A transparent ceramic resistant to laser damage and a method of making the same

Abstract

The application discloses transparent ceramic resistant to laser damage and a preparation method thereof, and the specific steps of the preparation method are as follows: powder mixing: adding LuAG ceramic powder, commercial phase reinforcing particles, anhydrous ethanol and high-purity alumina balls into a nylon ball mill jar, and using a planetary ball mill to mill to obtain slurry; drying and sieving: after the powder is fully mixed and uniformly distributed, the milled slurry is placed in an oven for drying, and then is sieved through a 100-200 mesh nylon screen to obtain uniform powder; calcining: the powder is placed in a crucible for calcining to remove organic impurities introduced in the milling process; dry pressing: the calcined powder is dry pressed under pressure to obtain a green body, and cold isostatic pressing is further performed to improve the density of the green body; hot isostatic pressing: the prepared green body is pre-fired in an air atmosphere, and then is subjected to hot isostatic pressing treatment in an argon atmosphere to eliminate residual pores; double-side polishing: the obtained green body is double-side polished to 3-6 mm to obtain LuAG transparent ceramic with a high laser damage threshold.

Description

Technical Field

[0001] This invention relates to the field of transparent ceramics technology, and in particular to a transparent ceramic resistant to laser damage and its preparation method. Background Technology

[0002] Transparent ceramics, as a new generation of solid-state laser materials, possess unparalleled advantages over laser crystals and glass, and represent a paradigm of integrated structure and function in the field of ceramic materials research. Compared to single crystals and glass, transparent ceramics offer significant advantages, including feasible high doping concentrations, flexible dimensions, composite structures, and short manufacturing times. An increasing number of transparent ceramic materials are being fabricated for use in laser systems; for example, the DiPOLE100 at Rutherford Appleton Laboratories in the UK and Hamamatsu Photonics in Japan both utilize transparent ceramics as gain media.

[0003] However, transparent ceramics exhibit a lower laser damage threshold compared to laser crystals, glasses, and thin films, and research on their laser damage is relatively limited. This is because, firstly, research on transparent ceramics as laser gain media started relatively late; secondly, as polycrystalline materials, transparent ceramics inevitably involve impurities and defects such as grain boundaries, micropores, and second phases during laser interaction, making the laser damage process and mechanism of transparent ceramics more complex and difficult to systematically and deeply explain and analyze. With the increasing application of transparent ceramics as laser gain media in various lasers, exploring transparent ceramics with high laser damage thresholds and their preparation methods has become increasingly urgent.

[0004] However, no methods for exploring ways to improve the damage threshold of transparent ceramics have been reported yet. But by combining the polycrystalline material properties of transparent ceramics, it is hoped that phase-reinforcing particles can be used to improve the laser damage threshold while ensuring the transmittance of transparent ceramics. Summary of the Invention

[0005] Technical problem solved: This invention solves the technical problem that existing transparent ceramics, represented by lutetium aluminum garnet system transparent laser ceramics, have low laser damage thresholds and are difficult to apply to high-energy, high-power lasers. It provides a laser-damage-resistant transparent ceramic and its preparation method. The micropores, grain boundaries and other structural defects contained in the transparent ceramic are more likely to cause light scattering and absorption when irradiated by laser, resulting in the concentration of thermal stress and thus laser damage.

[0006] Technical solution: The present invention provides a method for preparing a laser-damage-resistant transparent ceramic, which specifically includes the following steps:

[0007] Step 1, powder mixing: Add lutetium aluminum garnet ceramic powder, commercial phase-reinforcing particles, anhydrous ethanol and high-purity alumina balls into a nylon ball mill jar, and ball mill using a planetary ball mill to obtain a slurry;

[0008] The second step is drying and sieving: After the powder is fully mixed, the slurry after ball milling is placed in an oven to dry, and then passed through a 100-200 mesh nylon sieve to obtain uniform powder.

