A method for preparing silicon carbide ceramics by microdroplet jetting

Abstract

This invention discloses a method for preparing microdroplet-jet-molded silicon carbide ceramics, comprising: mixing an active diluent, oligomer, initiator, fluorescent agent, binder, and other additives, heating and stirring, and defoaming to obtain a resin premix; adding silicon carbide to the resin premix and mixing thoroughly to obtain a microdroplet-jet printing slurry; and printing the microdroplet-jet printing slurry using a microdroplet-jet printing process to obtain microdroplet-jet-molded silicon carbide ceramics. The preparation method of this invention is simple, requires no powder pretreatment, and saves time and costs. The combination of fluorescent agent and binder significantly improves the storage time and stability of the microdroplet-jet slurry, and is also more conducive to printing.

Description

Technical Field

[0001] This invention belongs to the field of silicon carbide ceramics, and relates to a microdroplet jet-formed silicon carbide ceramic and its preparation method. Background Technology

[0002] Silicon carbide ceramics possess excellent properties such as high strength, high hardness, high thermal conductivity, and high chemical stability, and are widely used in aerospace, microelectronics, automotive, and nuclear industries. However, in recent years, the automotive and aerospace industries have had a strong demand for large-size, complex-structured silicon carbide parts, and the high hardness of silicon carbide makes it difficult to process, thus limiting its application. 3D printing, also known as additive manufacturing, is a rapid prototyping technology with advantages such as high efficiency, high precision, and high design sophistication, which can solve the problem of limited applications for silicon carbide.

[0003] The main technologies for 3D printing silicon carbide include Selective Laser Sintering (SLS), Direct Ink Writing (DIW), Binder Jetting (BJ), Fused Deposition Modeling (FDM), Stereolithography (SLA), and microdroplet jetting. Unlike metal 3D printing, ceramic materials cannot be directly printed by heating ceramic powder with a laser. Direct SLS parts inevitably develop cracks due to thermal stress during sintering, resulting in poor mechanical properties of the final product. A challenge with DIW technology is the low solid content in the ink, leading to low density in the ceramic preform. However, due to the high melting point of silicon carbide ceramics, FDM technology requires extremely high-performance printheads for forming silicon carbide ceramics. BJ technology can quickly print complex shapes while maintaining printing accuracy, but it limits the powder filling density, thus restricting the volume fraction of silicon carbide. SLA is currently the mainstream ceramic 3D printing technology, but due to the high light absorption and high refractive index of silicon carbide, and the difficulty in forming nano-sized silicon carbide powder, parameters such as the solidification thickness and solid content of the slurry are limited. Microdroplet jetting, based on the "discrete-superposition" principle, generates uniform microdroplets through a droplet ejector while simultaneously controlling the movement of the three-dimensional substrate. This allows the microdroplets to be precisely deposited at specific locations, fused together, and solidified, "stacking" point by point and layer by layer, thus achieving rapid printing of complex three-dimensional structures. This method has the following advantages: droplet-by-drop forming eliminates internal stress, saves printing material and reduces costs, and has higher precision than DIW technology. However, at present, microdroplet jetting printing of silicon carbide requires a large amount of solvent, making it difficult to achieve a dense blank during subsequent sintering, which is not conducive to meeting application requirements. Furthermore, nozzle clogging is prone to occur during the jetting process, affecting the formability. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art and provide a microdroplet jet-formed silicon carbide ceramic and its preparation method, thereby solving the problems of difficult forming and densification of existing microdroplet jet-formed silicon carbide ceramics.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] A microdroplet jet-formed silicon carbide ceramic, comprising:

[0007] 70–80 wt.% silicon carbide, 10–26 wt.% reactive diluent, 0–8 wt.% oligomer, 1–5 wt.% initiator, 1–3 wt.% fluorescent agent, 1–5 wt.% binder and 1–10 wt.% other additives.

[0008] Furthermore, the reactive diluent is one or more of isoborneol acrylate, lauryl acrylate, trimethylolpropane triacrylate, and tripropylene glycol diacrylate; the oligomer is polyurethane acrylate resin, bisphenol A epoxy acrylate resin, or phenolic epoxy acrylate resin; the initiator is one or more of dodecyl peroxide and benzoyl peroxide; the fluorescent agent is OBplus; the binder is one or more of glycerol and paraffin wax; and the other additives are one or more of BYK-110, BYK2155, and sodium polyacrylate.

[0009] Furthermore, the bulk density of the microdroplet-jet-formed silicon carbide ceramic is 3–3.2 g / cm³. 3 .

