Additive preparation method of silicon carbide optical reflector based on green recycled biomass waste

Abstract

The invention discloses an additive preparation method of a silicon carbide optical reflector based on green recycled biomass waste, and relates to the technical field of optical element manufacturing. The problems that in a common silicon carbide additive manufacturing process, due to the interface problem of carbon and silicon, the migration distance of diffusion elements and other reasons, a long reaction path needs to be crossed for the carbon-silicon reaction, the generated reaction layer further plays a blocking role, the carbon-silicon reaction is difficult, the number of residual materials is large, and multiple times of synthesis are needed are solved. The space and distance required by the carbon-silicon reaction are reasonably controlled by prefabricating micropores and designing a complex multi-channel printing structure, the problems of long diffusion distance and reaction limitation of the carbon-silicon reaction are solved, the reaction time for element migration is shortened, and one-time in-situ synthesis of a silicon carbide three-dimensional structure is implemented. The invention can obtain the additive preparation method of the silicon carbide optical reflector based on the green recycled biomass waste.

Description

Technical Field

[0001] The present invention relates to the technical field of optical element manufacturing, and in particular to an additive manufacturing method for a silicon carbide optical reflector based on green recycled biomass waste. Background Art

[0002] With the increasing demand for the development of satellite remote sensing technology, optical reflectors, as the most important core components in space optical systems, have put forward higher requirements for their rapid preparation and the caliber and weight of optical reflectors, which has brought high manufacturing costs and huge marginal benefits to the design of space rockets for launching remote sensing satellites. Therefore, the lightweight technology of optical reflectors is urgent. The mature lightweight methods in industry mainly focus on two aspects: materials and structures. Optical reflectors naturally also put forward two lightweight research goals: the selection of low-density silicon carbide materials and weight reduction of structural design. This naturally brings complex physical structures to the silicon carbide processing technology, and the silicon carbide material itself also has the problems of difficult molding and inconvenient processing. Faced with the problems that traditional processes are difficult to deal with, additive manufacturing technology provides the possibility for the realization of complex physical structure silicon carbide optical reflectors.

[0003] At present, the preparation of silicon carbide optical reflectors mainly uses selective laser sintering 3D printing technology (CN117534471A). The printing material is a uniform mixture of carbon black powder, silicon carbide powder and binder. Through silicon-infiltrated reaction sintering, the overall molding of large-scale, complex and lightweight silicon carbide reflectors and the rapid and non-destructive homogenization of the mirror surface can be achieved. However, the carbon black powder and silicon carbide powder required for the reaction sintering of the workpiece often come from secondary deep processing and synthesis, and the uniformity and integrity of the synthesis are difficult to guarantee [1]. In addition, the prepared workpiece will also form a complex phase relationship during the reaction sintering stage, which makes the workpiece performance have a great risk of uncontrollable. This will increase the production cost of optical reflectors, affect the performance of materials, and cause great waste of energy and raw materials.

[0004] [1] Reference Vat photopolymerization of large-aperture high performance SiC mirror through multiphase carbon infiltration modification ID: doi.org / 10.1016 / j.addma.2024.104160. Summary of the invention

[0005] The purpose of the present invention is to solve the above technical problems and to provide an additive manufacturing method for silicon carbide optical reflectors based on green recycled biomass waste.

[0006] An additive manufacturing method for a silicon carbide optical reflector based on green recycling of biomass waste is carried out in the following steps:

[0007] Step S1: preparing a biomass mixed product;

[0008] The biomass waste, resin and pore-forming agent are mixed, and stirred at 60 to 160° C. for 0.5 to 3 hours to obtain a biomass mixed product;

[0009] Step S2: preparing biomass composite powder;

[0010] The biomass mixed product obtained in step S1 is crushed and ball-milled at 40-60° C., and sieved after the crushing and ball-milling to obtain a biomass composite powder;

[0011] Step S3: printing the biomass embryo;

[0012] Printing the biomass composite powder obtained in step S2 using additive manufacturing equipment to obtain a biomass embryo;

[0013] Step S4: preparing a carbon embryo with an optical reflector structure;

[0014] The biomass embryo obtained in step S3 is placed in a tubular furnace and cured at 60-180° C. for 4-15 hours; then the pore-forming agent is removed by high-temperature decomposition reaction or chemical reaction to form micropores on the surface of the biomass embryo; then a protective atmosphere is introduced and heated to 400-500° C., and the temperature is kept at 400-500° C. for 1-2 hours; after the insulation is completed, it is heated to 800-1000° C., and the temperature is continued to be kept at 800-1000° C. for 1-2 hours; after the insulation is completed, it is cooled with the furnace to obtain a carbon embryo with an optical reflector structure;

