Method for preparing magneto-optical ceramic powder and ceramic powder

Abstract

This invention discloses a method for preparing magneto-optical ceramic powder and the ceramic powder itself, wherein the preparation method follows Tb 3‑x A x Al 4.88‑y‑ z B y C z D 0.12 O 12 A stoichiometric metal ion mixed solution is prepared, wherein A is one of Ce, Pr, Nd, and Tm; B is one of Sc, Yb, Lu, or Y; C is one of Mg, Si, and Zr; and D is one of Ga and Gd; 0.02 ≤ x < 0.06, 0.735 ≤ y < 1.2, and 0.07 ≤ z < 0.1, and the total concentration of metal ions in the mixed solution is 1.5–1.9 M. The metal ion mixed solution is added dropwise to a precipitant solution containing a dispersant. During the addition, the precipitant solution is subjected to high-frequency ultrasonic vibration and stirring, and the mixture is thoroughly stirred to obtain a precipitate. After washing, drying, sieving, and debinding, the precipitate is obtained as terbium aluminum garnet-based magneto-optical transparent ceramic powder. The powder prepared by this invention has high sphericity, small particle size, good dispersibility, low ceramic porosity, high permeability, and excellent flexural strength and Vickers hardness.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically relating to a method for preparing magneto-optical ceramic powder and the ceramic powder itself. Background Technology

[0002] Magneto-optical materials have crucial applications in high-tech fields such as fiber optic communication, laser processing, and computers. In recent years, the development of high-power lasers has placed higher demands on the performance of magneto-optical materials, including high Verdet constants, high optical quality, large size, high thermal conductivity, and high laser damage threshold. Early commonly used magneto-optical materials were primarily magneto-optical glass and magneto-optical crystals. However, magneto-optical glass has low thermal conductivity, making it prone to thermal damage and unable to withstand high laser power, thus gradually failing to meet the requirements of magneto-optical devices. While magneto-optical crystals possess high thermal conductivity, their long growth cycle limits their size, failing to meet the demand for large-aperture magneto-optical elements in high-power lasers. In recent years, advancements in ceramic fabrication technology have made the transparency of ceramics a reality. Furthermore, with continuous technological improvements, the optical quality of transparent ceramics has been further enhanced, with optical performance even comparable to single crystals. Magneto-optical ceramics have emerged against this backdrop, becoming a novel type of magneto-optical material in recent years. Magneto-optical ceramics possess high thermal conductivity, high fracture toughness, good thermal shock resistance, and are readily available in large sizes. These performance advantages meet the performance requirements of high-power lasers for magneto-optical materials, making magneto-optical ceramics a promising candidate for application.

[0003] Terbium aluminum garnet (Tb3Al5O) 12 TAG (Transparent Magneto-Optical Material) exhibits high optical transmittance and a large Verdet constant in the visible and near-infrared bands, making it widely considered the most ideal magneto-optical material in this band. It is typically prepared from raw material oxides such as Tb₂O₃ and Al₂O₃. However, due to the non-uniform melting characteristics of TAG, crystal preparation is extremely difficult, thus limiting its widespread application. Ceramic preparation techniques can effectively avoid the non-uniform melting problem and maintain the excellent magneto-optical properties of TAG single crystals; therefore, TAG magneto-optical transparent ceramics have a promising future.

[0004] Therefore, in order to address the above-mentioned technical problems, it is necessary to provide a method for preparing magneto-optical ceramic powder and the ceramic powder itself. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing magneto-optical ceramic powder and the ceramic powder itself.

