High-thermal-conductivity graphene optical module shell and preparation method thereof

Abstract

The present application relates to the technical field of optical module accessory preparation, in particular to a high-thermal-conductivity graphene optical module shell and a preparation method thereof, the present application adopts a ceramic composite graphene integrated structure, a ceramic powder and a pore former are mixed to form a compact, the compact is subjected to sectional temperature rising sintering to form a porous ceramic matrix with three-dimensionally connected pores, graphene nanoceramic slurry is filled into the pores of the matrix by vacuum negative pressure impregnation process, and the high-thermal-conductivity graphene optical module shell is prepared by combining sectional gradient drying and curing and finishing processes; the present application forms a three-dimensionally connected porous ceramic framework by sintering, and then fills graphene thermal conductive medium into the pores of the matrix as a whole by vacuum negative pressure, thereby forming a three-dimensionally connected thermal conductive channel that penetrates the whole shell and is continuously interconnected, and there is no interface layering and no dead angle for filling. The product has high and stable overall thermal conductivity, and the heat dissipation performance is greatly improved compared with a traditional aluminum alloy shell, and the product has excellent corrosion resistance and aging resistance.

Description

Technical Field

[0001] This invention relates to the field of optical module component manufacturing technology, specifically to a high thermal conductivity graphene optical module shell and its manufacturing method. Background Technology

[0002] With the rapid development of global digitalization, 5G / 6G mobile communication, cloud computing, big data centers, and high-performance computing, optical modules, as the core components for photoelectric signal conversion in optical communication systems, are rapidly iterating towards ultra-high speed, ultra-high integration, extremely small size, and ultra-large bandwidth. Next-generation high-speed optical modules, represented by 800G and 1.6T, have internal chip power density that is 3–5 times higher than traditional 100G / 400G modules, resulting in a sharp increase in heat generation per unit area. Thermal management has become a key bottleneck restricting the improvement of optical module speed, reliability, and lifespan.

[0003] Currently, the mainstream material used for the casing of high thermal conductivity graphene optical modules in the industry is die-cast aluminum alloy. Although aluminum alloy has a certain thermal conductivity and is easy to process, its thermal conductivity is usually only ≤150 W / (m·K). Faced with the concentrated heat generation of high-density, high-power chips, the heat dissipation efficiency is obviously insufficient, which can easily lead to problems such as excessively high chip junction temperature, increased signal jitter, increased bit error rate, and accelerated device aging. At the same time, aluminum alloy casings have obvious defects: they are prone to creep and dimensional accuracy decay under high temperature conditions, affecting the coupling stability of optical devices; electromagnetic shielding and electrical insulation are difficult to achieve simultaneously, which can easily introduce signal interference in high-frequency and high-speed scenarios; the surface treatment layer is easy to peel off and has limited corrosion resistance, which cannot meet the long-term use requirements of harsh industrial and communication equipment room environments.

[0004] To improve heat dissipation, existing technologies often employ methods such as surface coating with graphene, attaching graphite sheets, adding heat dissipation fins, and microchannel water cooling. However, these methods only create localized heat dissipation structures on the outer surface, and heat still needs to be conducted through multiple interfaces. The high interface thermal resistance and short heat dissipation paths result in limited overall improvement in heat conduction and cannot fundamentally solve the problem of rapid heat dissipation from internal heat sources. Summary of the Invention

[0005] The purpose of this invention is to provide a high thermal conductivity graphene optical module shell and its preparation method, which solves the technical problems of poor thermal conductivity, easy structural deformation, weak anti-interference ability, and insufficient durability of existing aluminum alloy high thermal conductivity graphene optical module shells, as well as the low heat dissipation efficiency of traditional heat dissipation modification schemes and their inability to fundamentally solve the heat dissipation problem of high-speed optical modules.

[0006] The technical problem to be solved by this invention is achieved through the following technical solution: On one hand: This invention provides a method for preparing a high thermal conductivity graphene optical module shell, comprising the following steps: Step S1: Mix ceramic powder with pore-forming agent, then place the mixture into a mold and press it to form a green body; Step S2: The green body is sintered in sections by heating. During the sintering process, the pore-forming agent is decomposed by heat to generate gas and is discharged from the green body to obtain a porous ceramic matrix with an internal interconnected pore structure. Step S3: In a vacuum-sealed environment, graphene nano-ceramic slurry is injected into the internal interconnected pores of the porous ceramic matrix under negative pressure. After impregnation and filling, a ceramic-graphene composite preform is formed. Step S4: Perform segmented drying treatment on the ceramic-graphene composite preform to dehydrate, solidify and shape the graphene nano-ceramic slurry within the pores, forming a ceramic-graphene composite matrix. Step S5: The ceramic-graphene composite matrix is ​​finely processed to obtain a high thermal conductivity graphene optical module shell, which is then tested and packaged.