[0015] Step S5: preparing a silicon carbide optical reflector;

[0016] The carbon embryo obtained in step S4 is buried in silicon powder, heated to 1400-1600° C. in a vacuum environment, and kept warm at 1400-1600° C. for 1-2 hours; after the insulation is completed, it is cooled with the furnace to obtain a silicon carbide embryo; the silicon carbide embryo is ground and polished in sequence to obtain a silicon carbide optical reflector based on green recycled biomass waste.

[0017] Beneficial effects of the present invention:

[0018] (1) The present invention prepares silicon carbide optical reflectors from green and recyclable biomass waste, which can greatly save production costs, reduce energy waste, and provide a new way for the recycling of biomass waste, meeting the concept of green environmental protection.

[0019] (2) The present invention breaks the problem that the carbon-silicon reaction needs to cross a long reaction path due to the interface problem between carbon and silicon and the migration distance of the diffusion elements in the general silicon carbide additive manufacturing process, and the generated reaction layer will further hinder the reaction, causing the problems of difficulty in carbon-silicon reaction, large amount of residual materials, and multiple synthesis. The present invention reasonably controls the space and distance required for the carbon-silicon reaction by prefabricating micropores and designing a complex multi-channel printing structure, solves the problem of long diffusion distance and reaction limitation of the carbon-silicon reaction, reduces the reaction time for element migration, and implements a one-time in-situ synthesis of silicon carbide three-dimensional structure.

[0020] (3) The experimental platform of the present invention can directly use a mature selective laser sintering printer, which has a simple process, is easy to operate, safe and reliable.

[0021] The present invention can obtain an additive preparation method for a silicon carbide optical reflector based on green recycled biomass waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A physical picture showing the wood-plastic composite powder prepared in Example 1;

[0023] Figure 2 A process flow chart showing the present invention;

[0024] Figure 3 A schematic diagram showing the micropore design and carbon-silicon reaction sintering of the present invention;

[0025] Figure 4 A physical picture showing the silicon carbide optical reflector with a complex structure prepared in Example 1. DETAILED DESCRIPTION

[0026] Specific implementation method 1: This implementation method is an additive preparation method of silicon carbide optical reflector based on green recycling of biomass waste, which is carried out according to the following steps:

[0027] Step S1: preparing a biomass mixed product;

[0028] The biomass waste, resin and pore-forming agent are mixed, and stirred at 60 to 160° C. for 0.5 to 3 hours to obtain a biomass mixed product;

[0029] Step S2: preparing biomass composite powder;

[0030] The biomass mixed product obtained in step S1 is crushed and ball-milled at 40-60° C., and sieved after the crushing and ball-milling to obtain a biomass composite powder;

[0031] Step S3: printing the biomass embryo;

[0032] Printing the biomass composite powder obtained in step S2 using additive manufacturing equipment to obtain a biomass embryo;

[0033] Step S4: preparing a carbon embryo with an optical reflector structure;

[0034] The biomass embryo obtained in step S3 is placed in a tubular furnace and cured at 60-180° C. for 4-15 hours; then the pore-forming agent is removed by high-temperature decomposition reaction or chemical reaction to form micropores on the surface of the biomass embryo; then a protective atmosphere is introduced and heated to 400-500° C., and the temperature is kept at 400-500° C. for 1-2 hours; after the insulation is completed, it is heated to 800-1000° C., and the temperature is continued to be kept at 800-1000° C. for 1-2 hours; after the insulation is completed, it is cooled with the furnace to obtain a carbon embryo with an optical reflector structure;

[0035] Step S5: preparing a silicon carbide optical reflector;

[0036] The carbon embryo obtained in step S4 is buried in silicon powder, heated to 1400-1600° C. in a vacuum environment, and kept warm at 1400-1600° C. for 1-2 hours; after the insulation is completed, it is cooled with the furnace to obtain a silicon carbide embryo; the silicon carbide embryo is ground and polished in sequence to obtain a silicon carbide optical reflector based on green recycled biomass waste.

