example, the hot isostatic pressing temperature is 1300℃~1400℃ and the time is 1h~3h.

[0068] This invention refines alumina ceramic powder and introduces yttrium-stabilized nano-zirconia dispersed in the grain boundaries of alumina to achieve grain boundary strengthening and inhibit rapid grain boundary movement, thereby controlling grain growth. This enables low-temperature sintering to obtain alumina structures with fine grain size and high density, improving the mechanical properties of composite alumina ceramics and further enhancing their fracture toughness.

[0069] Another embodiment of the present invention provides the application of the above-described alumina ceramic or the alumina ceramic prepared according to the above-described alumina ceramic preparation method in the preparation of medical devices, bioceramics or semiconductor device packaging elements.

[0070] The alumina ceramics described above, through the rational combination of components, by selecting alumina and yttrium-stabilized nano-zirconia with specific particle sizes and combining them with other raw materials, have high density, hardness and fracture toughness.

[0071] In addition, the aforementioned alumina ceramics also have a high Weibull modulus.

[0072] The following are specific examples.

[0073] Example 1:

[0074] The alumina ceramic of this embodiment, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.3 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1.0 part stearic acid, and 1.7 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm.

[0075] The preparation steps of alumina ceramics are as follows:

[0076] 70 parts of alumina and 1.3 parts of stearic acid were mixed and ultrasonically assisted high-energy milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0077] 30 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.7 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 10 nm.

[0078] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0079] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0080] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1400℃ for 2 hours to obtain a pre-sintered body.

[0081] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0082] Example 2:

[0083] The alumina ceramic of this embodiment, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 80 parts alumina and 1.35 parts stearic acid, and the zirconia self-stabilizing system comprises 20 parts yttrium-stabilized nano-zirconia, 1.0 part stearic acid, and 1.74 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 30 nm.

[0084] The preparation steps of alumina ceramics are as follows:

[0085] 80 parts of alumina and 1.35 parts of stearic acid were mixed and ultrasonically assisted high-energy sand milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0086] 20 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.74 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 30 nm.

[0087] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0088] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0089] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1400℃ for 4 hours to obtain a pre-sintered body.

[0090] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0091] Example 3:

[0092] The alumina ceramic of this embodiment, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 90 parts alumina and 1.38 parts stearic acid, and the zirconia self-stabilizing system comprises 10 parts yttrium-stabilized nano-zirconia, 1.02 parts stearic acid, and 1.82 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 50 nm.

[0093] The preparation steps of alumina ceramics are as follows:

[0094] 90 parts of alumina and 1.38 parts of stearic acid were mixed and ultrasonically assisted high-energy sand milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0095] 10 parts of yttrium-stabilized nano-zirconia, 1.02 parts of stearic acid and 1.82 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 50 nm.

[0096] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0097] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0098] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1450℃ for 2 hours to obtain a pre-sintered body.

[0099] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1400℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0100] Comparative Example 1:

[0101] The alumina ceramic of this comparative example, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.3 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1.0 part stearic acid, and 1.7 parts polyvinyl alcohol. The median particle size of the alumina is 1 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm.

[0102] The preparation steps of alumina ceramics are as follows:

[0103] 70 parts of alumina and 1.3 parts of stearic acid were mixed, ultrasonically assisted high-energy sand milling was performed for 2 hours, and the mixture was repeated 3 times. The mixture was then sieved through a 1000-mesh sieve to obtain an alumina self-stabilized system with a median particle size (D50) of 1 μm.

[0104] 30 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.7 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 10 nm.

[0105] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0106] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0107] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1400℃ for 2 hours to obtain a pre-sintered body.

[0108] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0109] Comparative Example 2:

[0110] The alumina ceramic of this comparative example, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.35 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1.0 part stearic acid, and 1.74 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 200 nm.

[0111] The preparation steps of alumina ceramics are as follows:

[0112] 70 parts of alumina and 1.35 parts of stearic acid were mixed and ultrasonically assisted high-energy sand milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0113] 30 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.74 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 200 nm.

[0114] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0115] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0116] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1400℃ for 2 hours to obtain a pre-sintered body.