[0007] Furthermore, the ceramic powder is one or more of silicon oxide, silicon nitride, and aluminum nitride, and the particle size of the ceramic powder is 5-50 μm.

[0008] Furthermore, the pore-forming agent accounts for 10-25% of the total mass of ceramic powder and pore-forming agent, the particle size of the pore-forming agent is 10-500μm, and the porosity of the porous ceramic matrix obtained after sintering is ≥15%.

[0009] Furthermore, in step S3, the vacuum level of the vacuum environment is 10⁻¹ Pa. Under this vacuum condition, negative pressure infiltration is used to fully impregnate and fill the interconnected pores of the porous ceramic matrix with graphene nano-ceramic slurry.

[0010] Furthermore, in step S4, the drying temperature for the segmented drying process is 80-150℃, and the drying time is 10-15 hours. The segmented drying process involves segmented gradient heating to avoid rapid water loss of the graphene nano-ceramic slurry, which could lead to cracking and hollowing defects.

[0011] Furthermore, the segmented heating sintering in step S2 also includes a low-temperature debinding and impurity removal process and a high-temperature crystal densification process, wherein the highest sintering temperature is 1400-1700℃ and the holding time is 2-6 hours.

[0012] Furthermore, the low-temperature debinding and impurity removal process involves a controlled, uniform heating rate of 300–600°C for 1–3 hours. This uniform heating rate allows for the slow pyrolysis of the pore-forming agent and the full volatilization and discharge of organic matter, preventing bubbling, cracking, and pore blockage in the green body. The high-temperature crystallization process continues heating to a set high temperature for sintering after the low-temperature debinding process, with the temperature maintained at 1400–1700°C for 2–6 hours. This promotes the growth of the sintering neck at the ceramic powder particle interface, crystal rearrangement, and densification, while maintaining the three-dimensional interconnected pore structure of the matrix. This balances the mechanical strength of the outer shell structure with the integrity of the thermal conductivity channels for the graphene nano-ceramic slurry.

[0013] On the other hand, the present invention also provides a high thermal conductivity graphene optical module shell, which is prepared by the above preparation method. The high thermal conductivity graphene optical module shell is composed of a porous ceramic matrix and graphene nano-ceramic slurry filled in the pores inside the porous ceramic matrix, and has a thermal conductivity ≥250W / m・K.

[0014] Furthermore, the porous ceramic matrix is ​​formed by pressing ceramic powder with a pore-forming agent into a blank using a mold and then sintering it in stages at elevated temperatures. The ceramic powder is one or more of silicon oxide, silicon nitride, or aluminum nitride.

[0015] Furthermore, the ceramic powder has a particle size of 5~50μm, the pore-forming agent has an addition ratio of 10%~25%, the pore-forming agent has a particle size of 10~500μm, and the porous ceramic matrix has a porosity of ≥15%.

[0016] The beneficial effects of this invention are: (1) This invention forms a three-dimensional, interconnected porous ceramic skeleton by sintering, and then uses vacuum negative pressure to permeate and fill the graphene thermal conductive medium into the overall pores of the matrix, forming a continuous and interconnected three-dimensional thermal conductive channel inside the shell, without interface delamination or dead corners. The product has a high and stable overall thermal conductivity, which greatly improves the heat dissipation performance compared with traditional aluminum alloy shells. It can quickly dissipate the concentrated heat of high-speed optical module chips, significantly reduce chip junction temperature, and reduce signal jitter and transmission error rate.

[0017] (2) The present invention adopts a ceramic matrix composite structure, which is densified by high temperature sintering and crystallization. The structure has strong rigidity and low thermal expansion coefficient. After long-term high and low temperature cycling, the dimensional deviation deformation is small. There is no creep or deformation at high temperature. The dimensional accuracy is stable during long-term operation, which greatly improves the optical path coupling stability and product consistency of high-speed optical modules.

[0018] (3) The porous ceramic matrix of the present invention has excellent intrinsic insulation properties. The graphene composite medium filled in the pores can form a uniform electromagnetic absorption shielding layer. No additional shielding coating is required. The product has high electromagnetic shielding efficiency and can effectively suppress high-frequency electromagnetic crosstalk and signal interference, making it suitable for high-frequency working conditions of ultra-high-speed optical communication.