[0037] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is that the biomass waste described in step S1 is corn straw, wheat straw, rice straw or sawdust waste, with a particle size of 50 to 100 μm; the resin is a thermosetting or thermoplastic resin, including but not limited to polyethersulfone resin or phenolic resin, with a particle size of 20 to 60 μm; the pore-forming agent is ammonium bicarbonate, urea, calcium sulfate or sodium chloride, with a particle size of 2 to 10 μm.

[0038] The other steps are the same as those in the first specific implementation.

[0039] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that the stirring rate in step S1 is 600-2800 r / min; the stirring rate of the crushing ball mill in step S2 is 70-670 r / min.

[0040] The other steps are the same as those in the first or second embodiment.

[0041] Specific embodiment 4: The difference between this embodiment and specific embodiments 1 to 3 is that a sieve with 80-150 mesh is used for screening in step S2.

[0042] The other steps are the same as those in Specific Embodiments 1 to 3.

[0043] Specific embodiment five: The difference between this embodiment and specific embodiments one to four is that the additive manufacturing equipment in step S3 is a selective laser sintering 3D printer, and the process parameters are: laser power is 10~50W, scanning speed is 1.5~3.5m / s, scanning spacing is 0.05~0.2mm, printing layer thickness is 0.1~0.3mm, and preheating temperature is 50~80℃.

[0044] The other steps are the same as those in Specific Embodiments 1 to 4.

[0045] Specific implementation method six: The difference between this implementation method and specific implementation methods one to five is that: in step S4, heating is performed to 400-500°C at a heating rate of 1-10°C / min; after the insulation is completed, heating is performed to 800-1000°C at a heating rate of 1-10°C / min.

[0046] The other steps are the same as those in Specific Embodiments 1 to 5.

[0047] Specific implementation method 7: The difference between this implementation method and specific implementation methods 1 to 6 is that the grinding in step S5 is performed in sequence of coarse grinding and fine grinding.

[0048] The other steps are the same as those in Specific Embodiments 1 to 6.

[0049] Specific implementation eight: This implementation differs from specific implementations one to seven in that the rough grinding is performed by sequentially selecting an angle grinder, W40 abrasives and W28 abrasives to grind until the surface roughness reaches less than 1.6 μm.

[0050] The other steps are the same as those in Specific Embodiments 1 to 7.

[0051] Specific implementation method 9: The difference between this implementation method and specific implementation methods 1 to 8 is that the fine grinding is performed by selecting W28 abrasive, W14 abrasive, W10 abrasive and W7 abrasive in sequence.

[0052] The other steps are the same as those in Specific Embodiments 1 to 8.

[0053] Specific embodiment ten: The present embodiment differs from specific embodiments one to nine in that the polishing in step S5 is performed on a polishing machine at a rotation speed of 1500 to 2500 r / min, and the polishing liquid used is diamond polishing liquid.

[0054] The other steps are the same as those in Specific Embodiments 1 to 9.

[0055] The following examples are used to verify the beneficial effects of the present invention:

[0056] Example 1: Figure 2As shown, an additive manufacturing method for silicon carbide optical reflectors based on green recycled biomass waste is carried out in the following steps:

[0057] Step S1: preparing a wood-plastic mixed product;

[0058] Pine wood chips with a particle size of 95 μm were recycled as biomass waste as the basic material of 3D printing powder, polyethersulfone resin with a particle size of 58 μm and ammonium bicarbonate with a particle size of 2 μm were added, placed in a blade sand mixer, and stirred at a stirring rate of 600 r / min at 90 °C for 0.5 h to obtain a wood-plastic mixed product.

[0059] Step S2: preparing wood-plastic composite powder;

[0060] The wood-plastic mixed product was poured into a ball mill and crushed and ball-milled at 50°C with a stirring rate of 300 r / min. After the crushing and ball-milling, it was passed through an 80-mesh sieve to obtain a wood-plastic composite powder (such as Figure 1 shown).

[0061] Step S3: printing the wood-plastic biomass embryo;

[0062] The wood-plastic composite powder is placed in the printing chamber of a selective laser sintering 3D printer, preheated at 80°C, and sintered according to the printer parameters selected according to the pre-designed structural model to obtain a wood-plastic biomass embryo with a complex solid structure;

[0063] Process parameters: laser power is 12W, scanning speed is 2m / s, scanning spacing is 0.2mm, and printing layer thickness is 0.15mm.

