Modified ZTA composite ceramic spray granulation powder as well as preparation method and application thereof

Abstract

The invention discloses modified ZTA composite ceramic spray granulation powder as well as a preparation method and application thereof, and preparation raw materials comprise multi-scale aluminum oxide which comprises at least two kinds of nanometer aluminum oxide with different particle sizes; nano ZrO2 is modified; the nano composite powder is prepared from nano Cr2O3 and nano MnO; a binder; and a dispersant. The fine, medium and coarse nano aluminum oxide particles are sequentially mixed after the nano ZrO2 is modified, so that the agglomeration of the nano particles is effectively avoided, and the porosity optimization is realized; nano Cr2O3 and nano MnO are introduced, Al < 3 + > in Al2O3 crystal lattices is partially replaced by Cr < 3 + > ions, lattice distortion is caused, dislocation motion is hindered, the hardness and strength of the material are improved, the Cr < 3 + > ions are dissolved into the Al2O3 crystal lattices, a stable Cr2O3-Al2O3 solid solution can be generated at high temperature, the grain boundary binding energy is improved, the abnormal growth of Al2O3 crystal grains is inhibited, and the purposes of strong grain boundary and high compactness are synchronously achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of ceramic materials, and particularly relates to a modified ZTA composite ceramic spray granulation powder, a preparation method and an application thereof. Background Art

[0002] Zirconia-toughened alumina (ZTA) ceramics are widely used in cutting tools, bioceramics, and other fields because they combine the high hardness of alumina with the toughening properties of zirconia. In traditional ZTA preparation, alumina is typically prepared using a single particle size, resulting in low particle packing density and the formation of pores after sintering. While zirconia improves toughness, it is prone to agglomeration, affecting dispersion uniformity. Furthermore, due to its different particle size from alumina, achieving multi-scale particle synergistic strengthening has become a major technical challenge in the industry. Summary of the Invention

[0003] In order to solve the problems in the prior art, the purpose of the present invention is to provide a modified ZTA composite ceramic spray granulation powder and a preparation method and application thereof.

[0004] In order to achieve the above-mentioned purpose and the above-mentioned technical effect, the technical solution adopted by the present invention is:

[0005] A modified ZTA composite ceramic spray granulation powder, the raw materials for its preparation include:

[0006] Multi-scale alumina, including nano-alumina with at least two different particle sizes;

[0007] Modified nano ZrO2;

[0008] Nanocomposite powder, including nano-Cr2O3 and nano-MnO;

[0009] Adhesive;

[0010] Dispersant.

[0011] Furthermore, the mass ratio of the multi-scale alumina, modified nano ZrO2, nano composite powder, binder and dispersant is (64.5-88.49): (10-25): (0.5-5): (1-5): (0.01-0.5).

[0012] Furthermore, the multi-scale alumina is formed by compounding three nano-alumina with different particle sizes.

[0013] Furthermore, the multi-scale alumina is compounded by mixing nano alumina coarse particles with a particle size of 3-5 μm, nano alumina medium particles with a particle size of 1-2 μm, and nano alumina fine particles with a particle size of 0.3-0.8 μm in a mass ratio of (4-6): (2-4): (1-3).

[0014] Furthermore, the modified nano ZrO2 is ZrO2 surface-modified by a silane coupling agent, and has a particle size of 5-50 nm.

[0015] Furthermore, the mass ratio of the nano-Cr2O3 to the nano-MnO is (1.5-5): (1-2).

[0016] The present invention also discloses a method for preparing a modified ZTA composite ceramic spray granulation powder, comprising the following steps:

[0017] 1) Preparation of modified nano ZrO2;

[0018] 2) The modified nano-ZrO2 and nano-alumina fine particles with a particle size of 0.3-0.8 μm are subjected to nano-scale coating and compounding by high-speed ball milling at a speed of 300-600 rpm and a mixing time of 2-4 hours to form a ZrO2@Al2O3 composite powder;

[0019] 3) ball-milling the ZrO2@Al2O3 composite powder obtained in step 2) with medium-sized nano-alumina particles with a particle size of 1-2 μm, then adding coarse nano-alumina particles with a particle size of 3-5 μm and continuing to ball-mill and mix evenly, and then adding the nano-composite powder and continuing to ball-mill and mix evenly to obtain a composite powder;

[0020] 4) The composite powder obtained in step 3) is mixed uniformly with deionized water and a dispersant by ball milling, and then a binder is added and mixed uniformly by ball milling at a pH of 9-10;

[0021] 5) Spray granulation: Control the inlet air temperature at 180-220°C, the outlet temperature at 90-100°C, and the atomization pressure at 0.3-0.6 MPa to obtain the desired modified ZTA composite ceramic spray granulation powder.