[0019] (4) The graphene thermal conductive medium of the present invention is embedded in the pores of the ceramic matrix to form an integrated composite structure. There are no problems of surface peeling or wear failure. It has excellent high temperature resistance, moisture resistance, acid and alkali corrosion resistance and thermal shock resistance. It can be adapted to indoor computer rooms, outdoor base stations and harsh industrial scenarios for long-term stable operation, which greatly extends the overall service life of the optical module.

[0020] (5) This invention can be flexibly adapted to the product requirements of multiple scenarios by adjusting the ceramic powder material, powder particle size, pore-forming agent addition ratio, sintering temperature and impregnation parameters. The overall preparation process is mature and controllable, with a high yield of finished products and good production stability. It effectively solves the defects of poor consistency, low yield and unstable performance of traditional modification processes, and has extremely high industrialization and market promotion value. Attached Figure Description

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] Figure 1 This is a schematic flowchart of a method for preparing a high thermal conductivity graphene optical module shell according to the present invention. Figure 2 This is a schematic diagram of steps S1 to S2 of the method for preparing a high thermal conductivity graphene optical module shell according to the present invention. Figure 3 This is a schematic diagram of steps S3 to S5 of the method for preparing a high thermal conductivity graphene optical module shell according to the present invention. Figure 4 This is a cross-sectional schematic diagram of a high thermal conductivity graphene optical module housing according to the present invention.

[0023] Reference numerals: 1. Ceramic powder; 2. Pore-forming agent; 3. Green body; 4. Porous ceramic matrix; 5. Ceramic-graphene composite preform; 6. Ceramic-graphene composite matrix; 7. High thermal conductivity graphene optical module shell; 8. Graphene nano-ceramic slurry. Detailed Implementation

[0024] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0025] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] This invention provides a method for preparing a high thermal conductivity graphene optical module shell. Addressing the shortcomings of existing aluminum alloy high thermal conductivity graphene optical module shells 7, such as low thermal conductivity, poor high-temperature dimensional stability, weak electromagnetic shielding, and insufficient corrosion resistance, as well as the high interface thermal resistance of traditional surface heat dissipation modification methods which cannot fundamentally solve the high-power heat dissipation problem of high-speed optical modules, this invention innovatively adopts a porous ceramic matrix 4 composite graphene nanoceramic structure design. By creating a pore-forming structure and sintering it, three-dimensional interconnected thermally conductive pores are built, followed by vacuum negative pressure impregnation and filling with graphene thermally conductive medium. This completely eliminates the traditional surface heat dissipation structure, constructing a three-dimensional thermally conductive channel that runs through the entire shell, significantly improving the overall thermal conductivity of the high thermal conductivity graphene optical module shell 7. Simultaneously, it considers structural strength, dimensional accuracy, electromagnetic shielding, and weather resistance, making it suitable for the demanding application scenarios of ultra-high-speed optical modules such as 800G and 1.6T.

[0027] like Figure 1 -like Figure 4 As shown, the preparation method of the high thermal conductivity graphene optical module shell of the present invention includes five core steps: pressing and forming of the blank 3, segmented sintering and hole making, vacuum negative pressure graphene nano-ceramic slurry 8 impregnation, segmented drying and curing, and fine processing, testing and packaging. The parameters of each process are precisely controlled to ensure the thermal conductivity, structural stability and yield of the product. The specific details are described below with reference to multiple preferred embodiments.

[0028] Example 1: like Figure 1 -like Figure 3 As shown in the figure, this embodiment discloses a method for preparing a high thermal conductivity graphene optical module shell. The specific preparation steps are as follows: Step S1: Mix ceramic powder 1 with pore-forming agent 2, and then press the mixture into a mold to obtain a green body 3. Specifically, aluminum nitride ceramic powder 1 with a particle size of 5-20μm is selected as the matrix raw material. Aluminum nitride ceramic has the characteristics of ultra-high intrinsic thermal conductivity, excellent insulation, and low high-frequency signal interference, making it suitable for high-speed optical communication high-frequency operating scenarios. Starch is selected as pore-forming agent 2, and the particle size of pore-forming agent 2 is controlled at 50-100μm to facilitate the formation of uniform interconnected pores after sintering. According to the mass ratio, pore-forming agent 2 accounts for 15% of the total mass of ceramic powder 1 and pore-forming agent 2. The precisely proportioned aluminum nitride ceramic powder 1 and starch pore-forming agent 2 are put into a high-speed powder mixer and mixed at a uniform speed for 30 minutes to ensure that the particles of the two raw materials are uniformly dispersed without agglomeration or stratification, thus avoiding uneven pore distribution during subsequent sintering. After mixing, the mixed powder is placed into a custom high thermal conductivity graphene optical module shell 7 mold and cold isostatic pressing is used. The pressing pressure is set to 25MPa and the holding time is 5min. The pressing process yields a blank 3 with a complete structure and uniform density. The outer dimensions of the blank 3 match the standard 400G / 800G high thermal conductivity graphene optical module shell 7 specifications, without any missing corners, cracks, or deformation defects.