[0064] Step S4: preparing a carbon embryo with an optical reflector structure;

[0065] The wood-plastic biomass embryo was placed in a tubular furnace and cured at 80°C for 10 hours. A protective atmosphere was then introduced and the embryo was heated to 500°C at a heating rate of 2 / min. The embryo was kept at 500°C for 1 hour to decompose the ammonium bicarbonate and form micropores. After the insulation, the embryo was heated to 1000°C at a heating rate of 2 / min and kept at 1000°C for 2 hours. After the insulation, the embryo was cooled in the furnace to obtain a carbon embryo with an optical reflector structure.

[0066] Step S5: preparing a silicon carbide optical reflector;

[0067] The carbon embryo is buried in silicon powder and heated to 1600°C in a vacuum environment so that the liquid silicon is fully in contact with the porous carbon embryo; the temperature is kept at 1600°C for 2 hours to allow the silicon powder and carbon to fully react; the silicon carbide embryo is cooled with the furnace after completion to obtain the silicon carbide embryo; the silicon carbide embryo is subjected to coarse grinding, fine grinding and polishing in sequence to obtain a silicon carbide optical reflector with a complex structure; the density of the silicon carbide formed by reaction sintering under the process of this embodiment can be increased from 2.65g / cm 3 Increased to 3.10g / cm 3 On the basis of ensuring the optical use requirements and heat dissipation performance, the apparent density of the reflector print can be reduced by about 10%.

[0068] For rough grinding, an angle grinder, W40 abrasive and W28 abrasive are selected in sequence to grind until the surface roughness reaches below 1.6μm. For fine grinding, W28 abrasive, W14 abrasive, W10 abrasive and W7 abrasive are selected in sequence to grind to meet the basic requirements of polishing. Polishing is carried out on a polishing machine at a speed of 2500r / min, and the polishing fluid used is diamond polishing fluid.

[0069] Figure 4 A physical picture showing the silicon carbide optical reflector with a complex structure prepared in Example 1; Figure 4 As shown, the silicon carbide material prepared under the process of this embodiment has a denser structure and a smoother surface; the surface roughness is low during the mirror preparation process, and grinding and polishing are easier, which greatly improves production efficiency; on the basis of ensuring optical use requirements and heat dissipation performance, the apparent density of the silicon carbide reflector can be greatly reduced, the goal of lightweighting can be achieved, and the cost of space launch can be reduced.

[0070] Example 2: Figure 2 As shown, an additive manufacturing method for silicon carbide optical reflectors based on green recycled biomass waste is carried out in the following steps:

[0071] Step S1: preparing a corn straw mixed product;

[0072] Corn straw powder with a particle size of 65 μm was recycled as biomass waste as the basic material of 3D printing powder, phenolic resin with a particle size of 47 μm and sodium chloride with a particle size of 2 μm were added, placed in a blade sand mixer, and stirred at 160 °C and a stirring rate of 1200 r / min for 1 h to obtain a corn straw mixed product.

[0073] Step S2: preparing corn straw composite powder;

[0074] The corn straw mixed product was poured into a ball mill and crushed and ball-milled at 80°C with a stirring rate of 600 r / min. After the crushing and ball-milling, it was sieved through a 150-mesh screen to obtain corn straw composite powder as a printing prefabricated material.

[0075] Step S3: printing corn straw biomass embryos;

[0076] The corn straw composite powder was placed in the printing chamber of a selective laser sintering 3D printer, preheated at 70°C, and sintered according to the printer parameters selected according to the pre-designed structural model to obtain a corn straw biomass embryo with a complex solid structure.

[0077] Process parameters: laser power is 25W, scanning speed is 1.5m / s, scanning spacing is 0.11mm, and printing layer thickness is 0.15mm.

[0078] Step S4: preparing a carbon embryo with an optical reflector structure;

[0079] The corn stalk biomass embryo is placed in a tubular furnace, cured at 150°C for 10 hours, and then placed in running water to dissolve the sodium chloride to form micropores; then a protective atmosphere is introduced and heated to 400°C at a heating rate of 2 / min, and kept at 400°C for 1 hour; after the insulation is completed, it is heated to 900°C at a heating rate of 2 / min, and continued to be kept at 900°C for 2 hours; after the insulation is completed, it is cooled with the furnace to obtain a carbon embryo with an optical reflector structure.

[0080] Step S5: preparing a silicon carbide optical reflector;

[0081] The carbon embryo is buried in silicon powder, heated to 1500°C in a vacuum environment, and kept at 1500°C for 2 hours to allow the silicon powder and carbon to fully react. After the reaction, the carbon embryo is cooled in the furnace to obtain a silicon carbide embryo. The silicon carbide embryo is subjected to coarse grinding, fine grinding and polishing in sequence to obtain a silicon carbide optical reflector with a complex structure. The density of silicon carbide formed by reaction sintering in the process of this embodiment can be increased from 2.65g / cm 3 Increased to 3.05g / cm 3 On the basis of ensuring the optical use requirements and heat dissipation performance, the apparent density of the reflector print can be reduced by about 10%.