[0022] Furthermore, in step 1), the preparation step of the modified nano ZrO2 includes:

[0023] Dissolve the silane coupling agent in anhydrous ethanol, add nano zirconium oxide, disperse by ultrasonic for 30-60 minutes, dry and activate at 70-90℃ to obtain the desired modified nano ZrO2.

[0024] Furthermore, in step 4), after adding the nanocomposite powder, the reactor is first operated at a speed of 150-250 rpm for 0.5-1 h, and then operated at a speed of 380-450 rpm for 2-3 h.

[0025] The invention also discloses an application of modified ZTA composite ceramic spray granulation powder in preparing the modified ZTA composite ceramic.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) The present invention uses three different particle sizes of nano-alumina: coarse (3-5μm), medium (1-2μm), and fine (0.3-0.8μm) mixed in a specific ratio, which is conducive to forming a densely packed structure and reducing sintering shrinkage; modified nano-ZrO2 is first mixed with fine (0.3-0.8μm) nano-alumina, and then mixed with medium (1-2μm) nano-alumina and coarse (3-5μm) nano-alumina in sequence, effectively avoiding nanoparticle agglomeration, which is conducive to improving particle uniformity and achieving optimal porosity;

[0028] 2) Nano ZrO2 modified and mixed with nano alumina can avoid the agglomeration of nano particles;

[0029] 3) The present invention introduces nano-Cr2O3 and nano-MnO, through Cr 3+ Ions partially replace Al in the Al2O3 lattice 3+ , causing lattice distortion, hindering dislocation movement, and helping to improve the hardness and strength of the material. 3+ Ions dissolve into the Al2O3 lattice and form a stable Cr2O3-Al2O3 solid solution at high temperature, which improves the grain boundary binding energy, inhibits the abnormal growth of Al2O3 grains, and hinders grain boundary migration. Nano-Cr2O3 and nano-MnO can form a Mn-Al-O low-temperature eutectic phase to fill the gaps between particles and improve density. By strengthening the grain boundaries with Cr2O3 and filling the gaps between particles with MnO, the goals of strong grain boundaries and high density can be achieved simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is an electron microscope image of Example 1 of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0032] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0033] In one aspect, the present invention discloses a modified ZTA composite ceramic spray granulation powder, the preparation raw materials of which include: multi-scale alumina, including at least two nano-alumina with different particle sizes;

[0034] Modified nano ZrO2;

[0035] Nanocomposite powder, including nano-Cr2O3 and nano-MnO;

[0036] Adhesive;

[0037] dispersants;

[0038] Among them, the mass ratio of multi-scale alumina, modified nano ZrO2, nano composite powder, binder and dispersant is (64.5-88.49): (10-25): (0.5-5): (1-5): (0.01-0.5).

[0039] In some embodiments, the multi-scale alumina is formed by compounding three nano-alumina particles of different particle sizes. In some more specific embodiments, the multi-scale alumina is formed by compounding coarse nano-alumina particles with a particle size of 3-5 μm, medium nano-alumina particles with a particle size of 1-2 μm, and fine nano-alumina particles with a particle size of 0.3-0.8 μm in a mass ratio of (4-6): (2-4): (1-3).

[0040] In some embodiments, the modified nano ZrO2 is ZrO2 surface-modified by a silane coupling agent, and has a particle size of 5-50 nm.

[0041] In some embodiments, the mass ratio of nano-Cr2O3 to nano-MnO is (1.5-5): (1-2). In some more specific embodiments, the nano-composite powder is prepared by the following steps:

[0042] Ammonia water is added dropwise to the Cr(NO3)3 solution, the temperature is controlled at 5°C in an ice bath, and the reaction is stopped when the pH is 7.5-8 to generate a Cr(OH)3 sol to avoid the generation of by-products. The solution is then spray-freeze-dried to obtain nano-Cr(OH)3 powder, which is then thermally decomposed in an argon atmosphere at 300-500°C to obtain nano-Cr2O3 (α-Cr2O3) with no agglomeration and a particle size of 30-100nm. The problem of uneven dispersion of nano-Cr2O3 can be solved by introducing nano-Cr(OH)3 powder. Based on conventional modification technology, stearic acid (soluble in ethanol) is used to modify the nano-Cr2O3 and graft carboxyl functional groups. Oleylamine (soluble in toluene) is used to modify the nano-MnO with a particle size of 200-400nm and graft amino functional groups. After modification, the solution is mixed at 60-100°C to obtain the desired nano-composite powder.

