A low expansion coefficient cordierite powder and its preparation method
By optimizing the raw material composition and preparation process of cordierite powder, the problems of large thermal expansion coefficient and narrow sintering range of commercial powders have been solved, realizing powder materials with low expansion coefficient and high density, which are suitable for high-precision semiconductor manufacturing equipment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NINGBO INST OF MATERIALS TECH & ENG CHINESE ACAD OF SCI
- Filing Date
- 2024-12-30
- Publication Date
- 2026-06-30
AI Technical Summary
In the existing technology, commercial cordierite powder contains impurities that result in a large coefficient of thermal expansion, making it difficult to achieve near-zero expansion at room temperature. It also has a narrow sintering range and is prone to residual porosity, which affects the processing of high-precision components and the accuracy of photolithography.
By optimizing the raw material composition and preparation process, using the ratio of MgO, Al2O3, SiO2, colorant and thermal expansion regulator, and combining ball milling, spray granulation and calcination processes, cordierite powder with a particle size of 0.6 to 3 μm with a low expansion coefficient was prepared, and the brightness and thermal expansion coefficient were controlled within a specific range.
It achieves a near-zero coefficient of thermal expansion at room temperature, broadens the sintering temperature range, reduces residual porosity, improves material density and photolithography accuracy, and reduces optical errors, making it suitable for applications in high-precision semiconductor manufacturing equipment.
Smart Images
Figure CN122301544A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of cordierite powder technology, specifically relating to a cordierite powder with a low expansion coefficient and its preparation method. Background Technology
[0002] Cordierite, as a unique ceramic material, plays an irreplaceable role in many high-tech fields due to its superior physical and chemical properties. It not only has a low coefficient of thermal expansion, enabling it to withstand drastic temperature changes without cracking or deformation, but also possesses a low dielectric constant and extremely low dielectric loss. These characteristics make it an ideal choice for applications such as high-temperature kiln furniture, honeycomb ceramic catalyst supports, and porous ceramic filter membranes.
[0003] With the advancement of materials science, the development of cordierite ceramic components with near-zero expansion characteristics at room temperature has become a new goal in the field in recent years. This will enable advanced semiconductor manufacturing equipment and play a crucial role in ensuring high precision.
[0004] However, the preparation of near-zero expansion cordierite ceramic materials at room temperature still faces challenges. A key factor is the lack of high-performance cordierite powder as a raw material. The main problems include: commercially available cordierite powder contains approximately 2 wt% impurities such as Na₂O, K₂O, CaO, and Fe₂O₃, resulting in a large coefficient of thermal expansion and making it difficult to achieve near-zero expansion at room temperature; commercially available cordierite powder has a narrow sintering range, easily retains residual pores, and is difficult to fully densify, thus hindering the processing into high-precision components; uneven light reflection and absorption lead to excessive reflection affecting photolithography accuracy, or excessive absorption causing thermal expansion due to component temperature changes, affecting accuracy. Therefore, the development of high-performance cordierite powder is of significant practical importance. Summary of the Invention
[0005] To address the aforementioned shortcomings in the prior art, this invention provides a cordierite powder with a low coefficient of expansion and a method for its preparation.
[0006] One objective of this invention is achieved through the following technical solution:
[0007] A cordierite powder with a low coefficient of thermal expansion, comprising the following raw materials in the indicated mass fractions: MgO 13.7–16.0 wt%, Al2O3 31.5–33.4 wt%, SiO2 50.0–50.9 wt%, colorant 0.5–2 wt%, and thermal expansion regulator 0.5–2 wt%.
[0008] Preferably, the low-expansion-coefficient cordierite powder has a particle size D50 of 0.6–3 μm, a cordierite phase content ≥95 wt%, and a thermal expansion coefficient α of 0 < α ≤ 2 × 10⁻⁶ at 22°C. -8 / K, with a luminance coefficient of 50-70.
[0009] Preferably, the colorant is a mixture of MnO2, NiO, and CoO, wherein the mass ratio of MnO2, NiO, and CoO is (1-5):(1-5):(1-3). More preferably, it is 2:2:1.
[0010] Preferably, the thermal expansion regulator is a rare earth oxide, including one or more of yttrium oxide, lanthanum oxide, cerium oxide, and ytterbium oxide.