[0082] For rough grinding, an angle grinder, W40 abrasive and W28 abrasive are selected in sequence to grind until the surface roughness reaches below 1.6μm. For fine grinding, W28 abrasive, W14 abrasive, W10 abrasive and W7 abrasive are selected in sequence to grind to meet the basic requirements of polishing. Polishing is carried out on a polishing machine at a speed of 2500r / min, and the polishing fluid used is diamond polishing fluid.

Claims

1. An additive manufacturing method for silicon carbide optical reflectors based on green recycling of biomass waste, characterized in that The preparation method is carried out according to the following steps: Step S1: preparing a biomass mixed product; The biomass waste, resin and pore-forming agent are mixed, and stirred at 60 to 160° C. for 0.5 to 3 hours to obtain a biomass mixed product; Step S2: preparing biomass composite powder; The biomass mixed product obtained in step S1 is crushed and ball-milled at 40-60° C., and sieved after the crushing and ball-milling to obtain a biomass composite powder; Step S3: printing the biomass embryo; Printing the biomass composite powder obtained in step S2 using additive manufacturing equipment to obtain a biomass embryo; Step S4: preparing a carbon embryo with an optical reflector structure; The biomass embryo obtained in step S3 is placed in a tubular furnace and cured at 60-180° C. for 4-15 hours; then the pore-forming agent is removed by high-temperature decomposition reaction or chemical reaction to form micropores on the surface of the biomass embryo; then a protective atmosphere is introduced and heated to 400-500° C., and the temperature is kept at 400-500° C. for 1-2 hours; after the insulation is completed, it is heated to 800-1000° C., and the temperature is continued to be kept at 800-1000° C. for 1-2 hours; after the insulation is completed, it is cooled with the furnace to obtain a carbon embryo with an optical reflector structure; Step S5: preparing a silicon carbide optical reflector; The carbon embryo obtained in step S4 is buried in silicon powder, heated to 1400-1600° C. in a vacuum environment, and kept warm at 1400-1600° C. for 1-2 hours; after the insulation is completed, it is cooled with the furnace to obtain a silicon carbide embryo; the silicon carbide embryo is ground and polished in sequence to obtain a silicon carbide optical reflector based on green recycled biomass waste.

2. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that The biomass waste described in step S1 is corn straw, wheat straw, rice straw or sawdust waste, with a particle size of 50 to 100 μm; the resin is a thermosetting or thermoplastic resin, including but not limited to polyethersulfone resin or phenolic resin, with a particle size of 20 to 60 μm; the pore-forming agent is ammonium bicarbonate, urea, calcium sulfate or sodium chloride, with a particle size of 2 to 10 μm.

3. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that The stirring rate in step S1 is 600-2800 r / min; the stirring rate of the crushing ball mill in step S2 is 70-670 r / min.

4. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that In step S2, a sieve with 80 to 150 mesh is used for sieving.

5. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that In step S3, the additive manufacturing equipment is a selective laser sintering 3D printer, and the process parameters are: laser power is 10-50W, scanning speed is 1.5-3.5m / s, scanning spacing is 0.05-0.2mm, printing layer thickness is 0.1-0.3mm, and preheating temperature is 50-80℃.

6. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that In step S4, the temperature is heated to 400-500° C. at a heating rate of 1-10° C. / min; after the insulation is completed, the temperature is further heated to 800-1000° C. at a heating rate of 1-10° C. / min.

7. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that The grinding in step S5 is performed by sequentially performing rough grinding and fine grinding.

8. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 7, characterized in that Rough grinding is to select an angle grinder, W40 abrasive and W28 abrasive in sequence to grind until the surface roughness reaches less than 1.6μm.

9. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 7, characterized in that Fine grinding is performed by selecting W28 abrasive, W14 abrasive, W10 abrasive and W7 abrasive in sequence.

10. The additive manufacturing method of silicon carbide optical reflector based on green recycling of biomass waste according to claim 1, characterized in that In step S5, polishing is performed on a polishing machine at a rotation speed of 1500-2500 r / min, and the polishing liquid used is diamond polishing liquid.

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