[0009] The third step is calcination: the powder is placed in a crucible and calcined to remove organic impurities introduced during the ball milling process;

[0010] The fourth step is dry pressing: the calcined powder is dry pressed under pressure to obtain a green blank, and then cold isostatic pressing is used to further increase the density of the green blank.

[0011] Step 5, hot isostatic pressing: After the prepared green blank is pre-fired in an air atmosphere, it is then hot isostatically pressed in an argon atmosphere to eliminate residual porosity.

[0012] Step 6, double-sided polishing: Polish the transparent ceramic obtained by hot isostatic pressing to 3-6mm on both sides to obtain lutetium aluminum garnet transparent ceramic with high laser damage threshold.

[0013] Preferably, the commercially available phase-reinforcing particles in the first step are one or more of the following: zirconium oxide (ZrO2) particles, strontium borate (SrB4O7) particles, boron nitride (BN) particles, and silicon carbide (SiC) particles.

[0014] Preferably, in the first step, the mass ratio of lutetium aluminum garnet ceramic powder, commercial phase-reinforcing particles, anhydrous ethanol, and high-purity alumina balls is 1.0:0.05-0.15:2.5:5.0; and the ball milling speed is 200-300 r·min. -1 The ball milling time is 10-18 hours.

[0015] Preferably, the drying temperature in the second step is 60-75℃ and the drying time is 15-20h.

[0016] Preferably, the calcination temperature in the third step is 750-850℃, and the calcination time is 5-9h.

[0017] Preferably, in the fourth step, the dry pressing pressure is 15-25 MPa, the cold isostatic pressing pressure is 200-300 MPa, and the cold isostatic pressing time is 5-10 min.

[0018] Preferably, in the fifth step of hot isostatic pressing, the pre-firing temperature is 1400-1600℃, the pre-firing time is 6.5-10h, the argon atmosphere is 1500-1800℃ and 180-220MPa, and the hot isostatic pressing treatment time is 2-6h.

[0019] Preferably, in the sixth step, the transparent ceramic is polished to 3mm on both sides.

[0020] This application also discloses laser-damage-resistant transparent ceramics prepared by any of the above-mentioned methods.

[0021] This application explains the principle of a laser-damage-resistant transparent ceramic and its preparation method. By using an appropriate amount of doped micro / nano particles, an interfacial buffer layer can be formed, slowing the propagation of laser energy into the material's interior. When a laser strikes the surface of the transparent ceramic, the particles can absorb the laser energy and disperse heat, thereby reducing energy accumulation within the material and minimizing the risk of laser damage. Simultaneously, the presence of micro / nano particles can alter the stress distribution of the transparent ceramic. Under strong laser irradiation, the material's interior is subjected to stress and thermal stress, leading to stress concentration and damage. Micro / nano particles can act as stress dispersers, reducing stress concentration and thus increasing the material's laser damage threshold. This solves the problem of generally low laser damage thresholds in existing transparent ceramics while ensuring that transmittance is not significantly reduced.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention relates to a transparent ceramic resistant to laser damage and its preparation method. The lutetium aluminum garnet transparent ceramic resistant to laser damage has a simple preparation process and effectively ensures transmittance and mechanical properties.

[0024] 2. The present invention provides a transparent ceramic resistant to laser damage and its preparation method. Since the selected phase reinforcement particles have high hardness, high melting point and good thermal conductivity, they can be effectively dispersed in the ceramic matrix, thereby improving the uniformity and optical quality of the material.

[0025] 3. The present invention provides a transparent ceramic resistant to laser damage and its preparation method, wherein transparent oxide particles can increase the toughness and crack resistance of the material, thereby improving the laser damage threshold;

[0026] 4. The presence of the selected micro / nano particles can alter the stress distribution of transparent ceramics. Under the influence of strong laser light, the material is subjected to stress and thermal stress, leading to stress concentration and damage. Micro / nano particles can act as stress dispersers, reducing stress concentration and thus increasing the laser damage threshold of the material.