[0010] A method for preparing silicon carbide ceramics by microdroplet jetting includes:

[0011] The reactive diluent, oligomer, initiator, fluorescent agent, binder and other additives are mixed, heated and stirred, and defoamed to obtain a resin premix.

[0012] Silicon carbide is added to the resin premix and mixed thoroughly to obtain the microdroplet jet printing slurry;

[0013] Microdroplet jet printing slurry is printed into shape using a microdroplet jet printing process to obtain microdroplet jet-molded silicon carbide ceramics.

[0014] Furthermore, in the resin premix, the reactive diluent is one or more of isoborneol acrylate, lauryl acrylate, trimethylolpropane triacrylate, and tripropylene glycol diacrylate; the oligomer is polyurethane acrylate resin, bisphenol A epoxy acrylate resin, or phenolic epoxy acrylate resin; the initiator is one or more of dodecyl peroxide and benzoyl peroxide; the fluorescent agent is OBplus; the binder is one or more of glycerol and paraffin wax; and the other additives are one or more of BYK-110, BYK2155, and sodium polyacrylate.

[0015] Furthermore, the amount of silicon carbide added is 70-80 wt.%, the amount of reactive diluent added is 10-26 wt.%, the amount of oligomer added is 0-8 wt.%, the amount of initiator added is 1-5 wt.%, the amount of fluorescent agent added is 1-3 wt.%, the amount of binder added is 1-5 wt.%, and the amount of other additives added is 1-10 wt.

[0016] Furthermore, the heating temperature is 50–70°C.

[0017] Furthermore, the silicon carbide and resin premix are fully mixed by ball milling, wherein the ball milling jar and grinding balls are made of agate or tungsten carbide.

[0018] Furthermore, the mixing time of the ball milling process is 0.5 to 1 hour, and the rotation speed is 250 to 350 r / min.

[0019] Furthermore, the nozzle diameter of the microdroplet jet printing process is 100-200 μm, the movement speed is 5-10 mm / s, and the jetting frequency is 1-1.5 Hz.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention provides a method for preparing silicon carbide ceramics by microdroplet jetting. The method involves mixing an active diluent, oligomer, initiator, fluorescent agent, binder, and other additives to prepare a resin premix. Silicon carbide is then added to the resin premix and thoroughly mixed to obtain a microdroplet jetting printing slurry. The slurry is then formed using microdroplet jetting printing technology to obtain microdroplet jetted silicon carbide ceramics. This method is simple, requiring no powder pretreatment, thus saving time and costs. The combination of fluorescent agent and binder allows the binder to electrostatically adhere to the surface of the silicon carbide powder during the microdroplet jetting process. This not only increases the wettability between the silicon carbide powder and the resin but also provides good lubrication, reducing the likelihood of nozzle clogging and facilitating smooth printing. The cross-linking properties of the binder improve the settling properties of the silicon carbide slurry, significantly extending its storage time and stability. This enhances the internal stability of the silicon carbide slurry, resulting in a more uniform particle distribution and preventing molding defects caused by uneven particle distribution during the jetting process. Meanwhile, by improving settling properties and increasing storage time, the service life of the slurry can be extended, thereby reducing production costs and improving production efficiency.

[0022] This invention enables the preparation of silicon carbide ceramics by microdroplet jet molding, and the resulting ceramic products have excellent bulk density, reaching 3–3.2 g / cm³. 3 The density of the ceramic green body has been significantly improved compared to traditional preparation methods, resulting in superior physical and mechanical properties. In practical applications, it can meet the requirements of various harsh environments, maintaining good stability and durability, and providing broader possibilities for the application of ceramic materials in various fields. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a physical image of the microdroplet-jet-molded silicon carbide ceramic prepared in Example 1 of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0027] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0028] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0029] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0030] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0031] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0032] The present invention will now be described in further detail:

[0033] This invention provides a method for preparing silicon carbide ceramics by microdroplet jetting, comprising the following steps:

[0034] The reactive diluent, oligomer, initiator, fluorescent agent, binder and other additives are mixed and stirred at 50-70°C, and defoamed to obtain a resin premix.

[0035] Add silicon carbide to the resin premix, transfer it to an agate or tungsten carbide ball milling jar, add an appropriate amount of agate or tungsten carbide grinding balls, and mix thoroughly through ball milling for 0.5 to 1 hour at a speed of 250 to 350 r / min to obtain microdroplet jet printing slurry;

[0036] Microdroplet-printed silicon carbide ceramics were produced by printing microdroplet printing slurry using a microdroplet printing process. The bulk density of the resulting microdroplet-printed silicon carbide ceramics was 3–3.2 g / cm³. 3 .