[0043] The effects of introducing nano-Cr2O3 and nano-MnO in the present invention are:

[0044] Cr 3+ Ions partially replace Al in the Al2O3 lattice 3+ , causing lattice distortion, hindering dislocation movement, and increasing hardness and strength, Cr 3+The ions dissolve into the Al2O3 lattice to form a stable Cr2O3-Al2O3 solid solution at high temperature, which improves the grain boundary binding energy, inhibits the abnormal growth of Al2O3 grains, hinders grain boundary migration, and can also form a Mn-Al-O low-temperature eutectic phase to fill the gaps between particles and improve density. By strengthening the grain boundaries with Cr2O3 and filling the gaps between particles with MnO, the goals of strong grain boundaries and high density are achieved simultaneously.

[0045] On the other hand, the present invention also discloses a method for preparing a modified ZTA composite ceramic spray granulation powder, comprising the following steps:

[0046] 1) Preparation of modified nano ZrO2:

[0047] Dissolve the silane coupling agent in anhydrous ethanol, add nano zirconium oxide, ultrasonically disperse for 30-60 minutes, dry and activate at 70-90℃ to obtain the desired modified nano ZrO2;

[0048] 2) The modified nano-ZrO2 is combined with nano-alumina particles with a particle size of 0.3-0.8 μm by high-speed ball milling for nano-scale coating and compounding at a speed of 300-600 rpm and a mixing time of 2-4 hours to form a ZrO2@Al2O3 composite powder, which can solve the problem of nano-ZrO2 dispersion;

[0049] 3) The ZrO2@Al2O3 composite powder obtained in step 2) is first ball-milled with medium nano-alumina particles having a particle size of 1-2 μm, and then coarse nano-alumina particles having a particle size of 3-5 μm are added and the mixture is further ball-milled and mixed, and then the nano-composite powder is added and the mixture is further ball-milled to obtain a composite powder; by mixing the fine, medium, and coarse nano-alumina particles in this order, nano-particle agglomeration is effectively avoided, thereby improving particle uniformity and optimizing porosity;

[0050] 4) The composite powder obtained in step 3) is mixed uniformly with deionized water and a dispersant (ammonium polyacrylate) by ball milling, and then a binder (PVA) is added and the mixture is mixed uniformly by ball milling at a pH of 9-10;

[0051] 5) Spray granulation: The desired modified ZTA composite ceramic spray granulation powder can be obtained by using a spray drying method, controlling the inlet air temperature at 180-220°C, the outlet temperature at 90-100°C, and the atomization pressure at 0.3-0.6 MPa.

[0052] In step 4), after adding the nanocomposite powder, the reactor is first operated at a speed of 150-250 rpm for 0.5-1 h to break up soft agglomerates, and then operated at a speed of 380-450 rpm for 2-3 h to achieve nano-scale dispersion.

[0053] The invention also discloses an application of modified ZTA composite ceramic spray granulation powder in preparing the modified ZTA composite ceramic.

[0054] Example 1

[0055] A modified ZTA composite ceramic spray granulation powder, the raw materials for its preparation include:

[0056] Multi-scale alumina is made by compounding 3μm nano-alumina coarse particles, 1μm nano-alumina medium particles, and 0.3μm nano-alumina fine particles in a mass ratio of 5:3:2.

[0057] The modified nano ZrO2 after surface modification by silane coupling agent KH-560 has a particle size of 40 nm;

[0058] Nano-composite powder, including nano-Cr2O3 and nano-MnO, wherein the mass ratio of nano-Cr2O3 to nano-MnO is 3:1;

[0059] Adhesive PVA;

[0060] Dispersant ammonium polyacrylate;

[0061] Among them, the mass ratio of multi-scale alumina, modified nano-ZrO2, nano-composite powder, binder and dispersant is 72.5:20:5:2:0.5.