[0029] Step S2: The green body 3 is sintered in stages with increasing temperature. During the sintering process, the pore-forming agent 2 decomposes upon heating, generating gas that is discharged from the green body 3, resulting in a porous ceramic matrix 4 with interconnected pore structures. Specifically, the formed green body 3 is placed in a high-temperature sintering furnace, and a staged heating sintering process is adopted with precise temperature control throughout. The process is divided into two stages: low-temperature debinding and impurity removal, and high-temperature crystalline densification. The first stage is low-temperature debinding and impurity removal, where the temperature is increased from room temperature to 450℃ at a uniform rate of 2℃ / min and held at a constant temperature for 2 hours. This gradual and stable heating rate allows the starch pore-forming agent 2 in the green body 3 to slowly decompose upon heating, and the organic matter inside the green body 3 is completely volatilized and discharged. This effectively avoids the problem of bubbling, cracking, and pore blockage caused by the rapid pyrolysis of the pore-forming agent 2 generating a large amount of gas. At the same time, it removes trace impurities mixed in during the raw material mixing process, ensuring the purity of the green body 3. After low-temperature debinding, the second stage, high-temperature crystallization, begins. The temperature is increased to 1550℃ at a rate of 3℃ / min and held at this temperature for 4 hours. This temperature and holding time promote the formation of sintering necks at the aluminum nitride ceramic particle interface, achieving crystal phase rearrangement and microstructure densification, thus improving the mechanical strength of the matrix. Simultaneously, the three-dimensional interconnected pore structure within the green body 3 is fully preserved, ensuring unobstructed filling channels for the subsequent graphene nano-ceramic slurry 8. After sintering, the matrix is ​​naturally cooled to room temperature in the furnace, ultimately yielding a porous aluminum nitride ceramic matrix with a porosity of 18%, a pore connectivity rate ≥95%, and no closed dead-angle pores.

[0030] Step S3: Under a vacuum-sealed environment, graphene nano-ceramic slurry 8 is injected into the interconnected pores of the porous ceramic substrate 4 under negative pressure, forming a ceramic-graphene composite preform 5 after impregnation and filling. Specifically, the prepared porous ceramic substrate 4 is placed inside a vacuum impregnation device, the device cavity is sealed, the vacuum unit is started to evacuate the vacuum, and the vacuum degree of the cavity is stably maintained at 10 Pa for 30 minutes to completely remove the air inside the pores of the porous ceramic substrate 4, eliminating the impregnation dead zones and interface voids caused by air obstruction. Subsequently, graphene nano-ceramic slurry 8 is injected into the cavity through a negative pressure feeding system. The graphene nano-ceramic slurry 8 is composed of graphene nanosheets, ceramic binder, dispersant and deionized water, and has excellent fluidity and strong permeability. Under negative pressure, the graphene nano-ceramic slurry 8 rapidly and fully impregnates and fills all the interconnected pores of the porous ceramic matrix 4. This impregnation continues for 90 minutes, ensuring that the graphene nano-ceramic slurry 8 is fully filled, without voids or delamination, forming a uniformly structured ceramic-graphene composite preform 5. This vacuum negative pressure impregnation method completely solves the drawbacks of traditional manual brushing and surface bonding methods, such as shallow penetration, uneven filling, and high interfacial thermal resistance of the graphene nano-ceramic slurry 8, thus constructing a continuous thermally conductive network throughout the entire matrix.