[0117] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0118] Comparative Example 3:

[0119] The alumina ceramic of this comparative example, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.05 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1 part stearic acid, and 1.1 parts polyvinyl alcohol. The median particle size of the alumina is 1 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 200 nm.

[0120] The preparation steps of alumina ceramics are as follows:

[0121] 70 parts of alumina and 1.05 parts of stearic acid were mixed, ultrasonically assisted high-energy sand milling was performed for 2 hours, and the mixture was repeated 3 times. The mixture was then sieved through a 1000-mesh sieve to obtain an alumina self-stabilized system with a median particle size (D50) of 1 μm.

[0122] 30 parts of yttrium-stabilized nano-zirconia, 1 part of stearic acid and 1.1 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 200 nm.

[0123] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0124] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0125] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1400℃ for 2 hours to obtain a pre-sintered body.

[0126] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0127] Comparative Example 4:

[0128] The alumina ceramic of this comparative example, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.3 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1 part stearic acid, and 1.7 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm.

[0129] The preparation steps of alumina ceramics are as follows:

[0130] 70 parts of alumina and 1.3 parts of stearic acid were mixed and ultrasonically assisted high-energy milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0131] 30 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.7 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 10 nm.

[0132] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0133] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0134] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1300℃ for 2 hours to obtain a pre-sintered body.

[0135] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0136] Comparative Example 5:

[0137] The alumina ceramic of this comparative example, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.3 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1.0 part stearic acid, and 1.7 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm.

[0138] The preparation steps of alumina ceramics are as follows:

[0139] 70 parts of alumina and 1.3 parts of stearic acid were mixed and ultrasonically assisted high-energy milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0140] 30 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.7 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 10 nm.

[0141] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0142] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0143] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1500℃ for 2 hours to obtain a pre-sintered body.

[0144] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 150MPa for 2 hours to obtain alumina ceramic.

[0145] Comparative Example 6:

[0146] The alumina ceramic of this comparative example, by mass parts, consists of: an alumina self-stabilizing system and a zirconia self-stabilizing system, with a part ratio of 1:1. The alumina self-stabilizing system comprises 70 parts alumina and 1.3 parts stearic acid, and the zirconia self-stabilizing system comprises 30 parts yttrium-stabilized nano-zirconia, 1.0 part stearic acid, and 1.7 parts polyvinyl alcohol. The median particle size of the alumina is 0.2 μm, and the median particle size of the yttrium-stabilized nano-zirconia is 10 nm.

[0147] The preparation steps of alumina ceramics are as follows:

[0148] 70 parts of alumina and 1.3 parts of stearic acid were mixed and ultrasonically assisted high-energy milling was carried out for 2 hours. This process was repeated 3 times. The mixture was then sieved through 1000 mesh, 3000 mesh and 5000 mesh screens in three stages to obtain an alumina self-stabilized system with a median particle size (D50) of 0.2 μm.

[0149] 30 parts of yttrium-stabilized nano-zirconia, 1.0 part of stearic acid and 1.7 parts of polyvinyl alcohol were mixed and ultrasonically assisted high-energy sand milling was performed for 1 hour to obtain a zirconia self-stabilized system with a median particle size of 10 nm.

[0150] The alumina self-stabilizing system and the zirconium oxide self-stabilizing system are mixed and milled in ordinary sand for 1-3 hours to obtain a mixture.

[0151] The mixture is spray-granulated to obtain uniform alumina composite powder;

[0152] The alumina composite powder was isostatically pressed, the binder was removed, and it was sintered at 1300℃ for 2 hours to obtain a pre-sintered body.

[0153] The pre-fired body was subjected to hot isostatic pressing at a temperature of 1350℃ and a pressure of 100MPa for 2 hours to obtain alumina ceramic.

[0154] The raw material ratios for the alumina ceramics in Examples 1-3 and Comparative Examples 1-6 can be found in Table 1.

[0155] Table 1 shows the raw material composition of the alumina ceramics in Examples 1-3 and 1-6.

[0156]

[0157]

[0158] The preparation process parameters of the alumina ceramics in Examples 1-3 and Comparative Examples 1-6 can be found in Table 2.

