Fused quartz ceramic and method for producing the same

Abstract

This invention belongs to the field of fused silica ceramics technology, specifically relating to a fused silica ceramic and its preparation method. The preparation method includes the following steps: adding fused silica powder and an organic plasticizer to a mixer, mixing them evenly, and then cooling to obtain a mixture; pelletizing the mixture; injecting the pelletized mixture into a molding die, removing the die after molding to obtain a ceramic green body; and sintering the ceramic green body to obtain the fused silica ceramic.

Description

Technical Field

[0001] This invention belongs to the field of fused silica ceramics technology, specifically relating to a fused silica ceramic and its preparation method. Background Technology

[0002] Fused silica ceramics possess excellent properties such as strong chemical corrosion resistance, good thermal shock resistance, low thermal conductivity, and low coefficient of thermal expansion, and are widely used in aerospace, chemical, and energy fields.

[0003] Existing fused silica ceramics are mainly produced by molding methods such as slip casting, dry pressing, and isostatic pressing. These methods have poor control over dimensional accuracy, especially for ceramic products with complex shapes, making mass production difficult. Dimensional accuracy can only be achieved through machining, resulting in high costs and severely limited production capacity, which is detrimental to the development of fused silica ceramics. Summary of the Invention

[0004] To address the above problems, this invention provides a method for preparing fused silica ceramics, comprising the following steps:

[0005] Molten quartz powder and organic plasticizer are added to a mixer, mixed evenly, and then cooled to obtain a mixture.

[0006] The mixture is then pelletized.

[0007] The granulated mixture is injected into a molding die, and after molding, the die is removed to obtain a ceramic blank.

[0008] The ceramic blank is sintered to obtain fused silica ceramic.

[0009] Preferably, the fused silica powder comprises 75-90 parts by weight, and the organic plasticizer comprises 10-20 parts by weight.

[0010] Preferably, the fused silica powder comprises powder particles of 100-300 mesh, 300-1000 mesh, and larger than 1000 mesh;

[0011] The organic plasticizer includes binders, plasticizers, and surfactants.

[0012] Preferably, the adhesive comprises paraffin wax and methyl silicone resin;

[0013] The plasticizer includes any one or more of dibutyl phthalate (DBP), dioctyl phthalate (DOP), glycerin, and polyethylene glycol 200.

[0014] The surfactant includes any one or more of oleic acid, stearic acid, vegetable oil, and Tween 80.

[0015] Preferably, the proportions of the 100-300 mesh, 300-1000 mesh, and larger than 1000 mesh powder particles in the fused silica powder are (10%-20%), (15%-25%), and (60%-70%), respectively.

[0016] The proportions of the binder, plasticizer, and surfactant in the organic plasticizer are (75%-85%), (5%-10%), and (2%-5%), respectively.

[0017] Preferably, the binder, plasticizer, and surfactant are first added to the mixer for melting;

[0018] After the organic plasticizer in the mixer has melted evenly, the molten quartz powder is added to the mixer, mixed evenly, and then cooled to obtain a mixture.

[0019] Preferably, the melting temperature is 150-230℃;

[0020] The fused silica powder is added to the mixer in at least two batches.

[0021] Preferably, the pelletized mixture is cylindrical, with a diameter of 3-5 mm and a length of 3-5 mm.

[0022] Preferably, the sintering temperature of the sintering treatment is 1150-1200℃, and the holding time is 120-240min.

[0023] The present invention also designs a fused silica ceramic, which is prepared by the above-described preparation method.

[0024] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention introduces methyl silicone resin as a binder. During sintering, the methyl silicone resin undergoes oxidation and degradation into silicon dioxide, thereby improving the density and strength of the fused silica ceramic. The bulk density of the fused silica ceramic prepared by this invention ranges from 1.4 to 1.55 g / cm³. 3 Increased to 1.55-1.70 g / cm³ 3 The bending strength was increased from 12-25 MPa to 15-35 MPa.

[0025] The preparation method of this invention enables near-net-shape forming of fused silica ceramics with complex shapes, which helps to reduce costs and promotes the development of fused silica ceramics. Attached Figure Description

[0026] Figure 1 This is a flowchart of the preparation method according to an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0028] Example 1

[0029] This embodiment provides a method for preparing fused silica ceramics, including the following steps:

[0030] Step 1: Add a total of 10 parts by weight of binder, plasticizer, and surfactant to a mixer for melting at a melting temperature of 230°C. The binder comprises paraffin wax and methyl silicone resin, accounting for 85%; the plasticizer comprises dibutyl phthalate (DBP), accounting for 10%; and the surfactant comprises oleic acid, accounting for 5%.

[0031] Step 2: After the organic plasticizer in the mixer has melted evenly, add the first batch of molten quartz powder to the mixer and mix evenly. Then add the second batch of molten quartz powder and mix evenly. After mixing evenly, cool the mixture with cooling water to obtain the final mixture.

[0032] The first and second batches of fused silica powder totaled 90 parts by weight, comprising 10% 100-300 mesh powder, 25% 300-1000 mesh powder, and 65% powder larger than 1000 mesh.