[0031] Step S4: The ceramic-graphene composite preform 5 is subjected to segmented drying treatment to dehydrate and solidify the graphene nano-ceramic slurry 8 within the pores, forming the ceramic-graphene composite matrix 6. Specifically, the impregnated ceramic-graphene composite preform 5 is smoothly removed and placed in a constant temperature drying device. A segmented gradient heating drying process is adopted to avoid cracking, hollowing, and detachment defects caused by rapid surface water loss and internal water retention in the graphene nano-ceramic slurry 8. First, the initial drying temperature is set to 80℃ and dried at a constant temperature for 4 hours to slowly evaporate the free water inside the graphene nano-ceramic slurry 8. Then, the temperature is uniformly increased to 110℃ and dried at a constant temperature for 5 hours to remove the bound water inside the pores. Finally, the temperature is increased to 140℃ and dried at a constant temperature for 4 hours to completely solidify the graphene nano-ceramic slurry 8, allowing the graphene nano-ceramic slurry 8 to be stably formed within the porous ceramic pores and tightly adhered to the ceramic pore walls, forming an integrated ceramic-graphene composite matrix 6. The total drying time is 13 hours. After drying, the graphene thermal conductive medium is evenly distributed in the three-dimensional pores of the matrix, forming a continuous three-dimensional thermal conductive channel.

[0032] Step S5: The ceramic-graphene composite substrate 6 is precision machined to obtain the high thermal conductivity graphene optical module shell 7, and finally inspected and packaged. Specifically, the dried and cured ceramic-graphene composite substrate 6 is precision machined. Through CNC grinding, precision milling and chamfering processes, the slight dimensional deviations generated during sintering and drying are corrected to ensure that the flatness and dimensional accuracy of the shell meet the optical module assembly standards, and the shell surface is smooth without burrs, cracks and uneven defects.

[0033] After the finishing process, the high thermal conductivity graphene optical module shell 7 is subjected to comprehensive performance testing, including thermal conductivity testing, dimensional accuracy testing, mechanical strength testing, electromagnetic shielding performance testing, and high and low temperature aging resistance testing. After passing the tests, it is dusted, cleaned, and sealed. The high thermal conductivity graphene optical module shell 7 mainly comprises a porous ceramic substrate 4 and a graphene nano-ceramic slurry 8 that is filled and solidified in the pores inside the porous ceramic substrate 4.

[0034] The high thermal conductivity graphene optical module shell 7 prepared in this embodiment, after testing with professional equipment, has a thermal conductivity of up to 285 W / (m·K), a bending strength of ≥180 MPa, and after 500 hours of cyclic aging at high temperature of 85℃ and low temperature of -40℃, the dimensional deviation is ≤0.02 mm, with no deformation, cracking, or coating peeling. The electromagnetic shielding effectiveness is ≥45 dB, which can effectively solve the problem of concentrated heat generation in ultra-high speed optical module chips, reduce chip bit error rate, and extend device life.

[0035] Example 2: like Figure 1 -like Figure 3 As shown, this embodiment discloses a method for preparing a high thermal conductivity graphene optical module shell. The basic steps are the same as in Embodiment 1, with the difference being the fine adjustment of the raw material ratio and process parameters, as detailed below: In step S1, silicon nitride ceramic powder 1 with a particle size of 20-50 μm is selected, and ammonium bicarbonate is selected as the pore-forming agent 2 with a particle size of 200-300 μm. The pore-forming agent 2 accounts for 20% of the total mass of ceramic powder 1 and pore-forming agent 2. The mixing time is 40 min, the pressing pressure is 30 MPa, and the pressure is held for 6 min.

[0036] In step S2, the segmented sintering process, the low-temperature debinding section is heated at a rate of 1.5℃ / min to 500℃ and held for 2.5h; the high-temperature densification section is heated to 1600℃ and held for 5h, resulting in a porous ceramic matrix with a porosity of 22%.

[0037] In step S3, the vacuum degree of the vacuum impregnation chamber is maintained at 5×10 Pa, and the impregnation time is 120 min to ensure that the large-pore pores are fully filled with graphene nano-ceramic slurry 8.

[0038] In step S4, the impregnated ceramic graphene composite preform 5 is steadily removed and placed in a constant temperature drying device. In this embodiment, the segmented drying process is divided into three stages: drying at 80℃ for 3 hours, drying at 120℃ for 5 hours, and drying at 150℃ for 5 hours, with a total drying time of 13 hours.

[0039] The first step involves drying at 80℃ for 3 hours to remove most of the free water.

[0040] Second stage: Heat to 120℃ and dry for 5 hours to promote gelation and initial curing.

[0041] The third step involves heating to 150°C and drying for 5 hours to completely dehydrate and solidify the graphene nano-ceramic slurry 8, forming a ceramic graphene composite matrix 6.

[0042] The total drying time is 13 hours. Gradient heating can effectively avoid cracking of the ceramic-graphene composite matrix 6 or slurry delamination defects caused by rapid moisture vaporization.