[0011] The second objective of this invention is achieved through the following technical solution:
[0012] A method for preparing cordierite powder with a low coefficient of expansion, the method comprising the following steps:
[0013] (1) Slurry preparation: Weigh MgO, Al2O3, SiO2, colorant and thermal expansion regulator and put them into ball mill jar. Add slurry solvent and ball mill to mix to obtain slurry;
[0014] (2) Spray granulation: The slurry obtained in step (1) is spray dried to obtain spherical granulated powder;
[0015] (3) Calcination synthesis: The spherical granulated powder obtained in step (2) is placed in a crucible and calcined in a high-temperature furnace to synthesize spherical cordierite coarse powder;
[0016] (4) Grinding and refining: Grinding solvent is added to the spherical cordierite coarse powder obtained in step (3) for grinding and refining. After drying, cordierite powder with low expansion coefficient can be obtained.
[0017] Preferably, in step (1), the slurry solvent is one or more of ethanol, isopropanol, N-methylpyrrolidone, toluene, dimethyl sulfoxide, and n-hexane.
[0018] Preferably, in step (1), the amount of slurry solvent added is 100% to 150% of the raw material mass.
[0019] Preferably, in step (1), the ball milling time is 2 to 4 hours.
[0020] Preferably, in step (2), the inlet air temperature of the spray drying is 150-200°C and the outlet air temperature is 70-100°C.
[0021] Preferably, in step (2), the particle size of the spherical granulated powder is 50-200 μm.
[0022] Preferably, in step (3), the spherical granulated powder is placed into an alumina crucible.
[0023] Preferably, in step (3), the calcination temperature is 1300-1360℃ and the holding time is 3-6h.
[0024] Preferably, in step (4), the grinding solvent is water and / or ethanol.
[0025] Preferably, in step (4), the amount of grinding solvent added is 1.5 to 2 times the mass of the coarse cordierite powder.
[0026] Preferably, in step (4), the grinding speed is 800-1400 rpm and the time is 1-5 h.
[0027] Preferably, in step (4), the particle size D50 of the low expansion coefficient cordierite powder is 0.6 to 3 μm.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] 1. This invention provides a cordierite powder with a low coefficient of thermal expansion, designed to meet the increasing demands for material performance in high-precision applications. By optimizing the selection and proportioning of raw materials and combining them with the preparation process, this invention effectively reduces the impact of impurities in cordierite on the coefficient of thermal expansion, successfully achieving a high-performance cordierite powder with a coefficient of thermal expansion approaching zero at room temperature.
[0030] 2. This invention provides a low-expansion-coefficient cordierite powder, which utilizes optimized raw materials and a unique preparation method. This invention broadens the traditional sintering temperature range, effectively reduces residual porosity, increases finished product density, facilitates dense sintering, and ensures the production of cordierite ceramic materials with uniform structure and excellent performance, achieving a maximum density of 99.9%.
[0031] 3. This invention provides a cordierite powder with a low coefficient of thermal expansion and a brightness coefficient within a specific range of 50-70. This ensures that the material will not interfere with the photolithography process due to excessive reflectivity, nor will it cause localized temperature rises due to excessive absorption, thus preventing thermal expansion problems. This helps maintain the stability of the internal environment of the equipment and reduces errors caused by temperature changes. This invention achieves precise control over light reflection and absorption by adjusting the proportion of raw material components. It ensures that the material surface reflects and absorbs light uniformly and consistently, avoiding problems such as light spots and shadows common in traditional materials, thereby improving imaging quality and positioning accuracy. This is crucial for semiconductor manufacturing equipment that requires highly precise operation, significantly reducing various errors caused by optical factors and improving production efficiency and product quality.
[0032] 4. This invention provides a method for preparing cordierite powder with a low coefficient of expansion. The process route is novel, reasonable, and easy to control. Spray granulation ensures uniform composition and size of the granulated powder; optimal selection of calcination temperature and time ensures sufficient reaction to synthesize cordierite while preserving good sintering activity; grinding to a particle size below 3μm results in uniform particle size and high sintering activity, which is beneficial for sintering densification. Furthermore, this process route is reasonable, the equipment is mature and stable, the preparation efficiency is high, it is suitable for the stable batch preparation of cordierite powder, and the cost is low. Attached Figure Description
[0033] Figure 1 The image shows the SEM image of cordierite powder with low expansion coefficient prepared in Example 1 of this invention.
