Preparation method of calcium-yttrium-aluminum co-doped high-toughness zirconia ceramic
The preparation of calcium-yttrium-aluminum co-doped zirconia ceramics by reverse coprecipitation-hydrothermal method solves the problem of hardness and toughness imbalance in traditional zirconia ceramics in dental restoration, realizing a high-performance zirconia ceramic material suitable for the field of dental restoration.
Patent Information
- Application Number
- CN202511863366.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-11
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional zirconia ceramics cannot simultaneously meet the requirements of high hardness and high fracture toughness in dental restorations. Doping with a single element can lead to insufficient hardness or reduced toughness, affecting aesthetics and service life.
Calcium-yttrium-aluminum co-doped zirconia ceramics were prepared by reverse coprecipitation-hydrothermal method. By controlling the doping amount and hydrothermal treatment, fine nanoparticles were generated. Combined with dry pressing and low-temperature sintering, stable tetragonal phase nanoceramics were formed.
A zirconia ceramic with both high hardness and high fracture toughness was obtained. It has excellent material properties and can effectively replace 3Y-TZP in complex oral environments at a lower cost.
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Figure CN121573977A_ABST
Abstract
Description
Technical Field
[0001] This technology relates to the field of zirconia ceramic preparation technology, and more specifically, to a low-doped, high-toughness tetragonal zirconia nanoceramic powder and a method for preparing the ceramic. Background Technology
[0002] Zirconia ceramics, with their excellent biocompatibility, high mechanical strength, and outstanding aesthetic effects, have become an important material in the field of dental restoration. However, traditional zirconia ceramics (especially 3Y-TZP) face challenges of mechanical property imbalance in practical applications. This balance between hardness and toughness is particularly prominent in single-element doped systems. 1. Hardness defects under high toughness requirements: To maintain sufficient fracture toughness to resist chewing stress, the tetragonal phase transformation toughening ability must be retained, but this leads to insufficient material hardness, making the restoration surface prone to scratches and wear, affecting aesthetics and service life. 2. Toughness reduction under high hardness requirements: Through doping strengthening methods (such as introducing Al) 3+ Doping can increase hardness, but excessive doping can precipitate brittle phases, which may lead to a sharp drop in toughness and pose a risk of brittle fracture in the stress concentration area of the repair.
[0003] This makes it difficult for traditional materials to meet the dual requirements of high hardness and high fracture toughness in dental restorations within the complex oral environment. Multi-component doping promises to solve this balance problem. Simultaneously, using an anti-co-precipitation method, the mixture solution is slowly dripped into an excess of concentrated ammonia water. This method causes a rapid increase in the alkali content during the reaction, leading to high supersaturation. This high supersaturation ensures a higher nucleation rate for the zirconia precursor. Subsequent hydrothermal treatment directly generates fine-sized zirconia nanoparticles, avoiding the powder particle agglomeration and size increase caused by conventional calcination.
[0004] The calcium yttrium aluminum ceramic sample synthesized in this invention possesses both hardness and fracture toughness. Its excellent mechanical properties can well meet the application requirements of zirconia ceramics, providing a promising solution to address the insufficient toughness of existing zirconia ceramics in clinical applications. Summary of the Invention
[0005] The purpose of this invention is to prepare a ceramic material with low doping content, capable of stabilizing the tetragonal phase at room temperature, and possessing mechanical properties.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing calcium yttrium aluminum co-doped high-toughness zirconia ceramic includes the following steps: (1) A mixture of zirconium salt, calcium salt, yttrium salt and aluminum salt is added to an alkaline solution, and a zirconium oxide suspension is obtained by reverse coprecipitation-hydrothermal method; (2) The obtained zirconium oxide suspension was centrifuged, washed, dried and ground to obtain ultrafine pure tetragonal phase nano-zirconia powder; (3) The calcium yttrium aluminum co-doped high-toughness zirconia ceramic is obtained by dry pressing and sintering ultrafine pure tetragonal phase nano zirconia powder.
[0007] Furthermore, the particle size of the ultrafine pure tetragonal phase nano-zirconia powder is 9 nm, wherein the molar percentage doping amounts of CaO, Y2O3 and Al2O3 are 1%, 1% and 0.3%, respectively.
[0008] Furthermore, the zirconium salt used in step (1) is zirconium oxychloride; the calcium salt is calcium nitrate; the yttrium salt is yttrium nitrate; the aluminum salt is aluminum nitrate; and the alkaline solution is ammonia water with a concentration of 25 wt%.
[0009] Furthermore, in step (1), the hydrothermal temperature is 200 ℃ and the heat preservation time is 6 h.
[0010] Furthermore, the washing solution used in step (2) includes deionized water and anhydrous ethanol.
[0011] Furthermore, in step (3), the pressure used for dry pressing is 10 MPa and the holding time is 30 s.