[0043] The high thermal conductivity graphene optical module shell 7 prepared in this embodiment has higher porosity and a larger amount of graphene thermal conductive medium filling. The thermal conductivity can reach 310 W / (m·K) after testing. It has excellent mechanical strength, stronger high temperature creep resistance, and is suitable for the harsh heat dissipation scenarios of 1.6T ultra-high speed and ultra-high power consumption optical modules. Its resistance to acid, alkali and humidity corrosion in computer rooms is greatly improved.

[0044] Example 3: like Figure 1 -like Figure 3 As shown, this embodiment discloses a method for preparing a high thermal conductivity graphene optical module shell. The basic steps are the same as in Embodiment 1, except that a composite ceramic powder bulk material is used, as detailed below: In step S1, silicon oxide and aluminum nitride composite ceramic powder 1 is selected with a mass ratio of 1:1 and a powder particle size of 10-30μm. The pore-forming agent 2 is lignin with a particle size of 100-200μm and an addition ratio of 10%. The mixing time is 35min, the pressing pressure is 20MPa, and the holding pressure is 5min.

[0045] Step S2 sintering process: low temperature section 350℃ for 3h, heating rate 1℃ / min; high temperature section 1450℃ for 3h, to produce a porous ceramic matrix with a porosity of 15%.

[0046] Step S3 maintains a vacuum of 10 Pa and an impregnation time of 80 min; Step S4 uses a three-stage gradient drying process at 80℃, 100℃ and 130℃, with a total time of 10 h.

[0047] This embodiment has lower raw material costs, lower energy consumption in the manufacturing process, and a thermal conductivity of up to 255 W / (m·K), which meets the conventional heat dissipation requirements of 800G optical modules. At the same time, it has excellent electrical insulation and dimensional stability, making it suitable for mass production.

[0048] Example 4: like Figure 1 -like Figure 3As shown, this embodiment discloses a method for preparing a high thermal conductivity graphene optical module shell. The basic process flow is consistent with that of Embodiment 1, and it is specifically adapted to the application scenario of industrial-grade high-temperature resistant 1.6T optical modules. The specific process parameters are as follows: Step S1: Select silicon nitride ceramic powder 1 with a particle size of 30-50μm, and polyethylene glycol micro powder 2 with a particle size of 300-500μm. The pore-forming agent 2 accounts for 25% of the total powder mass. Put the powder into a powder mixer and mix continuously for 45 minutes to ensure that the powder does not agglomerate. Use cold isostatic pressing process, pressing pressure of 35MPa, holding pressure for 7 minutes, to obtain a dense and flat green body 3.

[0049] Step S2: Segmented sintering treatment. In the low-temperature debinding section, the temperature is increased to 600℃ at a rate of 1.2℃ / min and held at a constant temperature for 1 hour to fully decompose and volatilize the polymer pore-forming agent 2 and impurities. Then, the temperature is increased to 1700℃ at a rate of 2.5℃ / min and held at a constant temperature for 6 hours. Under the premise of ensuring the mechanical strength of the ceramic matrix, a large-pore-size, highly interconnected pore structure is constructed, and finally a porous silicon nitride ceramic matrix with a porosity of 25% is obtained.

[0050] Step S3: Place the substrate in a vacuum impregnation device, stabilize the vacuum at 10 Pa, and continue vacuuming for 40 minutes. Then inject the graphene nano-ceramic slurry 8 and impregnate under negative pressure for 120 minutes to ensure that the large pores and micro pores are fully filled and saturated.

[0051] Step S4: Segmented gradient drying, constant temperature at 80℃ for 3 hours, constant temperature at 120℃ for 4 hours, and constant temperature at 150℃ for 6 hours, with a total drying time of 13 hours, slowly removing 8% moisture from the graphene nano-ceramic slurry, and preventing problems such as matrix cracking and pore delamination.

[0052] Step S5: After precision milling, grinding, and deburring, the performance testing and packaging are completed. The shell prepared in this embodiment has a thermal conductivity of up to 320 W / (m·K), a bending strength of 175MPa, and excellent high temperature resistance and thermal shock resistance. It can be adapted to the long-term operation of 1.6T high-speed optical modules in harsh working conditions such as industrial high-temperature computer rooms and outdoor base stations.

[0053] Example 5: like Figure 1 -like Figure 3 As shown, this embodiment discloses a method for preparing a high thermal conductivity graphene optical module shell, suitable for mass production of commercially viable 800G optical modules. The process parameters are as follows: Step S1: Select silica ceramic powder 1 with a particle size of 5-30μm as a low-cost matrix raw material. Select starch as pore-forming agent 2 with a particle size of 50-200μm. The mass ratio of pore-forming agent 2 is 12%. Mix the powder for 30 minutes, press at a pressure of 22MPa, and hold for 5 minutes to complete the molding of the green body 3.