[0062] In this embodiment, the nanocomposite powder is prepared by the following steps:

[0063] Ammonia water is added dropwise to the Cr(NO3)3 solution, the temperature is controlled at 5°C in an ice bath, and the reaction is stopped when the pH is 8 to generate a Cr(OH)3 sol to avoid the formation of by-products. The solution is then spray-freeze-dried to obtain nano-Cr(OH)3 powder, which is then thermally decomposed in an argon atmosphere at 400°C to obtain nano-Cr2O3 (α-Cr2O3) with no agglomeration and a particle size of 50nm. The problem of uneven dispersion of nano-Cr2O3 can be solved by introducing nano-Cr(OH)3 powder. Based on conventional modification technology, stearic acid (soluble in ethanol) is used to modify nano-Cr2O3 and graft carboxyl functional groups. Oleylamine (soluble in toluene) is used to modify nano-MnO with a particle size of 300nm and graft amino functional groups that can react with carboxyl functional groups. After modification, the solutions are mixed at 80°C to obtain the desired nano-composite powder.

[0064] The effects of introducing nano-Cr2O3 and nano-MnO in the present invention are:

[0065] Cr 3+ Ions partially replace Al in the Al2O3 lattice 3+ , causing lattice distortion, hindering dislocation movement, and increasing hardness and strength, Cr 3+The ions dissolve into the Al2O3 lattice to form a stable Cr2O3-Al2O3 solid solution at high temperature, which improves the grain boundary binding energy, inhibits the abnormal growth of Al2O3 grains, hinders grain boundary migration, and can also form a Mn-Al-O low-temperature eutectic phase to fill the gaps between particles and improve density. By strengthening the grain boundaries with Cr2O3 and filling the gaps between particles with MnO, the goals of strong grain boundaries and high density are achieved simultaneously.

[0066] A method for preparing a modified ZTA composite ceramic spray granulation powder comprises the following steps:

[0067] 1) Preparation of modified nano ZrO2:

[0068] Dissolve the silane coupling agent in anhydrous ethanol, add nano zirconium oxide, ultrasonically disperse for 50 minutes, dry and activate at 80℃ to obtain the desired modified nano ZrO2.

[0069] 2) The modified nano-ZrO2 and nano-alumina fine particles with a particle size of 0.3 μm were coated and compounded at the nanoscale by high-speed ball milling at a speed of 500 rpm and a mixing time of 3 hours to form ZrO2@Al2O3 composite powder, which can solve the problem of nano-ZrO2 dispersion;

[0070] 3) The ZrO2@Al2O3 composite powder obtained in step 2) was first ball-milled with medium nano-alumina particles with a particle size of 1 μm at a speed of 300 rpm for 2 hours to uniformly mix, and then coarse nano-alumina particles with a particle size of 3 μm were added and continued to be ball-milled and mixed uniformly at a speed of 300 rpm for 2 hours. Then, the nano-composite powder was added and continued to be ball-milled and mixed uniformly at a speed of 300 rpm for 2 hours to obtain a composite powder. By mixing the fine, medium, and coarse nano-alumina particles in this order, nano-particle agglomeration is effectively avoided, which is beneficial to improving particle uniformity and achieving optimal porosity.

[0071] 4) The composite powder obtained in step 3) is mixed uniformly with deionized water and dispersant ammonium polyacrylate by ball milling, and then a binder PVA is added and mixed uniformly by ball milling at pH = 9;

[0072] 5) Spray granulation: The desired modified ZTA composite ceramic spray granulation powder can be obtained by using a spray drying method with the air inlet temperature controlled at 200°C, the outlet temperature at 90°C, and the atomization pressure at 0.3 MPa.

[0073] In step 4), after adding the nanocomposite powder, the mixture was first run at 150 rpm for 1 h to break up the soft agglomerates, and then run at 450 rpm for 2 h to achieve nano-scale dispersion.

[0074] Application of a modified ZTA composite ceramic spray granulation powder in preparing a modified ZTA composite ceramic comprises the following steps:

[0075] Dry pressing and gradient sintering of modified ZTA composite ceramic spray granulation powder:

[0076] Stage I: heating to 600-700℃ at 3-5℃ / min, keeping at this temperature for 1-2h to remove the binder;

[0077] Stage II: heating to 1450-1600℃ at 5-8℃ / min;

[0078] Stage III: Keep the temperature at 1550-1580℃ for 2-4h, during which a mixture of hydrogen and nitrogen is introduced to inhibit the reduction of Cr2O3;

[0079] Stage IV: Cool to 900-1000°C at 2-5°C / min and then cool in the furnace.