[0159] Table 2 shows the preparation process parameters of alumina ceramics in Examples 1-3 and 1-6.

[0160] Sintering temperature Sintering time Hot isostatic pressing temperature Hot isostatic pressure Hot isostatic pressing time Example 1 1400℃ 2h 1350℃ 150MPa 2h Example 2 1400℃ 2h 1350℃ 150MPa 2h Example 3 1450℃ 2h 1400℃ 150MPa 2h Comparative Example 1 1400℃ 2h 1350℃ 150MPa 2h Comparative Example 2 1400℃ 2h 1350℃ 150MPa 2h Comparative Example 3 1400℃ 2h 1350℃ 150MPa 2h Comparative Example 4 1300℃ 2h 1350℃ 150MPa 2h Comparative Example 5 1500℃ 2h 1350℃ 150MPa 2h Comparative Example 6 1300℃ 2h 1350℃ 100MPa 2h

[0161] The alumina ceramics of Examples 1-3 and Comparative Examples 1-6 were subjected to tests for density, hardness, flexural strength, Weibull modulus, and fracture toughness. Specifically, density was tested according to ISO 18754, hardness according to ISO 14705, flexural strength according to ISO 14704, Weibull modulus according to ISO 20501, and fracture toughness according to ISO 23146. The test results are recorded in Table 3.

[0162] Table 3 shows the density, hardness, flexural strength, Weibull modulus, and fracture toughness of the alumina ceramics in Examples 1-3 and Comparative Examples 1-6.

[0163]

[0164]

[0165] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0166] The above-described embodiments are merely illustrative of several implementation methods of the present invention, facilitating a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. An aluminum oxide ceramic, characterized by, The preparation method comprises the following steps: an alumina self-stabilizing system is prepared by mixing 70-90 parts of alumina and 1-2 parts of stearic acid, and sand milling; a zirconia self-stabilizing system is prepared by mixing 10-30 parts of yttrium-stabilized nano-zirconia, 1-2 parts of stearic acid and 1-2 parts of polyvinyl alcohol, and sand milling; the alumina self-stabilizing system and the zirconia self-stabilizing system are mixed at a mass ratio of 1:1, and sand milling is performed to prepare a mixture; the mixture is granulated, molded and sintered to prepare a pre-sintered body; the pre-sintered body is subjected to hot isostatic pressing at a pressure of 150-200 MPa and a temperature of 1300-1400℃ to prepare the alumina ceramic; in the alumina self-stabilizing system, the median particle size of the alumina is 0.1-0.25 μm, and in the zirconia self-stabilizing system, the median particle size of the yttrium-stabilized nano-zirconia is 10-50 nm; the sintering temperature is 1350-1450℃; the bending strength of the alumina ceramic is 1020-1100 MPa, and the hardness of the alumina ceramic is 1700-1900 Hv.

2. The aluminum oxide ceramic according to claim 1, characterized in that the mass fraction of the alumina is 75-85 parts.

3. The aluminum oxide ceramic according to claim 1, characterized by the mass fraction of the yttrium-stabilized nano-zirconia is 15-25 parts.

4. The aluminum oxide ceramic according to claim 1, characterized by the density of the alumina ceramic is 97-99.9%.

5. The aluminum oxide ceramic of claim 1, wherein, the Weibull modulus of the alumina ceramic is 5-8.

6. The aluminum oxide ceramic of claim 1, wherein, the sand milling is ordinary sand milling or ultrasonic-assisted sand milling; and the sand milling time is 1-4 h.

7. The aluminum oxide ceramic according to any one of claims 1 and 6, characterized by the sintering time is 2-4 h.

8. The aluminum oxide ceramic according to any one of claims 1 and 6, characterized by the hot isostatic pressing time is 1-3 h.

9. The aluminum oxide ceramic according to any one of claims 1 and 6, characterized by the molding method is isostatic pressing molding, injection molding or dry pressing molding.

10. Use of the alumina ceramic according to any one of claims 1-9 in the preparation of a medical device, a bioceramic or a semiconductor device packaging element.

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