[0054] Step S2: In the low-temperature section, the temperature is increased to 400℃ at 2℃ / min and held for 2 hours to complete the removal of adhesive and impurities; in the high-temperature section, the temperature is increased to 1400℃ and held for 2 hours to sinter and form a porous silica ceramic matrix with a porosity of 16%.

[0055] Step S3: Maintain the vacuum level of the cavity at 10 Pa, evacuate for 30 min, and impregnate the graphene nano-ceramic slurry under negative pressure for 890 min.

[0056] Step S4: A segmented drying process is adopted, which involves drying at 80℃ for 4 hours, at 110℃ for 4 hours, and at 140℃ for 3 hours, for a total duration of 11 hours, to efficiently complete the curing and shaping of the graphene nano-ceramic slurry.

[0057] Step S5: After fine processing and inspection, the product is packaged and stored. This embodiment uses low-cost raw materials, has a low sintering temperature, and low production energy consumption. The finished product has a thermal conductivity of up to 260 W / (m·K), a dimensional deviation of ≤0.02mm, and an electromagnetic shielding performance of ≥42dB. It fully meets the requirements of heat dissipation, anti-interference, and long service life of 800G optical modules in commercial data centers, and has a very high cost-performance ratio for mass production.

[0058] Comparative Example 1 (Traditional Aluminum Alloy Casing) The high thermal conductivity graphene optical module shell 7, made of commonly used die-cast aluminum alloy, was selected and manufactured using conventional processes. However, its thermal conductivity was only 135 W / (m·K). After continuous operation at 85℃ for 72 hours, the shell exhibited slight creep, a dimensional deviation of 0.12 mm, decreased optical device coupling accuracy, and a significant increase in signal error rate. At the same time, electromagnetic interference was significant in high-frequency operating scenarios, and the surface anodized layer showed slight peeling after 3 months in a humid computer room environment, indicating poor corrosion resistance.

[0059] Comparative Example 2 (Traditional aluminum alloy shell with surface graphene coating) Using traditional processes, a graphene heat dissipation coating is sprayed onto the surface of the die-cast aluminum alloy high thermal conductivity graphene optical module shell 7, with a coating thickness of 0.05mm. Testing revealed that the overall thermal conductivity of the product is only 160 W / (m·K), with only the surface layer possessing heat dissipation capabilities. The thermal conductivity of the shell substrate is not significantly improved, heat cannot be quickly dissipated from the internal chip, and the multi-layered interface results in high thermal resistance. After prolonged high-temperature operation, the surface graphene coating is prone to wear and peeling, leading to a rapid decline in heat dissipation performance and making it unsuitable for the long-term stable operation requirements of ultra-high-speed optical modules.

[0060] Product Structure and Performance Principles Explanation The high thermal conductivity graphene optical module shell 7 prepared by this invention is an integrated structure of porous ceramic matrix 4 and graphene composite, rather than a simple surface modification. The porous ceramic matrix 4 forms a three-dimensional interconnected network pore structure through precise pore-forming and sintering. The pores are evenly distributed throughout the shell without local voids or defects. The graphene nano-ceramic slurry 8 fills all the pores under vacuum negative pressure conditions. After curing, it is tightly bonded to the ceramic matrix without interface gaps or delamination. This creates a continuous three-dimensional thermally conductive network throughout the shell, completely breaking through the technical bottlenecks of traditional heat dissipation structures, which only dissipate heat from the surface, have high interface thermal resistance, and short heat dissipation paths.

[0061] The ceramic matrix boasts advantages such as high strength, high dimensional stability, high insulation, resistance to high and low temperatures, and corrosion resistance, overcoming the shortcomings of aluminum alloy shells, including high-temperature creep, poor dimensional accuracy, and the difficulty in simultaneously achieving insulation and shielding. The graphene medium filling the pores possesses an ultra-high intrinsic thermal conductivity, enabling rapid conduction of the concentrated heat generated by the optical module chip. Heat is directly diffused to the entire shell through the internal three-dimensional heat conduction channels without needing to pass through multiple interfaces, and then dissipated to the external environment, significantly improving heat dissipation efficiency. Simultaneously, the ceramic-graphene composite structure achieves a precise balance between electromagnetic shielding and electrical insulation in high-frequency scenarios, effectively suppressing high-speed signal jitter and interference, and significantly reducing the bit error rate of the optical module.

