Y2O3 transparent ceramic with low infrared absorption coefficient and preparation method thereof
Through the combination of vacuum heat treatment and pre-sintering, the problem of high vacuum high temperature sintering cost is solved, and a low infrared absorption Y2O3 transparent ceramic is prepared, which improves optical performance and laser output efficiency.
Patent Information
- Application Number
- CN202510526556.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-25
- Publication Date
- 2025-07-18
AI Technical Summary
In the prior art, when preparing Y2O3 transparent ceramics, the high vacuum and high temperature sintering steps are expensive, and the residual hydroxyl groups lead to broadband absorption in the 2.8-4 micron band affecting transmittance and absorption losses.
Vacuum heat treatment is used to eliminate residual hydroxyl groups at lower temperatures, combine air or oxygen pre-sintering and hot isostatic sintering to avoid high vacuum and high temperature steps, and high-quality transparent ceramics can be prepared using an ordinary sintering furnace.
It effectively eliminates the hydroxyl absorption band, improves the optical transparency of the ceramic, reduces the sintering cost, and improves the laser output efficiency.
Smart Images
Figure CN120329039A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of ceramic sintering, and particularly relates to a Y2O3 transparent ceramic with a low infrared absorption coefficient and a preparation method thereof. Background Art
[0002] Due to its excellent physical and chemical properties, yttrium oxide has a high melting point, resulting in high costs and difficulties in preparing single crystals. Therefore, Y2O3-based transparent ceramics have been widely studied and applied. Y2O3 transparent ceramics have a very low infrared emissivity and are ideal materials for infrared fairings and infrared windows. However, in yttrium oxide ceramics, if residual hydroxyl groups remain, strong broadband absorption will occur in the 2.8 - 4 micron band, which will affect the reduction of the material's transmittance and the increase of absorption loss, deteriorate the infrared emission coefficient, and affect the application of the ceramic in this band.
[0003] Traditional sintering of Y2O3 ceramics generally uses vacuum sintering combined with hot isostatic pressing. However, traditional vacuum sintering requires both high vacuum and high temperature. Especially for large sizes, high requirements are imposed on the vacuum sintering furnace, and high-vacuum sintering furnaces are expensive. If the high-vacuum sintering step at high temperature can be eliminated, the sintering cost will be greatly reduced. Summary of the Invention
[0004] Aiming at the deficiencies of the prior art, the present invention provides a Y2O3 transparent ceramic with a low infrared absorption coefficient and a preparation method thereof. The present invention uses a vacuum heat treatment method to first eliminate the residual hydroxyl groups in the sample at a relatively low temperature and a certain vacuum degree for yttrium oxide ceramics, and then high-quality transparent yttrium oxide ceramics can be prepared through air pre-sintering or oxygen pre-sintering combined with hot isostatic pressing sintering process.
[0005] The technical solution provided by the present invention is as follows:
[0006] The present invention provides a preparation method of a Y2O3 transparent ceramic with a low infrared absorption coefficient, comprising the following steps: Dry-press the Y2O3 powder into a shape, and obtain a ceramic green body through cold isostatic pressing treatment; Debind the ceramic green body at 600 - 1250 °C; Perform vacuum heat treatment on the debound green body at a vacuum degree ≤ 10 Pa and a temperature of 400 - 1550 °C to remove residual hydroxyl groups; Pre-sinter the sample after vacuum heat treatment in air or oxygen; Perform hot isostatic pressing sintering on the pre-sintered sample to achieve ceramic densification, and obtain Y2O3 transparent ceramics.
[0007] Further, the pressure for dry pressing is 5 - 10 MPa, and the pressure for cold isostatic pressing is 100 - 300 MPa.
[0008] Furthermore, the heating rate of debinding is 1-10 °C / min, and the heat preservation time is 2-10 h.
[0009] Furthermore, the temperature of the vacuum heat treatment is 600-1400 °C, and the heat preservation time is 2-10 h.
[0010] Furthermore, the temperature of pre-sintering is 1400-1700 °C, the heat preservation time is 1-15 h, and the heating rate is 1-10 °C / min.
[0011] Furthermore, the temperature of hot isostatic pressing sintering is 1350-1700 °C, the pressure is 100-250 MPa, and the heat preservation and pressure holding time is 1-5 h.