[0037] Furthermore, the reactive diluent is one or a mixture of isoborneol acrylate, lauryl acrylate, trimethylolpropane triacrylate and tripropylene glycol diacrylate;

[0038] The oligomers are polyurethane acrylic resin, bisphenol A epoxy acrylic resin, or phenolic epoxy acrylic resin;

[0039] The initiator is one or a mixture of two of dodecyl peroxide and benzoyl peroxide;

[0040] The fluorescent agent is OBplus;

[0041] The binder is one or a mixture of glycerin and paraffin;

[0042] Other additives are one or more of BYK-110, BYK2155 and sodium polyacrylate.

[0043] Furthermore, the amount of silicon carbide added is 70-80 wt.%, preferably 74 wt.%;

[0044] The amount of reactive diluent added is 10-26 wt.%, preferably 12 wt.%.

[0045] The amount of oligomer added is 0 to 8 wt.%, preferably 3 wt.%.

[0046] The amount of initiator added is 1 to 5 wt.%, preferably 2 wt.%.

[0047] The amount of fluorescent agent added is 1-3 wt.%, preferably 1.5 wt.%.

[0048] The amount of adhesive added is 1 to 5 wt.%, preferably 2.5 wt.%.

[0049] The amount of other additives added is 1 to 10 wt.%, preferably 5 wt.%.

[0050] Furthermore, the microdroplet jet printing process conditions are as follows: nozzle diameter is 100–200 μm, movement speed is 5–10 mm / s, and jetting frequency is 1–1.5 Hz.

[0051] The present invention will be further described in detail below with reference to specific embodiments:

[0052] Example 1:

[0053] Take 8g lauryl acrylate, 4g trimethylolpropane triacrylate, 3g bisphenol A epoxy acrylate resin, 2g dodecyl peroxide, 1.5g OBplus, 2.5g glycerol and 5g BYK-110 respectively, stir at 50℃, and defoam to obtain resin premix.

[0054] The prepared resin premix was transferred to an agate ball mill jar, an appropriate amount of agate grinding balls were added, and 74g of silicon carbide powder was added. The mixture was thoroughly mixed in a ball mill for 1 hour at a speed of 290r / min to obtain microdroplet jet printing slurry.

[0055] The microdroplet-printed slurry was printed using a microdroplet printer. The nozzle diameter was set to 100 μm, the speed to 5 mm / s, and the ejection frequency to 1 Hz. The resulting microdroplet-printed silicon carbide ceramic was as follows: Figure 1 As shown, its bulk density reaches 3 g / cm³. 3 .

[0056] Example 2:

[0057] Take 11g lauryl acrylate, 10g tripropylene glycol diacrylate, 3g polyurethane acrylate, 1g benzoyl peroxide, 1g OBplus, 1g glycerol and 3g BYK-110 respectively, stir at 50℃, and defoam to obtain resin premix.

[0058] The prepared resin premix was transferred to an agate ball mill jar, an appropriate amount of agate grinding balls were added, and 70g of silicon carbide powder was added. The mixture was thoroughly mixed in a ball mill for 0.5 hours at a speed of 350r / min to obtain microdroplet jet printing slurry.

[0059] The microdroplet-printed slurry was printed using a microdroplet printer. With a nozzle diameter of 200 μm, a speed of 10 mm / s, and a jetting frequency of 1.5 Hz, the resulting microdroplet-printed silicon carbide ceramic achieved a bulk density of 3.2 g / cm³. 3 .

[0060] Example 3:

[0061] Take 10g lauryl acrylate, 3g trimethylolpropane triacrylate, 2g dodecyl peroxide, 3g OBplus, 1g glycerol and 1g BYK-110 respectively, stir at 50℃, and defoam to obtain resin premix.

[0062] The prepared resin premix was transferred to an agate ball mill jar, an appropriate amount of agate grinding balls were added, and 80g of silicon carbide powder was added. The mixture was thoroughly mixed in a ball mill for 1 hour at a speed of 250r / min to obtain microdroplet jet printing slurry.

[0063] The microdroplet-printed slurry was printed using a microdroplet printer. With a nozzle diameter of 150 μm, a speed of 7 mm / s, and a printhead frequency of 1 Hz, the resulting microdroplet-printed silicon carbide ceramic achieved a bulk density of 3 g / cm³. 3 .

[0064] Example 4:

[0065] Take 5g lauryl acrylate, 4g isoborneol acrylate, 3g bisphenol A epoxy acrylate resin, 2g dodecyl peroxide, 1g OBplus, 2g glycerol and 5g BYK-110 respectively, stir at 50℃, and defoam to obtain resin premix.