[0080] Example 2

[0081] A modified ZTA composite ceramic spray granulation powder, the raw materials for its preparation include:

[0082] Multi-scale alumina is made by compounding nano-alumina coarse particles with a particle size of 5 μm, nano-alumina medium particles with a particle size of 2 μm, and nano-alumina fine particles with a particle size of 0.8 μm in a mass ratio of 6:2:1;

[0083] The modified nano ZrO2 after surface modification by silane coupling agent has a particle size of 50nm;

[0084] Nanocomposite powder, including nano-Cr2O3 and nano-MnO, wherein the mass ratio of nano-Cr2O3 to nano-MnO is 5:1;

[0085] Adhesive;

[0086] dispersants;

[0087] Among them, the mass ratio of multi-scale alumina, modified nano-ZrO2, nano-composite powder, binder and dispersant is 66.99:25:5:3:0.01.

[0088] A method for preparing a modified ZTA composite ceramic spray granulation powder comprises the following steps:

[0089] 1) Preparation of modified nano ZrO2:

[0090] Dissolve the silane coupling agent in anhydrous ethanol, add nano zirconium oxide, disperse it ultrasonically for 30 minutes, dry and activate it at 90℃ to obtain the desired modified nano ZrO2.

[0091] 2) The modified nano-ZrO2 and nano-alumina fine particles with a particle size of 0.8 μm were coated and compounded at the nanoscale by high-speed ball milling at a speed of 600 rpm and a mixing time of 2 h to form ZrO2@Al2O3 composite powder, which can solve the problem of nano-ZrO2 dispersion;

[0092] 3) The ZrO2@Al2O3 composite powder obtained in step 2) was first ball-milled with nano-alumina particles with a particle size of 2 μm and then coarse nano-alumina particles with a particle size of 5 μm were added and continued to be ball-milled and mixed evenly. The electron microscope image of the obtained product is shown in FIG. Figure 1 As shown, the nanocomposite powder is then added and ball milling is continued to mix uniformly to obtain a composite powder; by mixing the fine, medium and coarse nano-alumina particles in this order, the agglomeration of the nanoparticles is effectively avoided, which is beneficial to improving the uniformity of the particles and achieving the optimization of the porosity;

[0093] 4) The composite powder obtained in step 3) was mixed uniformly with deionized water and a dispersant (ammonium polyacrylate) by ball milling, and then a binder (PVA) was added and the mixture was mixed uniformly by ball milling at pH = 10;

[0094] 5) Spray granulation: The desired modified ZTA composite ceramic spray granulation powder can be obtained by using a spray drying method with the air inlet temperature controlled at 220°C, the outlet temperature at 100°C, and the atomization pressure at 0.6 MPa.

[0095] In step 4), after adding the nanocomposite powder, the mixture was first run at 250 rpm for 0.5 h to break the soft agglomerates, and then run at 380 rpm for 3 h to achieve nano-scale dispersion.

[0096] Application of a modified ZTA composite ceramic spray granulation powder in the preparation of a modified ZTA composite ceramic. The rest is the same as in Example 1.

[0097] Comparative Example 1

[0098] The difference between this comparative example and Example 1 is that this comparative example uses nano-alumina coarse particles with a particle size of 3 μm instead of multi-scale alumina, and the rest is the same as Example 1.

[0099] Comparative Example 2

[0100] The difference between this comparative example and Example 1 is that this comparative example uses commercially purchased nano-Cr2O3, does not utilize nano-Cr(OH)3 powder obtained by thermal decomposition, and does not contain nano-MnO. The rest is the same as Example 1.

[0101] Comparative Example 3

[0102] The difference between this comparative example and Example 1 is that this comparative example uses nano-Cr2O3 obtained by thermal decomposition of nano-Cr(OH)3 powder, without nano-MnO, and the rest is the same as Example 1.

[0103] Comparative Example 4

[0104] The difference between this comparative example and Example 1 is that this comparative example uses nano-MnO and no nano-Cr2O3, and the rest is the same as Example 1.

[0105] The spray granulation powders obtained in Example 1 and Comparative Examples 1-4 were subjected to performance tests, and the results are shown in Table 1.

