Aluminosilicate-MgO-YSZ quaternary composite ceramic material and preparation method thereof

Abstract

The invention discloses a preparation method of an aluminosilicate-MgO-YSZ quaternary composite ceramic material, and the preparation method comprises the following steps: 1) according to formula requirements, after Al2O3, SiO2, MgO and YSZ are preliminarily mixed, a wet ball milling process is adopted for ultrafine treatment, and mixed slurry is obtained; (2) carrying out spray granulation on the ball-milled mixed slurry, and preparing a corresponding molded blank by adopting an isostatic pressing molding process; 3) placing the molded blank in a vacuum sintering furnace, and sintering by step heating to obtain a sintered body; and 4) carrying out gradient cooling treatment on the sintered body to obtain the composite ceramic material. According to the preparation method provided by the invention, the aluminosilicate-MgO-YSZ quaternary composite ceramic material which is low in production cost and has intrinsic high whiteness and high strength characteristics is prepared by limiting the mass ratio of MgO / YSZ and limiting the molar ratio of Al / Si, combining a stepped sintering process in a sintering process and finally performing a gradient cooling process.

Description

Technical Field

[0001] This invention belongs to the field of ceramic materials technology, specifically relating to an aluminosilicate-MgO-YSZ quaternary composite ceramic material and its preparation method. Background Technology

[0002] The Al2O3-SiO2-MgO ternary ceramic system refers to ceramic materials mainly composed of alumina, silicon oxide, and magnesium oxide. Due to its excellent thermal stability, low coefficient of thermal expansion, and good chemical durability, it has become an important engineering and functional material. This system is widely used in electronic packaging substrates, high-temperature kiln furniture, heat exchangers, and high-end daily-use decorative ceramics.

[0003] However, the existing Al2O3-SiO2-MgO ternary ceramic system has insufficient mechanical properties, such as low bending strength. At the same time, its whiteness is low and its surface decoration is poor. It must rely on external glazing to obtain a smooth and beautiful appearance, which increases the complexity and cost of the process.

[0004] In existing technologies, to address the insufficient strength of current ternary ceramic systems, some scholars have proposed a technical solution to improve the flexural strength of materials by adding a high content (10-15 wt%) of yttrium-stabilized zirconia (YSZ). However, the high refractive index of the YSZ phase severely scatters light, leading to a significant decrease in the material's light transmittance and a significant increase in haze. Regarding improving the whiteness of ternary ceramic systems, some researchers have proposed reducing the iron oxide content to extremely low levels; however, this approach, on the one hand, leads to a sharp increase in raw material costs due to stringent requirements for raw material purity, thus increasing production costs; on the other hand, it requires higher sintering temperatures (≥ 1350℃) to achieve high whiteness and complete sintering, which not only increases energy consumption but also places higher demands on kiln equipment and process control. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the main objective of this invention is to provide an aluminosilicate-MgO-YSZ quaternary composite ceramic material and its preparation method.

[0006] The objective of this invention is achieved through the following technical solution: This invention provides a method for preparing an aluminosilicate-MgO-YSZ quaternary composite ceramic material, comprising the following steps: 1) According to the formula requirements, Al2O3, SiO2, MgO and YSZ are initially mixed and then subjected to ultrafine treatment by wet ball milling to obtain a mixed slurry; 2) After the ball-milled slurry is spray-granulated, it is then molded into the corresponding green body using an isostatic pressing process; 3) Place the formed blank in a vacuum sintering furnace and sinter it by stepwise heating to obtain the sintered body: 4) The sintered body is subjected to gradient cooling treatment to obtain composite ceramic material.

[0007] In some specific embodiments, the composite ceramic material comprises the following components by mass percentage: MgO: 3-6 wt%, YSZ: 5-10 wt%, wherein the mass ratio of MgO / YSZ is 0.6-1.0; the balance is a mixture of Al2O3 and SiO2, wherein the molar ratio of Al / Si is 1.8-2.2; wherein Fe2O3 ≤ 0.15%, and unavoidable impurities ≤ 0.2%.

[0008] In some specific embodiments, the wet ball milling in step 1) specifically involves using zirconia grinding balls with a Φ3mm, 5mm, and 10mm gradation as the grinding medium, with a ball-to-material ratio of (2-6):1, and using ethanol as the dispersion medium for continuous ball milling for 12 to 16 hours.

[0009] In some specific embodiments, the spray granulation process parameters in step 2) are: inlet temperature of 150-250℃ and granulation particle size D50 = 60-100μm.