[0006] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution:

[0007] The preparation method of magneto-optical ceramic powder, according to Tb 3-x A x Al 4.88-y-z B y C z D 0.12 O 12 Prepare a stoichiometric solution of mixed metal ions (by weighing elemental oxides), wherein A is one of Ce, Pr, Nd, or Tm; B is one of Sc, Yb, Lu, or Y; C is one of Mg, Si, or Zr; and D is one of Ga or Gd; 0.02 ≤ x < 0.06, 0.735 ≤ y < 1.2, 0.07 ≤ z < 0.1, and the total concentration of metal ions in the mixed solution is 1.5-1.9 M; add the mixed solution dropwise (dropping rate 40-100 drops / m³). The terbium aluminum garnet (Mg), Si, and Zr are added dropwise to a precipitant solution containing a dispersant. During addition, the precipitant solution is subjected to high-frequency ultrasonic vibration and stirring to obtain a precipitate. The precipitate is then washed (3-6 times with deionized water and 1-4 times with anhydrous ethanol), dried (at 60-80℃ for 12-36 hours), sieved (the dried powder is passed through a 200-3000 mesh sieve), and debinded (held at 800-1300℃ for 2-4 hours in a first atmosphere) to obtain terbium aluminum garnet-based magneto-optical transparent ceramic powder. Mg, Si, and Zr are lattice-doped. Preferably, the first atmosphere used during debinding is air or a hydrogen-rich nitrogen atmosphere with a hydrogen content of 10-20 vol%.

[0008] In one or more embodiments of the present invention, the high-frequency ultrasonic oscillation in the first state is achieved with 15-30KHz ultrasound.

[0009] In one or more embodiments of the present invention, the ultrasonic power of the high-frequency ultrasonic oscillation is 60-100W.

[0010] In one or more embodiments of the present invention, the temperature during high-frequency ultrasonic oscillation in the first state is maintained at 10–45°C.

[0011] In one or more embodiments of the present invention, the stirring speed in the first state is 40 to 80 rpm.

[0012] In one or more embodiments of the present invention, the precipitant is at least one of NH4HCO3, ammonia, and urea.

[0013] In one or more embodiments of the present invention, the molar ratio of the concentration of the precipitant to aluminum ions in the precipitant solution is (1-3):1.

[0014] In one or more embodiments of the present invention, the dispersant is at least one of (NH4)2SO4, polyethyleneimine, ammonium polyacrylate, ammonium citrate, and polyethylene glycol.

[0015] In one or more embodiments of the present invention, Al in the dispersant and metal ion mixed solution 3+ The molar ratio is (0.1~5):1.

[0016] In one or more embodiments of the present invention, magneto-optical ceramic powder is prepared by the aforementioned magneto-optical ceramic powder preparation method.

[0017] Compared with the prior art, the magneto-optical ceramic powder preparation method and ceramic powder of the present invention produce powder with high sphericity, small particle size, and good dispersibility. The porosity of the sintered ceramic is as low as 0.01%. It has high transmittance in the visible-near infrared band (633nm-1380nm), and excellent bending strength and Vickers hardness, which fully meet the performance requirements of high-power lasers for magneto-optical ceramics. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a SEM image of a ceramic sample in one embodiment of the present invention;

[0020] Figure 2 This is a transmittance curve of a ceramic sample in one embodiment of the present invention;

[0021] Figure 3 This is a PSD image of the raw material of a ceramic sample in one embodiment of the present invention;

[0022] Figure 4 This is a SEM image of a ceramic sample in one embodiment of the present invention;

[0023] Figure 5 This is a transmittance curve of a ceramic sample in one embodiment of the present invention;

[0024] Figure 6 This is a PSD image of the raw material of a ceramic sample in one embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments disclosed herein. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0026] Example 1

[0027] In this embodiment, the magneto-optical ceramic powder is prepared as follows:

[0028] According to Tb soluble metal salts 2.98 A 0.02 Al 4.075 B 0.735 C 0.07 D 0.12 O 12 A stoichiometric solution of metal ions is prepared, wherein A is Ce; B is Sc; C is Mg; and D is Ga; and the total concentration of metal ions in the solution is 1.5 M.

[0029] Prepare a precipitant solution containing a dispersant, wherein the precipitant is NH4HCO3 and the dispersant is (NH4)2SO4.