[0012] Furthermore, in step (3), the sintering heating rate is 3 ℃ / min, the sintering temperature is 1200 ℃, the sintering time is 2 h, and the sintering cooling rate is 3 ℃ / min.
[0013] Furthermore, the fracture toughness of the prepared tetragonal zirconia nanoceramics is 14.2 MPa·m. 1 / 2 Its hardness is 11.8 GPa.
[0014] Furthermore, the prepared calcium yttrium aluminum co-doped high-toughness zirconia ceramic has a grain size of 172 nm.
[0015] Furthermore, in the prepared calcium yttrium aluminum co-doped high-toughness zirconia ceramic, the molar ratio of CaO:Y2O3:Al2O3:ZrO2 is 1:1:0.3:97.7.
[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a reverse coprecipitation-hydrothermal method to prepare room-temperature stable ultrafine tetragonal zirconia nanoparticles with a particle size of 9 nm, which is among the lowest reported. Low-doped, high-performance calcium yttrium aluminum zirconia ceramics are obtained through dry pressing and sintering at a lower temperature. This invention leverages the phase transformation toughening and grain refinement properties of zirconia, refining the grain size while obtaining a large amount of metastable tetragonal phase under low-doping conditions, achieving excellent mechanical properties that well meet the application requirements of zirconia.
[0017] Compared to conventional commercial zirconia, this invention achieves high-toughness tetragonal yttrium aluminum zirconia nanoceramics with a grain size of 172 nm using a very low concentration of cost-effective dopant. In the field of dental restoration, it can effectively replace the commonly used 3Y-TZP, while being less expensive. Attached Figure Description
[0018] Figure 1 This is the XRD pattern of the calcium yttrium aluminum multi-doped nano-zirconia powder synthesized in Example 1 of this invention.
[0019] Figure 2 This is the XRD pattern of the calcium yttrium aluminum multi-doped nano-zirconia ceramic synthesized in Example 1 of this invention.
[0020] Figure 3 This is the SEM image of the calcium yttrium aluminum multi-doped nano-zirconia ceramic synthesized in Example 1 of this invention.
[0021] Figure 4 This is an indentation optical image of the calcium yttrium aluminum multi-doped nano-zirconia ceramic synthesized in Example 1 of this invention. Detailed Implementation
[0022] To make the above-mentioned features and advantages of the present invention more apparent and understandable, specific embodiments are provided below for detailed description. Unless otherwise specified, the methods of the present invention are conventional methods in the art.
[0023] Example 1 Calcium-yttrium-aluminum co-doped zirconium oxide powder was synthesized by a reverse coprecipitation-hydrothermal method, uniaxially pressed, and pressureless sintered to prepare 1Ca x Y0.3Al sample ( x=0.5, 1, 1.5). The operating procedure, taking 1Ca1Y0.3Al as an example, is as follows: 12.426 g of zirconium oxychloride octahydrate, 0.0945 g of calcium nitrate tetrahydrate, 0.3064 g of yttrium nitrate hexahydrate, and 0.09 g of aluminum nitrate nonahydrate are dissolved in 800 ml of deionized water, and then added dropwise to 32 ml of 25 wt% ammonia water. The mixture is stirred at 500 r / min to induce precipitation. The resulting suspension is washed with water until pH=10, and then hydrothermally heated at 200 ℃ for 6 h to obtain a zirconium oxide suspension. This suspension is then washed multiple times with ethanol, dried, and ground to obtain zirconium oxide nanoparticles.
[0024] The proportions and sample numbers of the hydrothermal raw materials are shown in Table 1. 0.3 g of powder was weighed and placed into a 10 mm diameter mold. The powder was pressed into shape by uniaxial pressing at a pressure of 10 MPa for 30 s. Pressureless sintering was then carried out at 1200 ℃ with a heating rate of 3 ℃ / min, a cooling rate of 3 ℃ / min, and a holding time of 2 h.
[0025] Table 1. Various metallic raw materials and their quantities Example 2 Characterization of ceramic microstructure: The prepared 1Ca1Y0.3Al ceramic sample was subjected to SEM testing, and its SEM image is shown below. Figure 3 As shown, the prepared 1Ca1Y0.3Al ceramic has a uniform grain size distribution and a small grain size.
[0026] Example 3 Phase characterization: XRD analysis was performed on the prepared 1Ca0.5Y0.3Al, 1Ca1Y0.3Al, and 1Ca1.5Y0.3Al powders and ceramic samples. The powder XRD patterns are shown below. Figure 1 As shown, all samples exhibited peak broadening, which may be related to the small powder size. The powder size of the 1Ca1Y0.3Al sample was calculated to be 9 nm according to the Scherrer equation. A powder dominated by the tetragonal phase was obtained via reverse coprecipitation-hydrothermal method, with only a small amount of monoclinic phase present in 1Ca0.5Y0.3Al. The ceramic XRD pattern is shown below. Figure 2 As shown, the results indicate that the 1Ca1Y0.3Al ceramic prepared in Example 1 is a pure tetragonal phase. The 1Ca1.5Y0.3Al sample can also be a stable tetragonal phase at room temperature, but the 1Ca0.5Y0.3Al sample contains a large amount of monoclinic phase.