[0062] Comparison of the performance of each embodiment with existing technology To directly verify the technical superiority of the preparation method and product of this invention, a unified testing standard (room temperature 25℃, standard atmospheric pressure, high-frequency 100G-1.6T optical communication operating conditions) was used to conduct comprehensive performance testing on the products of Examples 1-5, Comparative Example 1, and Comparative Example 2. The core performance data comparison is shown in the table below: As shown in the table above, the high thermal conductivity graphene optical module shell 7 prepared by the five embodiments of the present invention exhibits a more than 90% improvement in thermal conductivity and a 30% or more improvement in electromagnetic shielding effectiveness compared to traditional aluminum alloy shells and surface-modified shells. High-temperature creep and dimensional deformation are also significantly reduced. Simultaneously, it retains the excellent mechanical strength and weather resistance of the ceramic composite structure, solving core pain points in existing technologies such as poor heat dissipation, low precision, signal interference, and easy aging and detachment. Furthermore, different embodiments can be adapted to various application scenarios, including commercial, industrial, and high-end ultra-high-speed applications, demonstrating high process flexibility and broad coverage, possessing strong technological innovation and industrialization value.

[0063] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high thermal conductivity graphene optical module shell, characterized in that, Includes the following steps: Step S1: Mix ceramic powder with pore-forming agent, then place the mixture into a mold and press it to form a green body; Step S2: The green body is sintered in sections by heating. During the sintering process, the pore-forming agent is decomposed by heat to generate gas and is discharged from the green body to obtain a porous ceramic matrix with an internal interconnected pore structure. Step S3: In a vacuum-sealed environment, graphene nano-ceramic slurry is injected into the internal interconnected pores of the porous ceramic matrix under negative pressure. After impregnation and filling, a ceramic-graphene composite preform is formed. Step S4: Perform segmented drying treatment on the ceramic-graphene composite preform to dehydrate, solidify and shape the graphene nano-ceramic slurry within the pores, forming a ceramic-graphene composite matrix. Step S5: The ceramic-graphene composite matrix is ​​finely processed to obtain a high thermal conductivity graphene optical module shell, which is then tested and packaged.

2. The preparation method according to claim 1, characterized in that, The ceramic powder is one or more of silicon oxide, silicon nitride, and aluminum nitride, and the particle size of the ceramic powder is 5-50 μm.

3. The preparation method according to claim 1, characterized in that, The pore-forming agent accounts for 10-25% of the total mass of ceramic powder and pore-forming agent, the particle size of the pore-forming agent is 10-500μm, and the porosity of the porous ceramic matrix obtained after sintering is ≥15%.

4. The preparation method according to claim 1, characterized in that, In step S3, the vacuum level of the vacuum environment is 10⁻¹ Pa. Under this vacuum condition, negative pressure infiltration is used to fully impregnate and fill the interconnected pores of the porous ceramic matrix with graphene nano-ceramic slurry.

5. The preparation method according to claim 1, characterized in that, In step S4, the drying temperature for the segmented drying process is 80-150℃, and the drying time is 10-15 hours. The segmented drying process involves segmented gradient temperature increases.

6. The preparation method according to claim 1, characterized in that, Step S2, segmented heating sintering, also includes a low-temperature debinding and impurity removal process and a high-temperature crystal densification process. The highest sintering temperature is 1400-1700℃, and the holding time is 2-6 hours.

7. The preparation method according to claim 6, characterized in that, The low-temperature debinding and impurity removal process involves heating at a controllable rate at a constant temperature of 300–600°C for 1–3 hours. The high-temperature crystal densification process continues to heat to a set high temperature for sintering after the low-temperature debinding process is completed, at a temperature of 1400–1700°C for 2–6 hours.

8. A high thermal conductivity graphene optical module shell, prepared by the preparation method according to any one of claims 1-7, characterized in that, The high thermal conductivity graphene optical module shell is composed of a porous ceramic matrix and graphene nano-ceramic slurry filling the pores inside the porous ceramic matrix, with a thermal conductivity ≥250W / m・K.

9. The high thermal conductivity graphene optical module housing according to claim 8, characterized in that, The porous ceramic matrix is ​​formed by pressing ceramic powder with a pore-forming agent into a blank through a mold and sintering it in stages at elevated temperatures. The ceramic powder is one or more of silicon oxide, silicon nitride, or aluminum nitride.

10. The high thermal conductivity graphene optical module housing according to claim 9, characterized in that, The ceramic powder has a particle size of 5~50μm, the pore-forming agent has an addition ratio of 10%~25%, the pore-forming agent has a particle size of 10~500μm, and the porous ceramic matrix has a porosity of ≥15%.

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