[0030] The precipitate solution was prepared by adding a mixed solution of metal ions dropwise to the precipitant solution in its first state at a rate of 40 drops / min, using 15 kHz ultrasound at a power of 60 W, maintaining a temperature of 10℃, and stirring at a speed of 40 rpm. At the end of the addition, the molar ratio of the precipitant concentration to aluminum ions was 1:1; the concentration of Al in the dispersant and metal ion mixed solution was... 3+ The molar ratio is 0.1:1.

[0031] After standing for 1 hour, the precipitate was washed (three times with deionized water and once with anhydrous ethanol), dried (drying at 60℃ for 12 hours), sieved (the dried powder was passed through a 200-mesh sieve), and debinded (held at 800℃ in air for 2 hours) to obtain terbium aluminum garnet-based magneto-optical transparent ceramic powder.

[0032] The powder sample in this embodiment was tested, such as... Figure 3 The sample shown has the following particle sizes: D10: 1.33 μm; D50: 2.57 μm; D90: 5.18 μm, and a tap density of 4.0 g / cm³. 3 The shape factor F of the powder sample particles is 0.94.

[0033] It should be noted that F = 4πA / (P) 2), where A is the projected area of ​​the particle in the TEM image of the sample, and P is the perimeter of the particle, and the same applies below.

[0034] In this embodiment, the powder was dry-pressed, then cold isostatically pressed, followed by hot pressing sintering. The hot pressing sintering temperature was 1680℃, the holding time was 10 hours, and a pressure of 100 MPa was applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing was performed to obtain magneto-optically transparent ceramic. Figure 1 and 2 As shown, the obtained magneto-optically transparent ceramic has a porosity of <0.02%, and its transmittance reaches 79.8% at 1380 nm, 78.9% at 1064 nm, and 69.3% at 633 nm. The flexural strength of the ceramic is tested to be 236.5±16.1 MPa, and the Vickers hardness (HV) is 12.8±0.1 GPa.

[0035] Example 2

[0036] The only difference between this embodiment and Embodiment 1 is that the adhesive removal is carried out at 800°C for 2 hours in a hydrogen-rich nitrogen atmosphere with a hydrogen content of 13 vol.%.

[0037] The powder sample in this embodiment was tested, such as... Figure 6 As shown, the sample particle sizes meet the following requirements: D10: 1.32 μm; D50: 2.49 μm; D90: 4.88 μm, and the tap density is 4.1 g / cm³. 3 The shape factor F of the powder sample particles is 0.98.

[0038] In this embodiment, the powder was dry-pressed, then cold isostatically pressed, followed by hot pressing sintering. The hot pressing sintering temperature was 1680℃, the holding time was 10 hours, and a pressure of 100 MPa was applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing was performed to obtain magneto-optically transparent ceramic. Figure 4 and 5 As shown, the obtained magneto-optically transparent ceramic has a porosity of <0.01%, and its transmittance reaches 84.3% at 1380 nm, 84.6% at 1064 nm, and 81.9% at 633 nm. The flexural strength of the ceramic is tested to be 249.4±14.2 MPa, and the Vickers hardness (HV) is 13.8±0.3 GPa.

[0039] Example 3

[0040] The only difference between this embodiment and Embodiment 1 is that the dropping rate of the metal ion mixed solution is 70 drops / min.

[0041] The powder sample in this embodiment was tested and the particle size met the following requirements: D10: 1.38 μm; D50: 2.8 μm; D90: 6 μm, and the tap density was 3.8 g / cm³. 3 The shape factor of the powder sample particles is F=0.89.

[0042] The powder from this embodiment was dry-pressed, then cold-isostatically pressed, and subsequently hot-pressed and sintered at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.05%, a transmittance of 78.3% at 1380 nm, 78.4% at 1064 nm, and 70.3% at 633 nm. The flexural strength of the ceramic was tested to be 223.5 ± 18.1 MPa, and the Vickers hardness (HV) was 11.8 ± 0.2 GPa.

[0043] Example 4

[0044] The only difference between this embodiment and Embodiment 1 is that the temperature is maintained at 25°C during ultrasound.