[0010] In some specific implementations, the parameters of the static pressure forming process in step 2) are: holding pressure at 180-220MPa for 5-10 minutes.

[0011] In some specific embodiments, the sintering described in step 3) specifically refers to: First stage: Raise the temperature from room temperature to 800℃ at a uniform rate of 4-6℃ / minute; Second stage: Increase the temperature from 800℃ to 1250℃ at a rate of 6-10℃ / minute, and maintain this temperature at 1250℃ for 2 hours, keeping the oxygen partial pressure ≤5×10⁻⁶ throughout the process. -3 Pa.

[0012] In some specific embodiments, the cooling process in step 4) specifically refers to: Rapid cooling phase: Rapid cooling at 50-80℃ / minute within the 1250-800℃ range; Slow cooling stage: For temperatures below 800℃, use a cooling rate of 3-10℃ / min to allow natural cooling to reach room temperature.

[0013] As part of the same inventive concept, the present invention also provides an aluminosilicate-MgO-YSZ quaternary composite ceramic material, wherein the cross-section of the aluminosilicate-MgO-YSZ quaternary composite ceramic material includes, from the inside out, a core matrix layer, a transition layer and a surface glaze layer.

[0014] In some specific embodiments, the core substrate layer has a crystal content of ≥80% and a thickness of ≥500μm; the transition layer has a glass crystal content of ≥80% and a thickness of 100-150μm; and the surface glaze layer has a glass crystal content of ≥80% and a thickness of 50-80μm.

[0015] Compared with the prior art, the present invention has at least the following advantages: The preparation method provided by this invention achieves a synergistic improvement in flexural strength and whiteness by limiting the MgO / YSZ mass ratio to 0.6-1.0; while limiting the Al / Si molar ratio to 1.8-2.2 ensures the formation of an appropriate amount of mullite phase during sintering, while retaining sufficient SiO2 to form a grain boundary glass phase that promotes densification and self-glazing. This achieves optimized coexistence of the mullite and glass phases, providing a technical basis for phase separation and mass migration during sintering. Furthermore, combined with the stepped sintering process, it promotes the growth of Mg... 2+ The glass phase migrates and accumulates in the surface region, eventually forming a 50-80 μm thick surface glaze layer rich in glass phase. At the same time, during the sintering process, an interlocking network of mullite phase and YSZ whiskers is generated in situ. Combined with the continuous gradient distribution of glass phase content from the core to the surface, a 100-150 μm thick high-toughness transition layer is constructed. The core, due to the migration of glass phase and the full densification of equiaxed α-Al2O3 fine grains (crystal phase), forms a high-strength matrix of ≥500 μm. Finally, the gradient cooling process not only locks the glassy smooth structure of the surface glaze layer, but also effectively absorbs and redistributes the thermal stress generated by cooling in the gradient layer, avoiding stress concentration. The final product is an aluminosilicate-MgO-YSZ quaternary composite ceramic material with low production cost and intrinsic high whiteness and high strength. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0017] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values ​​with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values ​​listed herein include the endpoints of the range and all integers and fractions within that range.

[0018] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.

[0019] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.

[0020] Example 1 This embodiment provides a method for preparing an aluminosilicate-MgO-YSZ quaternary composite ceramic material, including the following steps: 1) According to the formula requirements, Al2O3, SiO2, MgO and YSZ are initially mixed and then transferred to a ball mill. At the same time, zirconia grinding balls with a Φ3mm, 5mm and 10mm gradation are used as grinding media, the ball-to-material ratio is 3:1, and ethanol is used as the dispersion medium. The mixture is continuously ball-milled for 12-16 hours to obtain a mixed slurry. 2) After the ball-milled slurry is spray-granulated, the inlet temperature of the spray granulation process is 150℃ and the particle size D50 = 60μm; the isostatic pressing process is used to hold the pressure at 180MPa for 10min to produce the corresponding molded blank. 3) Place the formed green body in a vacuum sintering furnace and sinter it by stepwise heating. The first stage involves heating from room temperature to 800℃ at a uniform rate of 4℃ / min; the second stage involves heating from 800℃ to 1250℃ at a rate of 6℃ / min and holding it at 1250℃ for 2 hours, maintaining an oxygen partial pressure ≤5×10⁻⁶ throughout the process. -3 Pa, to obtain the sintered body: 4) The sintered body is subjected to gradient cooling treatment, in which the rapid cooling stage is: rapid cooling at 50℃ / min in the range of 1250-800℃; and the slow cooling stage is: natural cooling to room temperature at a cooling rate of 3℃ / min below 800℃ to obtain the composite ceramic material.