[0012] Furthermore, the protective gas for hot isostatic pressing sintering is argon or nitrogen.
[0013] The present invention also provides a Y2O3 transparent ceramic with a low infrared absorption coefficient, which is prepared according to the preparation method described above.
[0014] Beneficial effects
[0015] For the preparation method of a Y2O3 transparent ceramic with a low infrared absorption coefficient proposed by the present invention, the vacuum heat treatment method can eliminate the residual hydroxyl groups in the sample at a relatively low temperature and a certain vacuum degree. While traditional transparent ceramics usually adopt the method of vacuum pre-sintering combined with hot isostatic pressing sintering, the sintering temperature often needs to reach above 1450 °C, and the vacuum degree needs to reach below 5×10 -3 Pa. It requires both high vacuum and high temperature. The vacuum heat treatment method can effectively solve this problem. It can not only effectively eliminate the residual hydroxyl groups but also eliminate the high-vacuum sintering step at high temperature, greatly reducing the sintering cost. This method greatly eliminates the absorption band introduced by hydroxyl groups in yttrium oxide transparent ceramics, which can improve the optical transparency of the ceramics, thereby affecting the laser output efficiency. The prepared yttrium oxide ceramic has no broadband absorption in the 2.8-4 micron band and has excellent optical properties. Description of the drawings
[0016] Figure 1 It is the FTIR diagram of the samples of Y2O3 vacuum heat treatment followed by oxygen pre-sintering and hot isostatic pressing in Examples 1, 2, 3, 4, and 5 of the present invention;
[0017] Figure 2 It is the FTIR diagram of Y2O3 after oxygen pre-sintering and hot isostatic pressing in Comparative Example 1 of the present invention;
[0018] Figure 3 It is the FTIR diagram of Y2O3 after vacuum pre-sintering and hot isostatic pressing in Comparative Example 2 of the present invention;
[0019] Figure 4 These are the physical diagrams of the Y2O3 oxygen pre - sintering and vacuum pre - sintering for Comparative Example 1 and Comparative Example 2 of the present invention. Detailed implementation manners
[0020] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the following further elaborates on the present invention in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0021] Example 1
[0022] The embodiment of the present invention provides a preparation method of Y2O3 transparent ceramics with a low infrared absorption coefficient. The specific process is as follows:
[0023] Using the dry - pressing forming method, yttrium oxide powder is pressed into a green body with a certain shape in a stainless - steel mold at a pressure of 5 MPa. Then, the obtained green body is vacuum - sealed and cold isostatically formed at a pressure of 200 MPa. The yttrium oxide ceramic green body after cold isostatic pressing is degummed in a muffle furnace. The degumming system is as follows: heating at a rate of 5 °C / min to 1200 °C, holding for 5 h, and then cooling to room temperature at a rate of 5 °C / min.
[0024] Then, the degummed sample is subjected to vacuum heat treatment with a vacuum degree of 5 Pa. The heat treatment mechanism is as follows: heating at a rate of 5 °C / min to 600 °C, holding for 7 h, and then cooling to room temperature at a rate of 5 °C / min.
[0025] After that, the heat - treated sample is subjected to oxygen pre - sintering. The pre - sintering mechanism is as follows: heating at a rate of 5 °C / min to 1450 °C, holding for 7 h, and then cooling to room temperature at a rate of 5 °C / min.
[0026] After that, the pre - sintered ceramic is further subjected to hot isostatic pressing sintering. Heating at a rate of 10 °C / min to 1450 °C, and simultaneously filling high - pressure argon gas into the cavity. When the pressure reaches 200 MPa, hold the pressure for 2 h, and then cool to room temperature at a rate of 10 °C / min to obtain the Y2O3 yttrium transparent ceramic with a low infrared absorption coefficient.
[0027] Example 2
[0028] Change the vacuum heat - treatment temperature to 800 °C, and then use the process of Example 1 to prepare the Y2O3 yttrium transparent ceramic with a low infrared absorption coefficient.
[0029] Example 3
[0030] Change the vacuum heat - treatment temperature to 1000 °C, and use the process of Example 1 to prepare the Y2O3 yttrium transparent ceramic with a low infrared absorption coefficient.