[0045] The powder sample in this embodiment was tested and the particle size met the following requirements: D10: 1.42 μm; D50: 3.5 μm; D90: 7.8 μm, and the tap density was 3.5 g / cm³. 3 The shape factor of the powder sample particles is F=0.89.

[0046] The powder from this embodiment was dry-pressed, then cold-isostatically pressed, and subsequently hot-pressed and sintered at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.08%, a transmittance of 78.4% at 1380 nm, 77.9% at 1064 nm, and 69.1% at 633 nm. The flexural strength of the ceramic was tested to be 216.2 ± 17.1 MPa, and the Vickers hardness (HV) was 11.5 ± 0.2 GPa.

[0047] Example 5

[0048] The only difference between this embodiment and Embodiment 1 is that the stirring speed is 60 rpm.

[0049] The powder sample in this embodiment was tested and the particle size met the following requirements: D10: 1.6 μm; D50: 2.51 μm; D90: 5.1 μm, and the tap density was 3.7 g / cm³. 3 The shape factor F of the powder sample particles is 0.85.

[0050] The powder from this embodiment was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering. The hot-pressing sintering temperature was 1680℃, and the holding time was 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.02%, a transmittance of 68.8% at 1380 nm, 67.6% at 1064 nm, and 65.2% at 633 nm. The flexural strength of the ceramic was tested to be 239.5 ± 16.2 MPa, and the Vickers hardness (HV) was 12.7 ± 0.1 GPa.

[0051] Example 6

[0052] The only difference between this embodiment and Embodiment 1 is that the ultrasonic power is 70W.

[0053] The powder sample in this embodiment was tested and the particle size met the following requirements: D10: 1.8 μm; D50: 2.54 μm; D90: 5.7 μm, and the tap density was 4.1 g / cm³. 3 The shape factor F of the powder sample particles is 0.94.

[0054] The powder from this embodiment was dry-pressed, then cold-isostatically pressed, and subsequently hot-pressed and sintered at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.02%, a transmittance of 79.9% at 1380 nm, 78.7% at 1064 nm, and 69.2% at 633 nm. The flexural strength of the ceramic was tested to be 236.6 ± 16.1 MPa, and the Vickers hardness (HV) was 12.7 ± 0.1 GPa.

[0055] Example 7

[0056] The only difference between this embodiment and Embodiment 1 is that the Al in the dispersant and metal ion mixed solution... 3+ The molar ratio is 0.15:1.

[0057] The powder sample in this embodiment was tested and the particle size met the following requirements: D10: 1.61 μm; D50: 2.6 μm; D90: 6.5 μm, and the tap density was 3.9 g / cm³. 3 The shape factor F of the powder sample particles is 0.88.

[0058] The powder from this embodiment was dry-pressed, then cold-isostatically pressed, and subsequently hot-pressed and sintered at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.08%, a transmittance of 76.9% at 1380 nm, 75.8% at 1064 nm, and 69.8% at 633 nm. The flexural strength of the ceramic was tested to be 230.2 ± 16.3 MPa, and the Vickers hardness (HV) was 12.2 ± 0.1 GPa.

[0059] Example 8

[0060] The only difference between this embodiment and Example 1 is that the molar ratio of the concentration of the precipitant to that of aluminum ions is 1.3:1.

[0061] The powder sample in this embodiment was tested and the particle size met the following requirements: D10: 1.5 μm; D50: 3.4 μm; D90: 7.8 μm, and the tap density was 3.5 g / cm³. 3 The shape factor of the powder sample particles is F=0.79.

[0062] The powder from this embodiment was dry-pressed, then cold-isostatically pressed, and subsequently hot-pressed and sintered at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.15%, a transmittance of 69.2% at 1380 nm, 68.3% at 1064 nm, and 65.6% at 633 nm. The flexural strength of the ceramic was tested to be 237.3 ± 16.1 MPa, and the Vickers hardness (HV) was 12.6 ± 0.1 GPa.

[0063] Comparative Example 1

[0064] The only difference between this comparative example and Example 2 is that the glue removal was carried out at 800°C for 2 hours in a hydrogen-rich nitrogen atmosphere with a hydrogen content of 8 vol.%.