[0027] 5. The laser-induced damage threshold (LIDT) of the samples was rigorously tested according to the international standard ISO 11254 using a 1-on-1 method until damage to the emitted surface was observed on the imaging CCD. During the test, at least 10 sites were irradiated at each fluence level. Each site visible as damaged under an optical microscope was considered a damage point. The damage probability was calculated based on the percentage of damage points. Damage probability maps at different fluence levels were plotted. The zero-probability laser damage threshold, represented by the intersection of the curve and the x-axis, was considered the damage probability. In this application, the damage threshold without reinforcing particles was 4.2 J / cm². 2 The concentration containing reinforcing particles is 6.5 J / cm³. 2 . Attached Figure Description

[0028] Figure 1 This is a comparison chart of the transmittance of transparent ceramics containing phase-reinforcing particles and transparent ceramics without phase-reinforcing particles in Embodiment 1 of this application;

[0029] Figure 2 This is a comparison chart of the damage thresholds of transparent ceramics containing phase-reinforcing particles and transparent ceramics without phase-reinforcing particles in Embodiment 1 of this application;

[0030] Figure 3 The image shows a comparison of the grain morphology of the transparent ceramic containing phase-reinforcing particles and the transparent ceramic without phase-reinforcing particles after damage, captured by scanning electron microscopy in Embodiment 1 of this application. Detailed Implementation

[0031] Referring to the accompanying drawings illustrating embodiments of the invention, the invention will be described in more detail below. However, the invention can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are presented to achieve a full and complete disclosure and to enable those skilled in the art to fully understand the scope of the invention. In these drawings, the dimensions and relative dimensions of layers and regions may be enlarged for clarity.

[0032] This invention employs appropriately doped micro / nano particles to reinforce the material, slowing the propagation of laser energy into the interior. Simultaneously, the particles absorb laser energy and disperse heat, reducing energy accumulation within the material and minimizing the risk of laser damage. Furthermore, the presence of these micro / nano particles alters the stress distribution of the transparent ceramic, thereby increasing its laser damage threshold. This solves the problem of generally low laser damage thresholds in existing transparent ceramics while maintaining a minimal reduction in transmittance.

[0033] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0034] Example 1:

[0035] A method for preparing a laser-damage-resistant transparent ceramic, characterized by comprising the following steps:

[0036] Step 1, Powder Mixing: Lutetium aluminum garnet ceramic powder, zirconium oxide (ZrO2) particles, anhydrous ethanol, and high-purity alumina balls are added to a nylon ball mill jar in a mass ratio of 1.0:0.1:2.5:5.0. The mixture is then ball-milled using a planetary ball mill at a speed of 300 r / min. -1 The ball milling time was 18 hours to obtain a slurry;

[0037] The second step is drying and sieving: After the powder is fully mixed, the slurry after ball milling is placed in an oven to dry at a temperature of 75°C for 15 hours. Then, it is passed through a 150-mesh nylon sieve to obtain uniform powder.

[0038] The third step is calcination: the powder is placed in a crucible and calcined at 785℃ for 9 hours. This removes organic impurities introduced during the ball milling process.

[0039] The fourth step is dry pressing: the calcined powder is dry pressed at a pressure of 125 MPa to obtain a green blank, and then cold isostatic pressing is used to further increase the density of the green blank. The cold isostatic pressing pressure is 300 MPa and the cold isostatic pressing time is 10 min.

[0040] Step 5, hot isostatic pressing: After the prepared green blank is pre-fired in an air atmosphere, it is then hot isostatically pressed in an argon atmosphere to eliminate residual porosity; the pre-fired temperature is 1500℃, the pre-fired time is 7h, the argon atmosphere is 1700℃ and 220MPa, and the hot isostatic pressing time is 6h.

[0041] Step 6, double-sided polishing: Polish the obtained green body to 3mm on both sides to obtain lutetium aluminum garnet transparent ceramic with a high laser damage threshold.