[0021] The composite ceramic material comprises the following components by mass percentage: MgO: 6wt%, YSZ: 10wt%; the balance is a mixture of Al2O3 and SiO2, wherein the molar ratio of Al / Si is 1.8; wherein Fe2O3 ≤ 0.15%, and unavoidable impurities ≤ 0.2%.

[0022] Example This embodiment provides a method for preparing an aluminosilicate-MgO-YSZ quaternary composite ceramic material, including the following steps: 1) According to the formula requirements, Al2O3, SiO2, MgO and YSZ are initially mixed and then transferred to a ball mill. Zirconia grinding balls with a Φ3mm, 5mm and 10mm gradation are used as grinding media, the ball-to-material ratio is 3:1, and ethanol is used as the dispersion medium. The mixture is continuously ball-milled for 16 hours to obtain a mixed slurry. 2) After the ball-milled slurry is spray-granulated, the inlet temperature of the spray granulation process is 200℃ and the particle size D50 = 80μm; the isostatic pressing process is used to hold the pressure at 200MPa for 8min to produce the corresponding molded blank. 3) Place the formed blank in a vacuum sintering furnace and sinter by stepwise heating. The first stage involves heating from room temperature to 800℃ at a uniform rate of 5℃ / min; the second stage involves heating from 800℃ to 1250℃ at a rate of 8℃ / min and holding at 1250℃ for 2 hours, maintaining an oxygen partial pressure ≤5×10⁻⁶ throughout the process. -3 Pa, to obtain the sintered body: 4) The sintered body is subjected to gradient cooling treatment, in which the rapid cooling stage is: rapid cooling at 60℃ / min in the range of 1250-800℃; and the slow cooling stage is: natural cooling to room temperature at a cooling rate of 5℃ / min below 800℃ to obtain the composite ceramic material.

[0023] The composite ceramic material comprises the following components by mass percentage: MgO: 5wt%, YSZ: 7wt%; the balance being a mixture of Al2O3 and SiO2, wherein the molar ratio of Al / Si is 2.0; wherein Fe2O3 ≤ 0.15%, and unavoidable impurities ≤ 0.2%.

[0024] Example 3 This embodiment provides a method for preparing an aluminosilicate-MgO-YSZ quaternary composite ceramic material, including the following steps: 1) According to the formula requirements, Al2O3, SiO2, MgO and YSZ are initially mixed and then transferred to a ball mill. Zirconia grinding balls with a Φ3mm, 5mm and 10mm gradation are used as grinding media, the ball-to-material ratio is 3:1, and ethanol is used as the dispersion medium. The mixture is continuously ball-milled for 12 hours to obtain a mixed slurry. 2) After the ball-milled slurry is spray-granulated, the inlet temperature of the spray granulation process is 250℃ and the particle size D50 = 100μm; the isostatic pressing process is used to hold the pressure at 220MPa for 5min to produce the corresponding molded blank. 3) Place the formed blank in a vacuum sintering furnace and sinter by stepwise heating. The first stage involves heating from room temperature to 800℃ at a uniform rate of 6℃ / min; the second stage involves heating from 800℃ to 1250℃ at a rate of 10℃ / min and holding at 1250℃ for 2 hours, maintaining an oxygen partial pressure ≤5×10⁻⁶ throughout the process. -3 Pa, to obtain the sintered body: 4) The sintered body is subjected to gradient cooling treatment, in which the rapid cooling stage is: rapid cooling at 80℃ / min in the range of 1250-800℃; and the slow cooling stage is: natural cooling to room temperature at a cooling rate of 10℃ / min below 800℃ to obtain the composite ceramic material.

[0025] The composite ceramic material comprises the following components by mass percentage: MgO: 6wt%, YSZ: 8wt%, with the balance being a mixture of Al2O3 and SiO2, wherein the molar ratio of Al / Si is 2.2; wherein Fe2O3 ≤ 0.15%, and unavoidable impurities ≤ 0.2%.

[0026] This application takes Example 2 as an example to test the performance of the prepared aluminosilicate-MgO-YSZ quaternary composite ceramic material. The whiteness test was conducted using a D65 light source; the mechanical properties were tested according to T / CIET952-2024 "Specification for Performance Testing of Ceramic Matrix Composites"; and the surface roughness of the composite ceramic material was measured using a white light interferometer, and its roughness Ra=0.04μm was obtained.