[0065] The powder samples in this comparative example were tested and found to have the following particle sizes: D10: 1.8 μm; D50: 3.6 μm; D90: 8.1 μm, and a tap density of 3.2 g / cm³. 3 The shape factor of the powder sample particles is F=0.82.

[0066] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.10%, a transmittance of 63.5% at 1380 nm, 61.7% at 1064 nm, and 60.2% at 633 nm. The flexural strength of the ceramic was tested to be 219.5 ± 13.1 MPa, and the Vickers hardness (HV) was 12.3 ± 0.1 GPa.

[0067] Comparative Example 2

[0068] The only difference between this comparative example and Example 2 is that the glue removal was carried out at 800°C for 2 hours in a hydrogen-rich nitrogen atmosphere with a hydrogen content of 21 vol.%.

[0069] The powder samples in this comparative example were tested and found to have the following particle sizes: D10: 2.1 μm; D50: 4.5 μm; D90: 5.3 μm, and a tap density of 3.3 g / cm³. 3 The shape factor F of the powder sample particles is 0.78.

[0070] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.22%, a transmittance of 58.6% at 1380 nm, 57.2% at 1064 nm, and 45.1% at 633 nm. The flexural strength of the ceramic was tested to be 234.5 ± 17.2 MPa, and the Vickers hardness (HV) was 12.5 ± 0.2 GPa.

[0071] Comparative Example 3

[0072] The only difference between this comparative example and Example 2 is that the dropping rate of the metal ion mixed solution is 30 drops / min.

[0073] The powder sample in this comparative example was tested, and the particle size met the following requirements: D10: 1.6 μm; D50: 3.6 μm; D90: 8.1 μm, and the tap density was 3.4 g / cm³. 3 The shape factor of the powder sample particles is F=0.83.

[0074] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.08%, a transmittance of 62.6% at 1380 nm, 61.3% at 1064 nm, and 60.5% at 633 nm. The flexural strength of the ceramic was tested to be 228.3 ± 12.2 MPa, and the Vickers hardness (HV) was 12.3 ± 0.1 GPa.

[0075] Comparative Example 4

[0076] The only difference between this comparative example and Example 2 is that the temperature was maintained at 8°C during ultrasound.

[0077] The powder samples in this comparative example were tested and found to have the following particle sizes: D10: 0.9 μm; D50: 3.6 μm; D90: 6.1 μm, and a tap density of 3.9 g / cm³. 3 The shape factor of the powder sample particles is F=0.89.

[0078] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.07%, a transmittance of 69.1% at 1380 nm, 68.3% at 1064 nm, and 66.1% at 633 nm. The flexural strength of the ceramic was tested to be 223.5 ± 11.2 MPa, and the Vickers hardness (HV) was 11.7 ± 0.2 GPa.

[0079] Comparative Example 5

[0080] The only difference between this comparative example and Example 2 is that the stirring speed is 30 rpm.

[0081] The powder samples in this comparative example were tested and found to have the following particle sizes: D10: 1.6 μm; D50: 3.6 μm; D90: 8.1 μm, and a tap density of 3.5 g / cm³. 3 The shape factor of the powder sample particles is F=0.91.

[0082] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.16%, a transmittance of 64.1% at 1380 nm, 63.4% at 1064 nm, and 62.3% at 633 nm. The flexural strength of the ceramic was tested to be 229.5 ± 17.2 MPa, and the Vickers hardness (HV) was 11.6 ± 0.1 GPa.

[0083] Comparative Example 6

[0084] The only difference between this comparative example and Example 2 is that the Al in the dispersant and metal ion mixed solution... 3+ The molar ratio is 0.05:1.

[0085] The powder samples in this comparative example were tested and found to have the following particle sizes: D10: 0.4 μm; D50: 2.1 μm; D90: 4.1 μm, and a tap density of 3.3 g / cm³. 3The shape factor F of the powder sample particles is 0.90.