[0042] The technical solutions described in the embodiments of this application above have at least the following technical effects or advantages:

[0043] See attached Figure 1 The linear transmittance of the laser-damage-resistant transparent ceramic prepared in this embodiment is compared with that of the transparent ceramic without phase reinforcement. The test results show almost no significant difference. This demonstrates that the transmittance was not significantly reduced.

[0044] See attached Figure 2 The laser-damage-resistant transparent ceramic prepared in this embodiment is compared with the laser damage threshold of ordinary transparent ceramics without phase reinforcement. The test results show that the transparent ceramic containing phase reinforcement has a laser damage threshold that is nearly doubled.

[0045] See attached Figure 3 The image shows a comparison of the grain morphology of the laser-damage-resistant transparent ceramic prepared in this embodiment with that of the transparent ceramic without phase reinforcement particles after damage, as captured by scanning electron microscopy. The test results show that the transparent ceramic without phase reinforcement particles exhibits obvious grain boundary cracks.

[0046] Example 2:

[0047] A method for preparing a laser-damage-resistant transparent ceramic, characterized by comprising the following steps:

[0048] Step 1, Powder Mixing: Lutetium aluminum garnet ceramic powder, strontium borate (SrB4O7) particles, anhydrous ethanol, and high-purity alumina balls are added to a nylon ball mill jar in a mass ratio of 1.0:0.12:2.5:5.0. The mixture is then ball-milled using a planetary ball mill at a speed of 200 r / min. -1 The ball milling time was 17 hours to obtain a slurry;

[0049] The second step is drying and sieving: After the powder is fully mixed, the ball-milled slurry is placed in an oven to dry at 70°C for 14 hours, and then passed through a 170-mesh nylon sieve to obtain uniform powder.

[0050] The third step is calcination: the powder is placed in a crucible and calcined at 780℃ for 8 hours. This removes organic impurities introduced during the ball milling process.

[0051] The fourth step is dry pressing: the calcined powder is dry pressed at a pressure of 120 MPa to obtain a green blank, and then cold isostatic pressing is used to further increase the density of the green blank. The cold isostatic pressing pressure is 280 MPa and the cold isostatic pressing time is 10 min.

[0052] Step 5, hot isostatic pressing: After the prepared green blank is pre-fired in an air atmosphere, it is then hot isostatically pressed in an argon atmosphere to eliminate residual porosity; the pre-fired temperature is 1450℃, the pre-fired time is 8h, the argon atmosphere is 1600℃ and 220MPa, and the hot isostatic pressing time is 4h.

[0053] Step 6, double-sided polishing: Polish the obtained green body to 3mm on both sides to obtain lutetium aluminum garnet transparent ceramic with a high laser damage threshold.

[0054] After observation, the main structural properties, transmittance, and damage threshold of the laser-damage-resistant transparent ceramic prepared in Example 2 are similar to those in Example 1.

[0055] Example 3:

[0056] A method for preparing a laser-damage-resistant transparent ceramic, characterized by comprising the following steps:

[0057] Step 1, Powder Mixing: Lutetium aluminum garnet ceramic powder, silicon carbide (SiC) particles, anhydrous ethanol, and high-purity alumina balls are added to a nylon ball mill jar in a mass ratio of 1.0:0.14:2.5:5.0. The mixture is then ball-milled using a planetary ball mill at a speed of 250 r / min. -1 The ball milling time was 16 hours to obtain a slurry;

[0058] The second step is drying and sieving: After the powder is fully mixed, the ball-milled slurry is placed in an oven to dry at 60°C for 13 hours, and then passed through a 180-mesh nylon sieve to obtain uniform powder.

[0059] The third step is calcination: the powder is placed in a crucible and calcined at 760℃ for 8 hours. This removes organic impurities introduced during the ball milling process.