[0034] Figure 2 The XRD pattern of cordierite powder with low expansion coefficient prepared in Example 1 of this invention. Detailed Implementation
[0035] The technical solution of the present invention will be further described below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, the accompanying drawings used herein are merely for better illustrating the content disclosed in the present invention and do not limit the scope of protection. It should also be understood that after reading the teachings of this invention, those skilled in the art can make various modifications or alterations to the invention, and these equivalent forms also fall within the scope defined by the appended claims.
[0036] Example 1
[0037] The low expansion coefficient cordierite powder in this embodiment is prepared from the following raw materials by mass fraction: MgO 15.2wt%, Al2O3 32.3wt%, SiO2 50.0wt%, MnO 20.8wt%, NiO 0.8wt%, CoO 0.4wt%, CeO 20.5wt%.
[0038] The preparation method of low expansion coefficient cordierite powder in this embodiment includes the following steps:
[0039] (1) Slurry preparation: Weigh the above raw materials and put them into a ball mill jar. Add 100% ethanol by weight of the raw material powder as a solvent and ball mill and mix for 4 hours to obtain a uniform slurry with good flowability.
[0040] (2) Spray granulation: The uniformly mixed slurry is sprayed and granulated. The inlet temperature of the spray granulator is controlled at 150℃ and the outlet temperature is 70℃ to obtain spherical granulated powder.
[0041] (3) Calcination synthesis of cordierite: The spherical granulated powder is placed in an alumina crucible and then placed in a muffle furnace and heated to 1360°C for calcination. The components in the granulated powder react at high temperature to obtain spherical coarse cordierite powder.
[0042] (4) Grinding and refining: Add 2 times the mass of pure water as solvent to the obtained spherical cordierite coarse powder and grind it at 1400 rpm for 5 hours until the particle size is 0.6 μm. The slurry is then placed in an oven to dry.
[0043] The low-expansion-coefficient cordierite powder prepared in this embodiment has a cordierite phase content of 99 wt%, a brightness coefficient of 50 (measured according to JIS Z8722-2000 standard), and a thermal expansion coefficient of 1×10⁻⁶ at 22℃. -8 / K, with a density of 99% after sintering.
[0044] Figure 1 The image shows the SEM image of cordierite powder with low expansion coefficient prepared in Example 1 of this invention. Figure 2 The image shows the XRD pattern of cordierite powder with a low coefficient of thermal expansion prepared in Example 1 of this invention. Figures 1-2 As can be seen from the above, the low expansion coefficient cordierite powder prepared in Example 1 of the present invention has a uniform composition and size, high densification degree, and excellent stability.
[0045] Example 2
[0046] The low expansion coefficient cordierite powder in this embodiment is prepared from the following raw materials by mass fraction: MgO 16.0wt%, Al2O3 31.5wt%, SiO2 50.0wt%, MnO 20.72wt%, NiO 0.72wt%, CoO 0.36wt%, and La2O3 0.7wt%.
[0047] The preparation method of low expansion coefficient cordierite powder in this embodiment includes the following steps:
[0048] (1) Slurry preparation: Weigh the above raw materials and put them into a ball mill jar. Add 100% ethanol by weight of the raw material powder as a solvent and ball mill and mix for 4 hours to obtain a uniform slurry with good flowability.
[0049] (2) Spray granulation: The uniformly mixed slurry is sprayed and granulated. The inlet temperature of the spray granulator is controlled at 200℃ and the outlet temperature is 90℃ to obtain spherical granulated powder.
[0050] (3) Calcination synthesis of cordierite: The spherical granulated powder is placed in an alumina crucible and heated to 1350℃ in a muffle furnace for calcination. The components in the granulated powder react at high temperature to obtain spherical coarse cordierite powder.
[0051] (4) Grinding and refining: Add 1.5 times the mass of pure water as solvent to the obtained spherical cordierite coarse powder and grind it at 1200 rpm for 1 hour until the particle size is 2μm. The slurry is then placed in an oven to dry.
[0052] The low-expansion-coefficient cordierite powder prepared in this embodiment has a cordierite phase content of 98 wt%, a brightness coefficient of 58, and a thermal expansion coefficient of 1.2 × 10⁻⁶ at 22℃. -8 / K, with a density of 99% after sintering.