[0086] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.19%, a transmittance of 53.1% at 1380 nm, 52.3% at 1064 nm, and 48.1% at 633 nm. The flexural strength of the ceramic was tested to be 230.5 ± 16.7 MPa, and the Vickers hardness (HV) was 12.0 ± 0.1 GPa.

[0087] Comparative Example 7

[0088] The only difference between this comparative example and Example 2 is that the molar ratio of the precipitant concentration to aluminum ions is 0.9:1.

[0089] The powder samples in this comparative example were tested and found to have the following particle sizes: D10: 0.9 μm; D50: 4.3 μm; D90: 9.1 μm, and a tap density of 3.7 g / cm³. 3 The shape factor F of the powder sample particles is 0.85.

[0090] The comparative example powder was dry-pressed, then cold-isostatically pressed, followed by hot-pressing sintering at 1680℃ for 10 hours, with a pressure of 100 MPa applied to the green body. The pre-sintered ceramic sample was then subjected to hot isostatic pressing (HIP) sintering at 1600℃ for 3 hours, with a furnace gas pressure of 200 MPa. Finally, double-sided polishing yielded a magneto-optically transparent ceramic. The obtained magneto-optically transparent ceramic had a porosity of <0.21%, a transmittance of 52.4% at 1380 nm, 47.3% at 1064 nm, and 45.5% at 633 nm. The flexural strength of the ceramic was tested to be 213.5 ± 16.2 MPa, and the Vickers hardness (HV) was 10.6 ± 0.1 GPa.

[0091]

[0092] In summary, the present invention offers the following technical advantages compared to existing technologies:

[0093] First, comparing Example 1 and Example 2 verifies the following conclusions: Powder properties: In Example 2, the powder D10 decreased from 0.8 μm to 0.6 μm, and the tap density increased from 4.0 g / cm³.3 Increased to 4.1 g / cm 3 , the shape factor F increased from 0.94 to 0.98, indicating that hydrogen-rich debinding can refine the powder particle size, improve the particle sphericity, reduce the pores between particles, increase the tapped density of the powder, and lay a foundation for the subsequent sintering to prepare high-density ceramics. In Example 2, the porosity of the ceramic decreased from 0.02% to 0.01%, the transmittance at 1380 nm increased from 79.8% to 84.3%, the transmittance at 1064 nm increased from 78.9% to 84.6%, the transmittance at 633 nm increased from 69.3% to 81.9%, the flexural strength increased from 236.5 ± 16.1 MPa to 249.4 ± 14.2 MPa, and the Vickers hardness increased from 12.8 ± 0.1 GPa to 13.8 ± 0.3 GPa. The core reason is that the 13 v / v% hydrogen-rich nitrogen atmosphere can effectively reduce the surface defects of the powder, reduce the porosity at the grain boundaries during sintering, increase the density of the ceramic, and the increase in density simultaneously realizes the dual improvement of optical transmittance and mechanical properties.

[0094] Furthermore, by comparing Comparative Example 1 (8 v / v% hydrogen-rich) and Comparative Example 2 (21 v / v% hydrogen-rich) with Example 2, the preferred range of hydrogen-rich concentration was verified: when the hydrogen content was 8 v / v%, the powder particle size coarsened (D50 = 3.6 μm), and the tapped density decreased to 3.2 g / cm 3 , and the transmittance of the ceramic decreased significantly (only 63.5% at 1380 nm). The reason is that the hydrogen concentration is insufficient to effectively reduce the powder defects, the sintering activity of the powder is low, and the porosity after sintering is relatively high. When the hydrogen content was 21 v / v%, abnormal data of D90 < D50 appeared, and the porosity of the ceramic increased to 0.22%, and the transmittance at 633 nm was only 45.1%. The reason is that the hydrogen concentration is too high, and excessive hydrogen bubbles are generated during the debinding process, adsorbed on the surface of the powder to form micropores, and the micropores cannot be eliminated after sintering, seriously reducing the optical properties of the ceramic.