[0106] Table 1

[0107]

[0108] As can be seen from Table 1, compared with Comparative Example 1 using a single nano-alumina, Example 1 uses three nano-alumina with different particle sizes, so that the spray-granulated powder prepared has higher flexural strength and tap density and lower sintering shrinkage, the sintering temperature can be reduced by 50-100°C, and the fracture toughness can be increased by ≥15%, indicating that the modified ZTA composite ceramic spray-granulated powder required by the present invention cannot be prepared by using nano-alumina with a single particle size, and three nano-alumina with different particle sizes must be used in synergy; comparing Comparative Examples 2-4 with Example 1, Example 1 uses the synergistic effect of nano-Cr2O3 and nano-MnO to make the spray-granulated powder have higher flexural strength and tap density and lower sintering shrinkage, and simultaneously achieve "strong grain boundaries" and "high density", indicating that the modified ZTA composite ceramic spray-granulated powder required by the present invention cannot be prepared by using single nano-Cr2O3 or nano-MnO, and nano-Cr2O3 and nano-MnO must be used in synergy.

[0109] Parts or structures not specifically described in the present invention may be adopted from existing technologies or existing products and will not be described in detail here. The above description is only an embodiment of the present invention and does not limit the scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification, or directly or indirectly applied to other related technical fields, are also included in the scope of patent protection of the present invention.

Claims

1. A modified ZTA composite ceramic spray granulation powder, characterized in that: The raw materials for its preparation include: Multi-scale alumina, including nano-alumina with at least two different particle sizes; Modified nano ZrO2; Nanocomposite powder, including nano-Cr2O3 and nano-MnO; Adhesive; Dispersant.

2. The modified ZTA composite ceramic spray granulation powder according to claim 1, characterized in that: The mass ratio of the multi-scale alumina, modified nano ZrO2, nano composite powder, binder and dispersant is (64.5-88.49): (10-25): (0.5-5): (1-5): (0.01-0.5).

3. The modified ZTA composite ceramic spray granulation powder according to claim 1, characterized in that: The multi-scale alumina is prepared by compounding three nano-alumina with different particle sizes.

4. The modified ZTA composite ceramic spray granulation powder according to claim 3, characterized in that: The multi-scale alumina is prepared by compounding nano alumina coarse particles with a particle size of 3-5 μm, nano alumina medium particles with a particle size of 1-2 μm, and nano alumina fine particles with a particle size of 0.3-0.8 μm in a mass ratio of (4-6): (2-4): (1-3).

5. The modified ZTA composite ceramic spray granulation powder according to claim 1, characterized in that: The modified nano ZrO2 is ZrO2 whose surface is modified by a silane coupling agent and has a particle size of 5-50 nm.

6. The modified ZTA composite ceramic spray granulation powder according to claim 1, characterized in that: The mass ratio of the nano-Cr2O3 to the nano-MnO is (1.5-5): (1-2).

7. The method for preparing a modified ZTA composite ceramic spray granulation powder according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) Preparation of modified nano ZrO2; 2) The modified nano-ZrO2 and nano-alumina fine particles with a particle size of 0.3-0.8 μm are subjected to nano-scale coating and compounding by high-speed ball milling at a speed of 300-600 rpm and a mixing time of 2-4 hours to form a ZrO2@Al2O3 composite powder; 3) ball-milling the ZrO2@Al2O3 composite powder obtained in step 2) with medium-sized nano-alumina particles with a particle size of 1-2 μm, then adding coarse nano-alumina particles with a particle size of 3-5 μm and continuing to ball-mill and mix evenly, and then adding the nano-composite powder and continuing to ball-mill and mix evenly to obtain a composite powder; 4) The composite powder obtained in step 3) is mixed uniformly with deionized water and a dispersant by ball milling, and then a binder is added and mixed uniformly by ball milling at a pH of 9-10; 5) Spray granulation: Control the inlet air temperature at 180-220°C, the outlet temperature at 90-100°C, and the atomization pressure at 0.3-0.6 MPa to obtain the desired modified ZTA composite ceramic spray granulation powder.

8. The method for preparing a modified ZTA composite ceramic spray granulation powder according to claim 7, characterized in that: In step 1), the preparation steps of the modified nano ZrO2 include: Dissolve the silane coupling agent in anhydrous ethanol, add nano zirconium oxide, disperse by ultrasonic for 30-60 minutes, dry and activate at 70-90℃ to obtain the desired modified nano ZrO2.

9. The method for preparing a modified ZTA composite ceramic spray granulation powder according to claim 7, characterized in that: In step 4), after adding the nanocomposite powder, the reactor is first operated at a speed of 150-250 rpm for 0.5-1 h, and then operated at a speed of 380-450 rpm for 2-3 h.

10. Use of the modified ZTA composite ceramic spray granulation powder according to any one of claims 1 to 6 in preparing modified ZTA composite ceramics.

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