[0053] Example 3
[0054] The low expansion coefficient cordierite powder in this embodiment is prepared from the following raw materials by mass fraction: MgO 13.7wt%, Al2O3 33.4wt%, SiO2 50.5wt%, MnO 20.52wt%, NiO 0.52wt%, CoO 0.26wt%, and Y2O3 1.1wt%.
[0055] The preparation method of low expansion coefficient cordierite powder in this embodiment includes the following steps:
[0056] (1) Slurry preparation: Weigh the above raw materials and put them into a ball mill jar. Add 100% ethanol by weight of the raw material powder as a solvent and ball mill and mix for 3 hours to obtain a uniform slurry with good flowability.
[0057] (2) Spray granulation: The uniformly mixed slurry is sprayed and granulated. The inlet temperature of the spray granulator is controlled at 200℃ and the outlet temperature is 90℃ to obtain spherical granulated powder.
[0058] (3) Calcination synthesis of cordierite: The spherical granulated powder is placed in an alumina crucible and then placed in a muffle furnace and heated to 1330℃ for calcination. The components in the granulated powder react at high temperature to obtain spherical coarse cordierite powder.
[0059] (4) Grinding and refining: Add 1.5 times the mass of pure water as a solvent to the obtained spherical cordierite coarse powder and grind it at 800 rpm for 3 hours until the particle size is 3μm. The slurry is then placed in an oven to dry.
[0060] The low-expansion-coefficient cordierite powder prepared in this embodiment has a cordierite phase content of 96 wt%, a brightness coefficient of 62, and a thermal expansion coefficient of 1.5 × 10⁻⁶ at 22°C. -8 / K, with a density of 98% after sintering.
[0061] Example 4
[0062] The low expansion coefficient cordierite powder in this embodiment is prepared from the following raw materials by mass fraction: MgO 13.9wt%, Al2O3 32.8wt%, SiO2 50.9wt%, MnO 20.2wt%, NiO 0.2wt%, CoO 0.1wt%, and Yb2O3 1.9wt%.
[0063] The preparation method of low expansion coefficient cordierite powder in this embodiment includes the following steps:
[0064] (1) Slurry preparation: Weigh the above raw materials and put them into a ball mill jar. Add 100% ethanol by weight of the raw material powder as a solvent and ball mill and mix for 2 hours to obtain a uniform slurry with good flowability.
[0065] (2) Spray granulation: The uniformly mixed slurry is sprayed and granulated. The inlet temperature of the spray granulator is controlled at 180℃ and the outlet temperature is 80℃ to obtain spherical granulated powder.
[0066] (3) Calcination synthesis of cordierite: The spherical granulated powder is placed in an alumina crucible and heated to 1300℃ in a muffle furnace for calcination. The components in the granulated powder react at high temperature to obtain spherical coarse cordierite powder.
[0067] (4) Grinding and refining: Add 1.5 times the mass of pure water as solvent to the obtained spherical cordierite coarse powder and grind it at 1400 rpm for 4 hours until the particle size is 1μm. The slurry is then placed in an oven to dry.
[0068] The low-expansion-coefficient cordierite powder prepared in this embodiment has a cordierite phase content of 95 wt%, a brightness coefficient of 70, and a thermal expansion coefficient of 1 × 10⁻⁶ at 22°C. -8 / K, with a density of 99.9% after sintering.
[0069] Comparative Example 1
[0070] The only difference between this comparative example and Example 1 is that the cordierite powder is prepared from the following raw materials in the following mass fractions: MgO 12.0wt%, Al2O3 34.5wt%, SiO2 51.0wt%, MnO2 0.8wt%, NiO 0.8wt%, CoO 0.4wt%, CeO2 0.5wt%, and the rest is the same as in Example 1.
[0071] The cordierite powder prepared in this comparative example has a cordierite phase content of 93 wt%, a brightness coefficient of 48, and a thermal expansion coefficient of 3 × 10⁻⁶ at 22℃. -8 / K, with a density of 96% after sintering.
[0072] Comparative Example 2
[0073] The only difference between this comparative example and Example 1 is that the cordierite powder is prepared from the following raw materials in the following mass fractions: MgO 15.4wt%, Al2O3 32.5wt%, SiO2 50.1wt%, MnO2 0.8wt%, NiO 0.8wt%, CoO 0.4wt%, and the rest is the same as in Example 1.
[0074] The cordierite powder prepared in this comparative example has a cordierite phase content of 92 wt%, a brightness coefficient of 45, and a thermal expansion coefficient of 3.2 × 10⁻⁶ at 22℃. -8 / K, with a density of 93% after sintering.