[0095] Furthermore, by comparing Example 1 and Example 3, after the dropping rate was increased, the D50 of the powder increased from 2.3 μm to 2.8 μm, and the tapped density decreased from 4.0 g / cm 3 to 3.8 g / cm 3 , the shape factor F decreased from 0.94 to 0.89, and the porosity of the ceramic increased to 0.05%, and the transmittance decreased slightly. It shows that the low dropping rate of 40 drops / min allows the metal ions to react fully with the precipitant, generating spherical and small-sized precipitate particles; too fast dropping rate leads to too high local concentration, rapid growth of precipitate particles with irregular morphology, aggravated agglomeration phenomenon, and subsequent decline in the sintering performance of the ceramic. In Comparative Example 3, the dropping rate was 30 drops / min (lower than 40 drops / min), and the transmittance of the ceramic was only 62.6%, indicating that too low dropping rate will lead to too slow reaction rate, and the precipitate particles are prone to static agglomeration, also reducing the powder properties.

[0096] Furthermore, comparing Example 1 and Example 4, after increasing the ultrasonic temperature, the powder D50 increased from 2.3 μm to 3.5 μm, while the tap density decreased to 3.5 g / cm³. 3 The ceramic porosity increased to 0.08%, while the transmittance decreased slightly. This indicates that low-temperature ultrasound at 10℃ can reduce the precipitation reaction rate, allowing particles to grow slowly and inhibiting particle agglomeration. Higher temperatures accelerate the precipitation reaction rate, resulting in coarser particle sizes, and the ultrasonic cavitation effect weakens, failing to effectively break up agglomerates. In Comparative Example 4, with an ultrasonic temperature of 8℃ (below 10℃), the ceramic transmittance was 69.1%, indicating that excessively low temperatures lead to decreased precipitant solubility, incomplete reaction, and increased powder impurity content.

[0097] Furthermore, comparing Example 1 and Example 5, after increasing the stirring speed, the powder D50 decreased to 2.1 μm, but the shape factor F decreased to 0.85, the ceramic porosity surged to 0.12%, and the transmittance decreased significantly (only 68.8% at 1380 nm). Technical effect: While high-speed stirring at 60 rpm can refine the precipitated particles, it destroys the spherical morphology of the particles, making them irregular. Irregular particles have large gaps during sintering, making it difficult for pores to escape, resulting in a significant decrease in ceramic density and transmittance. Low-speed stirring at 40 rpm can ensure particle sphericity and achieve close particle packing. In Comparative Example 5, with a stirring speed of 30 rpm (below 40 rpm), the powder agglomeration was severe (D50 = 3.6 μm), and the ceramic porosity was 0.16%, indicating that too low a stirring speed cannot achieve uniform mixing of the solution, resulting in uneven local precipitation.

[0098] Furthermore, comparing Example 1 and Example 6, after increasing the ultrasonic power to 70W, the powder properties (D50=2.4μm, tap density 4.1g / cm³) were improved. 3 The properties of the powder (F=0.94) and ceramics (porosity 0.02%, transmittance 79.9%) are basically the same as those in Example 1. Technical effect: 60-100W is the effective range of ultrasonic power. The cavitation effect within this power range can effectively break up agglomerates without damaging the particle morphology. The powder and ceramic properties remain stable, providing tolerance for the selection of process parameters.

[0099] Furthermore, comparing Example 1 and Example 7, after increasing the dispersant ratio, the powder D50 increased from 2.3 μm to 2.6 μm, and the tap density decreased to 3.9 g / cm³. 3The ceramic porosity increased to 0.08%, and the permeability decreased. Technical effect: 0.1:1 is the optimal dispersant ratio, which can form effective steric hindrance on the particle surface and prevent agglomeration; excessive dispersant will adsorb onto the particle surface to form an organic film. During the debinding process, the organic film decomposes and generates gas, forming micropores inside the powder and reducing the sintering activity of the powder. Comparative Example 6, with a dispersant ratio of 0.05:1 (lower than 0.1:1), achieved a powder tap density of 4.3 g / cm³. 3 However, the ceramic porosity is 0.19% and the permeability is only 53.1%. This is because the dispersant is insufficient, the precipitated particles are severely agglomerated, and large-sized pores are formed between the agglomerates after sintering, which cannot be eliminated.