[0060] The fourth step is dry pressing: the calcined powder is dry pressed at a pressure of 120 MPa to obtain a green blank, and then cold isostatic pressing is used to further increase the density of the green blank. The cold isostatic pressing pressure is 270 MPa and the cold isostatic pressing time is 9 min.

[0061] Step 5, hot isostatic pressing: After the prepared green blank is pre-fired in an air atmosphere, it is then hot isostatically pressed in an argon atmosphere to eliminate residual porosity; the pre-fired temperature is 1450℃, the pre-fired time is 8h, the argon atmosphere is 1700℃ and 210MPa, and the hot isostatic pressing time is 4h.

[0062] Step 6, double-sided polishing: Polish the obtained green body to 3mm on both sides to obtain lutetium aluminum garnet transparent ceramic with a high laser damage threshold.

[0063] After observation, the main structural properties, transmittance, and damage threshold of the laser-damage-resistant transparent ceramic prepared in Example 3 are similar to those in Example 1.

[0064] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0065] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the scope of the invention.

[0066] The spirit and scope of the invention are as follows: Thus, if these modifications and variations of the invention fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a laser-damage-resistant transparent ceramic, characterized in that, Specifically, the following steps are included: Step 1, Powder Mixing: Lutetium aluminum garnet ceramic powder, commercial phase-reinforcing particles, anhydrous ethanol, and high-purity alumina balls are added to a nylon ball mill jar and ball-milled using a planetary ball mill to obtain a slurry; the commercial phase-reinforcing particles in the first step are one or more of zirconium oxide (ZrO2) particles, strontium borate (SrB4O7) particles, boron nitride (BN) particles, and silicon carbide (SiC) particles; the mass ratio of lutetium aluminum garnet ceramic powder, commercial phase-reinforcing particles, anhydrous ethanol, and high-purity alumina balls in the first step is 1.0:0.05-0.15:2.5:5.0; the ball milling speed is 200-300 r·min. −1 The ball milling time is 10-18 hours; The second step is drying and sieving: After the powder is fully mixed, the slurry after ball milling is placed in an oven to dry, and then passed through a 100-200 mesh nylon sieve to obtain uniform powder. The third step is calcination: the powder is placed in a crucible and calcined to remove organic impurities introduced during the ball milling process; The fourth step is dry pressing: the calcined powder is dry pressed under pressure to obtain a green blank, and then cold isostatic pressing is used to further increase the density of the green blank. Step 5, hot isostatic pressing: After the prepared green blank is pre-fired in an air atmosphere, it is then hot isostatically pressed in an argon atmosphere to eliminate residual porosity; in the fifth step of hot isostatic pressing, the pre-fired temperature is 1400-1600℃, the pre-fired time is 6.5-10h, the argon atmosphere is 1500-1800℃, 180-220MPa, and the hot isostatic pressing time is 2-6h. Step 6, double-sided polishing: Polish the transparent ceramic obtained by hot isostatic pressing to 3-6mm on both sides to obtain lutetium aluminum garnet transparent ceramic with a high laser damage threshold.

2. The method for preparing laser-damage-resistant transparent ceramic according to claim 1, characterized in that: In the second step, the drying temperature is 60-75℃ and the drying time is 15-20 hours.

3. The method for preparing laser-damage-resistant transparent ceramics according to claim 1, characterized in that: The calcination temperature in the third step is 750-850℃, and the calcination time is 5-9 hours.

4. The method for preparing laser-damage-resistant transparent ceramic according to claim 1, characterized in that: In the fourth step, the dry pressing pressure is 15-25 MPa, the cold isostatic pressing pressure is 200-300 MPa, and the cold isostatic pressing time is 5-10 min.

5. The method for preparing laser-damage-resistant transparent ceramic according to claim 1, characterized in that: In the sixth step, the transparent ceramic is polished to 3mm on both sides.

6. A laser-damage-resistant transparent ceramic prepared by any one of the preparation methods described in claims 1-5.

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