[0075] As can be seen from the above embodiments and comparative examples, the cordierite powder prepared using the preparation method and raw material ratio within the scope of the present invention has a larger sintering range compared to conventional cordierite powder, which is beneficial for sintering and densification, with a maximum density of up to 99.9%, and its coefficient of thermal expansion is close to zero at room temperature. Simultaneously, the cordierite powder in the embodiments has a brightness coefficient of 50-70, exhibiting balanced light reflection and absorption, which is beneficial for the precision of semiconductor equipment manufacturing. Furthermore, the preparation method of the present invention has a novel and reasonable process route, is easy to control, and ensures uniform composition and size of the granulated powder through spray granulation; the calcination temperature and time are optimized to fully react and synthesize cordierite while preserving good sintering activity; grinding to a particle size of less than 3μm results in uniform particle size and high sintering activity, which is beneficial for sintering and densification; the preparation method of the present invention has a reasonable process route, mature and stable equipment, high preparation efficiency, is suitable for stable batch preparation of cordierite powder, and has low cost.
[0076] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.
[0077] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.
[0078] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.
Claims
1. A cordierite powder with a low coefficient of expansion, characterized in that, The low expansion coefficient cordierite powder comprises the following raw materials in the following mass fractions: MgO 13.7-16.0 wt%, Al2O3 31.5-33.4 wt%, SiO2 50.0-50.9 wt%, colorant 0.5-2 wt%, and thermal expansion regulator 0.5-2 wt%.
2. The cordierite powder with a low coefficient of expansion according to claim 1, characterized in that, The low-expansion-coefficient cordierite powder has a particle size D50 of 0.6–3 μm, a cordierite phase content ≥95 wt%, and a thermal expansion coefficient α of 0 < α ≤ 2 × 10⁻⁶ at 22℃. -8 / K, with a luminance coefficient of 50-70.
3. The cordierite powder with a low coefficient of expansion according to claim 1, characterized in that, The colorant is a mixture of MnO2, NiO and CoO, and the mass ratio of MnO2, NiO and CoO is (1-5):(1-5):(1-3).
4. The cordierite powder with a low coefficient of expansion according to claim 1, characterized in that, The thermal expansion regulator is a rare earth oxide, including one or more of yttrium oxide, lanthanum oxide, cerium oxide, and ytterbium oxide.
5. A method for preparing cordierite powder with a low coefficient of expansion as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: (1) Slurry preparation: Weigh MgO, Al2O3, SiO2, colorant and thermal expansion regulator and put them into ball mill jar. Add slurry solvent and ball mill to mix to obtain slurry; (2) Spray granulation: The slurry obtained in step (1) is spray dried to obtain spherical granulated powder; (3) Calcination synthesis: The spherical granulated powder obtained in step (2) is placed in a crucible and calcined in a high-temperature furnace to synthesize spherical cordierite coarse powder; (4) Grinding and refining: Grinding solvent is added to the spherical cordierite coarse powder obtained in step (3) for grinding and refining. After drying, cordierite powder with low expansion coefficient can be obtained.
6. The preparation method according to claim 5, characterized in that, In step (1), the slurry solvent is one or more of ethanol, isopropanol, N-methylpyrrolidone, toluene, dimethyl sulfoxide, and n-hexane; And / or, in step (1), the amount of slurry solvent added is 100% to 150% of the raw material mass; And / or, in step (1), the ball milling time is 2 to 4 hours.
7. The preparation method according to claim 5, characterized in that, In step (2), the inlet air temperature of the spray dryer is 150-200℃ and the outlet air temperature is 70-100℃. And / or, in step (2), the particle size of the spherical granulated powder is 50 to 200 μm.
8. The preparation method according to claim 5, characterized in that, In step (3), the spherical granulated powder is placed into an alumina crucible; And / or, in step (3), the calcination temperature is 1300-1360℃ and the holding time is 3-6h.
9. The preparation method according to claim 5, characterized in that, In step (4), the grinding solvent is water and / or ethanol; And / or, in step (4), the amount of grinding solvent added is 1.5 to 2 times the mass of the coarse cordierite powder.
10. The preparation method according to claim 5, characterized in that, In step (4), the grinding speed is 800-1400 rpm and the time is 1-5 h.