[0100] Furthermore, through Examples 1 and 8, after increasing the precipitant ratio, the powder D50 increased from 2.3 μm to 3.4 μm, the shape factor F decreased to 0.79, the ceramic porosity increased to 0.15%, and the transmittance decreased significantly. Technical effect: A 1:1 precipitant ratio ensures complete precipitation of metal ions without causing excessively high solution alkalinity; excessive precipitant increases solution alkalinity, causes rapid growth of precipitated particles with irregular morphology, and introduces excessive impurity ions, forming impurity phases after debinding. In Comparative Example 7, with a precipitant ratio of 0.9:1 (lower than 1:1), metal ion precipitation was incomplete, the powder D50 reached 4.3 μm, the ceramic porosity was 0.21%, the transmittance was only 52.4%, and the flexural strength decreased to 213.5 ± 16.2 MPa, the lowest among all cases, indicating that insufficient precipitant is a significant factor affecting ceramic performance.

[0101] Based on the performance data of all embodiments and comparative examples, Example 2 is the optimal process scheme. The powder prepared by this process has high sphericity, small particle size, and good dispersibility. The porosity of the sintered ceramic is as low as 0.01%. It has high transmittance in the visible-near infrared band (633nm-1380nm), and excellent bending strength and Vickers hardness, which fully meet the performance requirements of high-power lasers for magneto-optical ceramics.

[0102] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0103] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing magneto-optical ceramic powder, characterized in that, According to Tb 3-x A x Al 4.88-y-z B y C z D 0.12 O 12 A stoichiometric metal ion mixed solution is prepared, wherein A is one of Ce, Pr, Nd, and Tm; B is one of Sc, Yb, Lu, or Y; C is one of Mg, Si, and Zr; and D is one of Ga and Gd; 0.02 ≤ x < 0.06, 0.735 ≤ y < 1.2, and 0.07 ≤ z < 0.1, and the total concentration of metal ions in the metal ion mixed solution is 1.5-1.9 M; A mixed solution of metal ions is added dropwise to a precipitant solution containing a dispersant. During the dropwise addition, the precipitant solution is in a first state of high-frequency ultrasonic oscillation and stirring, and the precipitate is obtained by thorough stirring. After washing, drying, sieving, and debinding the precipitate, the terbium aluminum garnet-based magneto-optical transparent ceramic powder is obtained.

2. The method for preparing magneto-optical ceramic powder according to claim 1, characterized in that, In the first state, the high-frequency ultrasonic oscillation is achieved using 15-30KHz ultrasound.

3. The method for preparing magneto-optical ceramic powder according to claim 2, characterized in that, The ultrasonic power of the high-frequency ultrasonic oscillation is 60-100W.

4. The method for preparing magneto-optical ceramic powder according to claim 1, characterized in that, In the first state, the temperature during high-frequency ultrasonic oscillation is maintained at 10–45°C.

5. The method for preparing magneto-optical ceramic powder according to claim 1, characterized in that, The stirring speed in the first state is 40-80 rpm.

6. The method for preparing magneto-optical ceramic powder according to claim 1, characterized in that, The precipitant is at least one of NH4HCO3, ammonia, and urea.

7. The method for preparing magneto-optical ceramic powder according to claim 6, characterized in that, The molar ratio of the precipitant concentration to aluminum ions in the precipitant solution is (1-3):

1.

8. The method for preparing magneto-optical ceramic powder according to claim 1, characterized in that, The dispersant is at least one of (NH4)2SO4, polyethyleneimine, ammonium polyacrylate, ammonium citrate, and polyethylene glycol.

9. The method for preparing magneto-optical ceramic powder according to claim 1, characterized in that, The dispersant and metal ion mixed solution contains Al 3+ The molar ratio is (0.1~5):

1.

10. Magneto-optical ceramic powder, prepared by any one of the magneto-optical ceramic powder preparation methods according to claims 1-9.

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