[0031] Example 4
[0032] Change the vacuum heat treatment temperature to 1200 °C, and prepare the low infrared absorption coefficient Y2O3 yttrium oxide transparent ceramic by the process of Example 1.
[0033] Example 5
[0034] Change the vacuum heat treatment temperature to 1400 °C, and prepare the low infrared absorption coefficient Y2O3 yttrium oxide transparent ceramic by the process of Example 1.
[0035] Comparing Examples 1, 2, 3, 4, and 5, it can be found that when using vacuum heat treatment at 1200 °C, there is no obvious hydroxyl absorption peak at 2.8 - 4 microns compared with vacuum heat treatment at 600 °C, 800 °C, 1000 °C, and 1400 °C. The FTIR of the samples after vacuum heat treatment and the FTIR of the samples after hot isostatic pressing of samples sintered in oxygen at different vacuum heat treatment temperatures + 1450 °C are as Figure 1 shown.
[0036] Comparative Example 1
[0037] The embodiment of the present invention provides a preparation method of a low infrared absorption coefficient Y2O3 transparent ceramic, and the specific process is as follows:
[0038] Use the dry pressing method to press yttrium oxide powder into a green body with a certain shape in a stainless - steel mold at a pressure of 5 MPa, then vacuum - seal the obtained green body and perform cold isostatic pressing at a pressure of 200 MPa. Debind the yttrium oxide ceramic green body after cold isostatic pressing in a muffle furnace, and the debinding system is as follows: heat up to 1200 °C at a heating rate of 5 °C / min, hold for 5 h, and then cool down to room temperature at a rate of 5 °C / min.
[0039] Then pre - burn the debound sample in oxygen, and the pre - burning mechanism is as follows: heat up to 1460 °C at a heating rate of 5 °C / min, hold for 7 h, and then cool down to room temperature at a rate of 5 °C / min.
[0040] After that, further perform hot isostatic pressing sintering on the pre - burned ceramic. Heat up to 1450 °C at a heating rate of 10 °C / min, and at the same time fill high - pressure argon gas into the cavity. When the pressure reaches 200 MPa, hold the pressure for 2 h, and then cool down to room temperature at a rate of 10 °C / min.
[0041] For the Y2O3 transparent ceramic prepared by the above oxygen pre - burning method, an obvious hydroxyl absorption peak can be seen at 2.8 - 4 microns, and its FTIR is as Figure 2 shown, and the physical diagram of oxygen pre - burning is as Figure 4 shown.
[0042] Comparative Example 2
[0043] An embodiment of the present invention provides a method for preparing a Y2O3 transparent ceramic with a low infrared absorption coefficient. The specific process is as follows:
[0044] Use the dry pressing method to press yttrium oxide powder into a green body with a certain shape in a stainless steel mold at a pressure of 5 MPa. Then, vacuum-seal the obtained green body and perform cold isostatic pressing at a pressure of 200 MPa. Debind the yttrium oxide ceramic green body after cold isostatic pressing in a muffle furnace. The debinding system is as follows: heat up to 1200 °C at a heating rate of 5 °C / min, hold for 5 h, and then cool to room temperature at a rate of 5 °C / min.
[0045] Then, perform vacuum pre-sintering on the debound sample. The vacuum degree is 5×10 -3 Pa. The pre-sintering mechanism is as follows: heat up to 1460 °C at a heating rate of 5 °C / min, hold for 7 h, and then cool to room temperature at a rate of 5 °C / min.
[0046] After that, further perform hot isostatic pressing sintering on the pre-sintered ceramic. Heat up to 1450 °C at a heating rate of 10 °C / min, and at the same time, fill high-pressure argon gas into the cavity. When the pressure reaches 200 MPa, hold the pressure for 2 h, and then cool to room temperature at a rate of 10 °C / min.
[0047] For the Y2O3 transparent ceramic prepared by the above vacuum pre-sintering method, it can be found that there is no hydroxyl absorption peak at 2.8 - 4 μm, and its FTIR is as Figure 3 shown, and the physical picture of the vacuum pre-sintering is as Figure 4 shown.