[0027] The results are shown in Table 1: Table 1. Whiteness and mechanical properties of the composite ceramic material in Example 2 As can be seen from the data in the table, the aluminosilicate-MgO-YSZ quaternary composite ceramic material provided by this invention has excellent whiteness and mechanical properties, and also has a great cost advantage.

[0028] This application also conducted aging resistance tests on the prepared aluminosilicate-MgO-YSZ quaternary composite ceramic material. The specific test conditions were a 1000-hour aging resistance test in an aging chamber at 85℃ / 85%RH. The results are shown in Table 2. Table 2. Aging resistance test results of composite ceramic materials in Example 2 As can be seen from the data in the table, the aluminosilicate-MgO-YSZ quaternary composite ceramic material provided by this invention has excellent aging resistance.

[0029] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method of producing an aluminosilicate-MgO-YSZ quaternary composite ceramic material, characterized by, The method comprises the following steps: 1) according to the formula requirements, Al2O3, SiO2, MgO and YSZ are preliminarily mixed, then ultra-fined by wet ball milling process, and mixed slurry is obtained; 2) the mixed slurry after ball milling is granulated by spray, and then formed into corresponding green body by isostatic pressing process; 3) the green body is placed in a vacuum sintering furnace, and sintered by stepwise heating, and a sintered body is obtained; 4) the sintered body is subjected to gradient cooling treatment, and a composite ceramic material is obtained.

2. The method of making an aluminosilicate-MgO-YSZ quaternary composite ceramic material according to claim 4, wherein, The composite ceramic material comprises the following components in mass percentage: MgO: 3-6wt%, YSZ: 5-10wt%, wherein the mass ratio of MgO / YSZ is 0.6-1.0; the balance is a mixture of Al2O3 and SiO2, and the molar ratio of Al / Si is 1.8-2.2; wherein Fe2O3≤0.15%, and unavoidable impurities≤0.2%.

3. The method of making an aluminosilicate-MgO-YSZ quaternary composite ceramic material according to claim 4, wherein, In step 1), the wet ball milling is specifically as follows: zirconia balls with Φ3mm, 5mm and 10mm gradation are used as grinding medium, the ball-to-material ratio is (2-6):1, ethanol is used as dispersion medium, and continuous ball milling is performed for 12 to 16 hours.

4. The method of making an alumino-silicate-MgO-YSZ quaternary composite ceramic material according to claim 4, characterized in that, In step 2), the spray granulation process parameters are as follows: the inlet temperature is 150-250℃, and the granulation particle size D50 = 60-100μm.

5. The method of making an aluminosilicate-MgO-YSZ quaternary composite ceramic material according to claim 4, wherein, In step 2), the parameters of the isostatic pressing forming process are as follows: the pressure is maintained at 180-220MPa for 5-10min.

6. The method of making an alumino-silicate-MgO-YSZ quaternary composite ceramic material according to claim 4, wherein, In step 3), the sintering is specifically as follows: First stage: uniformly heated at 4-6℃ / min from room temperature to 800℃; Second stage: from 800℃ to 1250℃ at a rate of 6-10℃ / min, keep the temperature at 1250℃ for 2 hours, keep the oxygen partial pressure ≤5×10 -3 Pa during the process.

7. The method of making an alumino-silicate-MgO-YSZ quaternary composite ceramic material according to claim 4, wherein, In step 4), the cooling treatment is specifically as follows: Fast cooling stage: rapidly cooled at 50-80℃ / min in the range of 1250-800℃; Slow cooling stage: naturally cooled to room temperature at a cooling rate of 3-10℃ / min below 800℃.

8. The aluminosilicate-MgO-YSZ quaternary composite ceramic material according to any one of claims 1 to 7, characterized in that, The cross section of the aluminosilicate-MgO-YSZ quaternary composite ceramic material comprises a core matrix layer, a transition layer and a surface glaze layer from inside to outside.

9. The aluminosilicate-MgO-YSZ quaternary composite ceramic material of claim 1, wherein, The crystal content in the core matrix layer is ≥80%, and the thickness is ≥500μm; the glass crystal content in the transition layer is ≥80%, and the thickness is 100-150μm; the glass crystal content in the surface glaze layer is ≥80%, and the thickness is 50-80μm.

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