[0066] The prepared resin premix was transferred to an agate ball mill jar, an appropriate amount of agate grinding balls were added, and 78g of silicon carbide powder was added. The mixture was thoroughly mixed in a ball mill for 1 hour at a speed of 280r / min to obtain microdroplet jet printing slurry.

[0067] The microdroplet-printed slurry was printed using a microdroplet printer. With a nozzle diameter of 160 μm, a speed of 6 mm / s, and a jetting frequency of 11.5 Hz, the resulting microdroplet-printed silicon carbide ceramic achieved a bulk density of 3.2 g / cm³. 3 .

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A type of silicon carbide ceramic formed by microdroplet jetting, characterized in that, include: 70-80 wt.% silicon carbide, 10-26 wt.% reactive diluent, 0-8 wt.% oligomer, 1-5 wt.% initiator, 1-3 wt.% fluorescent agent, 1-5 wt.% binder and 1-10 wt.% other additives; The fluorescent agent is OBplus, and the binder is one or a mixture of two of glycerin and paraffin. The binder is electrostatically adsorbed and coated on the surface of silicon carbide powder, which not only increases the wettability between silicon carbide powder and resin, but also acts as a lubricant.

2. The microdroplet jet-formed silicon carbide ceramic according to claim 1, characterized in that, The reactive diluent is one or a mixture of isoborneol acrylate, lauryl acrylate, trimethylolpropane triacrylate, and tripropylene glycol diacrylate; the oligomer is polyurethane acrylate resin, bisphenol A epoxy acrylate resin, or phenolic epoxy acrylate resin; the initiator is one or a mixture of dodecyl peroxide and benzoyl peroxide; and the other additives are one or a mixture of BYK-110, BYK2155, and sodium polyacrylate.

3. The microdroplet jet-formed silicon carbide ceramic according to claim 1, characterized in that, The bulk density of the microdroplet-jet-molded silicon carbide ceramic is 3~3.2 g / cm³. 3 .

4. A method for preparing silicon carbide ceramic by microdroplet jetting according to any one of claims 1 to 3, characterized in that, include: The reactive diluent, oligomer, initiator, fluorescent agent, binder and other additives are mixed, heated and stirred, and defoamed to obtain a resin premix. Silicon carbide is added to the resin premix and mixed thoroughly to obtain the microdroplet jet printing slurry; Microdroplet jet printing slurry is printed into shape using a microdroplet jet printing process to obtain microdroplet jet-molded silicon carbide ceramics.

5. The method for preparing silicon carbide ceramics by microdroplet jetting according to claim 4, characterized in that, In the resin premix, the reactive diluent is one or more of isoborneol acrylate, lauryl acrylate, trimethylolpropane triacrylate, and tripropylene glycol diacrylate; the oligomer is polyurethane acrylate resin, bisphenol A epoxy acrylate resin, or phenolic epoxy acrylate resin; the initiator is one or more of dodecyl peroxide and benzoyl peroxide; the fluorescent agent is OBplus; the binder is one or more of glycerol and paraffin wax; and the other additives are one or more of BYK-110, BYK2155, and sodium polyacrylate.

6. The method for preparing silicon carbide ceramics by microdroplet jetting according to claim 4, characterized in that, The amount of silicon carbide added is 70-80 wt.%, the amount of reactive diluent added is 10-26 wt.%, the amount of oligomer added is 0-8 wt.%, the amount of initiator added is 1-5 wt.%, the amount of fluorescent agent added is 1-3 wt.%, the amount of binder added is 1-5 wt.%, and the amount of other additives added is 1-10 wt.

7. The method for preparing silicon carbide ceramics by microdroplet jetting according to claim 4, characterized in that, The heating temperature is 50~70℃.

8. The method for preparing silicon carbide ceramics by microdroplet jetting according to claim 4, characterized in that, The silicon carbide and resin premix are fully mixed by ball milling, and the ball milling jar and grinding balls in the ball milling process are made of agate or tungsten carbide.

9. The method for preparing silicon carbide ceramics by microdroplet jetting according to claim 8, characterized in that, The mixing time for the ball milling process is 0.5~1h, and the rotation speed is 250~350r / min.

10. The method for preparing silicon carbide ceramics by microdroplet jetting according to claim 4, characterized in that, The microdroplet jet printing process has a nozzle diameter of 100~200μm, a movement speed of 5~10mm / s, and a jetting frequency of 1~1.5Hz.

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