[0048] The test data of the relevant parameters of the comparative examples and the examples are shown in Table 1:
[0049] Table 1
[0050]
[0051] Comparing the examples and the comparative examples, it can be seen that in Comparative Example 1, oxygen pre-sintering was used without vacuum heat treatment, and there was an obvious hydroxyl absorption peak in the 2.8 - 4 μm band, and the linear transmittance in the 3.4 μm band was only 80.6%; in Comparative Example 2, although the sample had excellent optical quality with vacuum pre-sintering, it had strict requirements for equipment. In addition to the sintering temperature needing to reach 1460 °C, the vacuum degree also needed to reach 5×10 -3Below Pa, this requires a high-temperature vacuum sintering furnace equipped with a tungsten heater, a tungsten-molybdenum thermal field, and circulating cooling water. In the embodiments of the present invention, under optimized processes, such as in Example 1, a significant increase in the linear transmittance of the sample (reaching 82.5%) can be achieved through low-temperature vacuum heat treatment at 600 °C. As the temperature of the vacuum heat treatment increases, such as in Examples 4 and 5, the linear transmittance in the 3.4-μm band reaches 85.3%, which is equivalent to the transmittance of the vacuum pre-sintered sample (Comparative Example 2), with excellent optical quality, which is beneficial to improving the laser output efficiency. The present invention adopts a process of vacuum heat treatment combined with air or oxygen pre-sintering and hot isostatic pressing sintering. At a relatively low vacuum heat treatment temperature (600-1400 °C) and a vacuum degree of 5 Pa, residual hydroxyl groups can be eliminated, eliminating the high-vacuum sintering step at high temperatures. The sintering process can be completed using an ordinary box furnace or tube furnace, reducing the requirements for equipment and greatly saving the sintering cost. Through reasonable setting of process parameters, the absorption band introduced by hydroxyl groups in yttrium oxide transparent ceramics is effectively eliminated, and the prepared yttrium oxide ceramics have no broadband absorption in the 2.8-4-μm band, with significantly improved optical transparency.
[0052] The test methods for the relevant parameters of this table are as follows:
[0053] Relative density measurement: The density of the sample is measured using the Archimedes drainage method, and the relative density of the ceramic is obtained by dividing the measured density by the theoretical density of Y2O3 ceramic.
[0054] Transmittance: The transmittance of Y2O3 ceramic in the 1250-9000 nm band is measured using an FTIR (Fourier transform infrared spectrometer) instrument.
[0055] The above are only the preferred embodiments of the present invention, and are not intended to limit the invention in other forms. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims
1. A preparation method of Y2O3 transparent ceramic with a low infrared absorption coefficient, characterized in that, It includes the following steps: Dry-press the Y2O3 powder into a green body, and obtain the ceramic green body through cold isostatic pressing; Debind the ceramic green body at 600~1250 °C; Perform vacuum heat treatment on the debound green body at a vacuum degree ≤10 Pa and a temperature of 400~1550 °C to remove residual hydroxyl groups; Pre-burn the sample after vacuum heat treatment in air or oxygen; Perform hot isostatic pressing sintering on the pre-burned sample to achieve ceramic densification and obtain Y2O3 transparent ceramic.
2. The preparation method according to claim 1, characterized in that, The pressure for the dry pressing is 5~10 MPa, and the pressure for the cold isostatic pressing is 100~300 MPa.
3. The preparation method according to claim 1, characterized in that, The heating rate for the debinding is 1~10 °C / min, and the heat preservation time is 2~10 h.
4. The preparation method according to claim 1, characterized in that, The temperature for the vacuum heat treatment is 600~1400 °C, and the heat preservation time is 2~10 h.
5. The preparation method according to claim 1, characterized in that, The temperature for the pre-burning is 1400~1700 °C, the heat preservation time is 1~15 h, and the heating rate is 1~10 °C / min.
6. The preparation method according to claim 1, characterized in that, The temperature for the hot isostatic pressing sintering is 1350~1700 °C, the pressure is 100~250 MPa, and the heat preservation and pressure holding time is 1~5 h.
7. The preparation method according to claim 1, characterized in that, The protective gas for the hot isostatic pressing sintering is argon or nitrogen.
8. A Y2O3 transparent ceramic with a low infrared absorption coefficient, characterized in that, Prepared by the preparation method according to any one of claims 1-7, the linear transmittance of the Y2O3 transparent ceramic at a wavelength of 500-6000 nm is not less than 80%.