[0027] Example 4 Ceramic bulk density characterization: The density of the prepared 1Ca0.5Y0.3Al, 1Ca1Y0.3Al, and 1Ca1.5Y0.3Al samples was tested using the Archimedes' buoyancy method. The test was repeated 5 times, and the average value was taken as the bulk density value. The bulk densities of the 1Ca0.5Y0.3Al, 1Ca1Y0.3Al, and 1Ca1.5Y0.3Al samples were 5.68 g / cm³. 3 6.04 g / cm 3 5.99 g / cm 3 .
[0028] Example 5 Indentation toughness and hardness characterization: The fracture toughness value was obtained by holding a 10 kg load for 15 s using a fracture toughness tester, repeating the measurement five times and averaging the results. The hardness value was obtained by holding a 1 kg load for 15 s using the same tester, repeating the measurement five times and averaging the results. The indentation toughness and hardness are shown in Table 2. Figure 4 This is an optical image of the indentation on the sample.
[0029] The indentation toughness of the 1Ca1Y0.3Al sample in Example 1 reached 14.2 MPa·m. 1 / 2 The hardness of the 1Ca1Y0.3Al sample is much higher than that of other samples in the series. The 1Ca0.5Y0.3Al sample has a large number of monoclinic phases, which affects the accuracy of the measurement. The hardness of the 1Ca1Y0.3Al sample in Example 1 reaches 11.8 GPa, which is comparable to that of the 1Ca1.5Y0.3Al sample.
[0030] Table 2. Specific mechanical property parameters of the Ca-Y-Al ceramic samples synthesized in Example 1 of this invention. The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0031] The above description is merely a few embodiments of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any modifications or alterations made by those skilled in the art without departing from the scope of the technical solution of the present invention using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing calcium yttrium aluminum co-doped high-toughness zirconia ceramic, characterized in that, Includes the following steps: (1) A mixture of zirconium salt, calcium salt, yttrium salt and aluminum salt is added to an alkaline solution, and a zirconium oxide suspension is obtained by reverse coprecipitation-hydrothermal method; (2) The obtained zirconium oxide suspension was centrifuged, washed, dried and ground to obtain ultrafine pure tetragonal phase nano-zirconia powder; (3) The calcium-yttrium-aluminum co-doped high-toughness zirconia ceramic is obtained by dry pressing and sintering ultrafine pure tetragonal phase nano-zirconia powder.
2. The method according to claim 1, characterized in that, The particle size of the ultrafine pure tetragonal phase nano-zirconia powder is 9 nm, in which the molar percentage doping amounts of CaO, Y2O3 and Al2O3 are 1%, 1% and 0.3%, respectively.
3. The method according to claim 1, characterized in that, In step (1), the zirconium salt is zirconium oxychloride; the calcium salt is calcium nitrate; the yttrium salt is yttrium nitrate; the aluminum salt is aluminum nitrate; and the alkaline solution is ammonia.
4. The method according to claim 1, characterized in that, In step (1), the hydrothermal temperature is 200 ℃ and the heat preservation time is 6 h.
5. The method according to claim 1, characterized in that, In step (2), the washing solution used includes deionized water and anhydrous ethanol.
6. The method according to claim 1, characterized in that, In step (3), the pressure used for dry pressing is 10 MPa and the holding time is 30 s.
7. The method according to claim 1, characterized in that, In step (3), the sintering heating rate is 3 ℃ / min; the sintering temperature is 1200 ℃; the sintering time is 2 h; and the sintering cooling rate is 3 ℃ / min.
8. A calcium yttrium aluminum co-doped high-toughness zirconia ceramic prepared by the preparation method according to any one of claims 1-7, characterized in that, The grain size of the calcium-yttrium-aluminum co-doped high-toughness zirconia ceramic is 172 nm.
9. The calcium-yttrium-aluminum co-doped high-toughness zirconia ceramic according to claim 8, characterized in that, The fracture toughness of calcium yttrium aluminum co-doped high-toughness zirconia ceramic is 14.2 MPa·m. 1 / 2 Its hardness is 11.8 GPa.
10. The calcium-yttrium-aluminum co-doped high-toughness zirconia ceramic according to claim 8, characterized in that, In calcium-yttrium-aluminum co-doped high-toughness zirconia ceramics, the molar ratio of CaO:Y2O3:Al2O3:ZrO2 is 1:1:0.3:97.7.