[0033] Step 3: The mixture is pelletized to obtain cylindrical particles with a diameter of 3 mm and a length of 3 mm.

[0034] Step 4: Inject the granulated mixture into a molding die, and remove the die after molding to obtain the ceramic blank.

[0035] Step 5: Sinter the ceramic blank at 1150℃ and hold for 120 minutes to obtain fused silica ceramic.

[0036] Example 2

[0037] This embodiment provides a method for preparing fused silica ceramics, including the following steps:

[0038] Step 1: Add a total of 15 parts by weight of binder, plasticizer, and surfactant to a mixing mill for melting at a melting temperature of 200°C. The binder comprises paraffin wax and methyl silicone resin, accounting for 85%; the plasticizer comprises dioctyl phthalate (DOP) and glycerin, accounting for 10%; and the surfactant comprises stearic acid and vegetable oil, accounting for 5%.

[0039] Step 2: After the organic plasticizer in the mixer has melted evenly, add the molten quartz powder into the mixer in three batches. After mixing evenly, cool it with cooling water to obtain a mixture.

[0040] The three batches of fused silica powder totaled 85 parts by weight, comprising 20% ​​100-300 mesh powder, 20% 300-1000 mesh powder, and 60% powder larger than 1000 mesh.

[0041] Step 3: The mixture is pelletized to obtain cylindrical particles with a diameter of 4 mm and a length of 4 mm.

[0042] Step 4: Inject the granulated mixture into a molding die, and remove the die after molding to obtain the ceramic blank.

[0043] Step 5: Sinter the ceramic blank at 1175℃ and hold for 180 min to obtain fused silica ceramic.

[0044] Example 3

[0045] This embodiment provides a method for preparing fused silica ceramics, including the following steps:

[0046] Step 1: Add a total of 20 parts by weight of binder, plasticizer, and surfactant to a mixer for melting at a melting temperature of 150°C. The binder comprises paraffin wax and methyl silicone resin, accounting for 85%; the plasticizer comprises polyethylene glycol 200, accounting for 10%; and the surfactant comprises Tween 80, accounting for 5%.

[0047] Step 2: After the organic plasticizer in the mixer has melted evenly, add the first batch of molten quartz powder to the mixer and mix evenly. Then add the second batch of molten quartz powder and mix evenly. After mixing evenly, cool the mixture with cooling water to obtain the final mixture.

[0048] The first and second batches of fused silica powder totaled 80 parts by weight, comprising 15% 100-300 mesh powder, 15% 300-1000 mesh powder, and 70% powder larger than 1000 mesh.

[0049] Step 3: The mixture is pelletized to obtain cylindrical particles with a diameter of 5 mm and a length of 5 mm.

[0050] Step 4: Inject the granulated mixture into a molding die, and remove the die after molding to obtain the ceramic blank.

[0051] Step 5: Sinter the ceramic blank at 1200℃ and hold for 240 minutes to obtain fused silica ceramic.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. 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 of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing fused silica ceramic, characterized in that, Includes the following steps: Fused silica powder and organic plasticizer are added to a mixer, mixed evenly, and then cooled to obtain a mixture. The fused silica powder includes powder particles of 100-300 mesh, 300-1000 mesh, and larger than 1000 mesh. The mixture is then pelletized. The granulated mixture is injected into a molding die, and after molding, the die is removed to obtain a ceramic blank. The ceramic blank is sintered to obtain fused silica ceramic; The bulk density of the fused silica ceramic is 1.55-1.70 g / cm³. 3 The bending strength is 15-35 MPa; The organic plasticizer includes binders, plasticizers, and surfactants; The adhesive includes paraffin wax and methyl silicone resin; The plasticizer includes any one or more of dibutyl phthalate (DBP), dioctyl phthalate (DOP), glycerin, and polyethylene glycol 200. The surfactant includes any one or more of oleic acid, stearic acid, vegetable oil, and Tween 80; By weight, the fused silica powder is 75-90 parts and the organic plasticizer is 10-20 parts; The proportions of 100-300 mesh, 300-1000 mesh, and larger than 1000 mesh powder particles in the fused silica powder are 10%-20%, 15%-25%, and 60%-70%, respectively. The proportions of the binder, plasticizer, and surfactant in the organic plasticizer are 75%-85%, 5%-10%, and 2%-5%, respectively.

2. The preparation method according to claim 1, characterized in that, First, the binder, plasticizer, and surfactant are added to the mixer and melted. After the organic plasticizer in the mixer has melted evenly, the molten quartz powder is added to the mixer, mixed evenly, and then cooled to obtain a mixture.

3. The preparation method according to claim 2, characterized in that, The melting temperature is 150-230℃; The fused silica powder is added to the mixer in at least two batches.

4. The preparation method according to claim 1, characterized in that, The pelletized mixture is cylindrical, with a diameter of 3-5 mm and a length of 3-5 mm.

5. The preparation method according to claim 1, characterized in that, The sintering temperature of the sintering treatment is 1150-1200℃, and the holding time is 120-240min.

6. A fused silica ceramic, characterized in that, The fused silica ceramic is prepared by any one of the preparation methods described in claims 1-5.

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