Production method of graphite pipe with high thermal conductivity

Abstract

The production method comprises the following specific steps that S1, raw material mixing is conducted, specifically, raw materials needed by a high-thermal-conductivity graphite pipe body are taken and evenly mixed according to a certain proportion, and the raw materials comprise carbon nanofibers, graphene oxide, 99.9% high-purity graphite powder, ceramic particles and a sintering aid; s2, manufacturing a pipe blank: manufacturing the graphite pipe blank by using the mixed raw materials; s3, resin impregnation is conducted, specifically, needed resin is blended, impregnation of the resin and the pipe blank is completed in a negative pressure environment, and pores of the graphite pipe blank are filled with the resin; and S4, curing: putting the resin-impregnated graphite tube blank into a curing machine, pre-curing for 11 hours at 120 DEG C, and then heating to 150 DEG C to complete a cross-linking reaction. The production method of the high-thermal-conductivity graphite tube disclosed by the invention has the technical effect of synchronously improving the thermal conductivity, compactness and mechanical stability of the graphite tube.

Description

Technical Field

[0001] This invention relates to the field of graphite tube manufacturing technology, and in particular to a method for manufacturing high thermal conductivity graphite tubes. Background Technology

[0002] Graphite tubes are widely used in electrode materials, thermal management devices, and composite material reinforcement phases due to their excellent electrical conductivity, thermal conductivity, and chemical stability. However, their inherent brittleness severely limits their reliability and durability in practical applications.

[0003] The layered structure of graphite means that the layers are bound together only by van der Waals forces, making it prone to interlayer slippage and fracture under shear or impact loads. Furthermore, internal defects (such as porosity and cracks) generated during the high-temperature graphitization process further reduce mechanical properties. While traditional modification methods (such as resin impregnation) can partially improve toughness, they do not significantly enhance fracture resistance. Summary of the Invention

[0004] This invention discloses a method for producing high thermal conductivity graphite tubes, aiming to solve the technical problem that although traditional modification methods (such as resin impregnation) can partially improve toughness, their fracture resistance cannot be significantly improved.

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

[0006] A method for producing a high thermal conductivity graphite tube includes the following specific steps:

[0007] S1: Raw material mixing: Take the raw materials required for the high thermal conductivity graphite tube body and mix them evenly in a certain proportion. The raw materials include nano carbon fiber, graphene oxide, 99.9% high-purity graphite powder, ceramic particles and sintering aids.

[0008] S2: Tube blank production: The production of graphite tube blanks is achieved by using well-mixed raw materials;

[0009] S3: Resin impregnation: Prepare the required resin and use a negative pressure environment to impregnate the resin with the tube blank, so that the resin fills the pores of the graphite tube blank.

[0010] S4: Curing: Place the resin-impregnated graphite tube blank in a curing machine and pre-cur it at 120°C for 11 hours, then raise the temperature to 150°C to complete the cross-linking reaction;

[0011] S5: High-temperature sintering: Sintering the cured graphite tube in a high-temperature environment;

[0012] S6: Post-processing: After machining processes such as turning and grinding, and assembly of parts, graphite tubes are produced;

[0013] S1, the raw material mixing includes the following specific steps:

[0014] S11: Raw material premixing: Premixing carbon nanofibers with graphene oxide;

[0015] S12: Raw material ball milling and mixing; 99.9% high-purity graphite powder, nano-carbon fiber mixture and ceramic particles are mixed in the required proportion, and then activated by ball milling to form a composite substrate;

[0016] S13: Addition of sintering aid: Add 5wt% boric acid as a sintering aid and mix it through a second ball milling process; In S11, the mass ratio of graphene oxide to carbon nanofiber in the raw material premix is ​​0.075wt%:1; In S12, the diameter of carbon nanofiber in the raw material ball milling process is 50-100nm, and the mass ratio of 99.9% high-purity graphite powder, carbon nanofiber, and ceramic particles is 6:2:2.

[0017] By adding carbon nanofibers, graphene oxide, ceramic particles, and sintering aids to ordinary graphite and resin raw materials, the overall performance of graphite tubes can be greatly improved. Among them, the addition of graphene oxide and carbon nanofibers can greatly improve the tensile strength and reduce the brittle defects of graphite tubes. The addition of ceramic particles, after being combined with graphite, provides both thermal conductivity and mechanical stability, thereby achieving a simultaneous improvement in the thermal conductivity, density, and mechanical stability of graphite tubes.

[0018] In a preferred embodiment, the graphite tube in S6 includes: a graphite tube body; an inner heat-conducting mechanism disposed on the inner circumferential wall of the graphite tube body; a plurality of T-slots disposed at equal intervals around the outer circumferential wall of the graphite tube body; and a plurality of support mechanisms respectively installed in the plurality of T-slots.

[0019] Each of the support mechanisms includes: two support shafts arranged symmetrically, each support shaft having a groove, and L-shaped brackets fixedly connected to the outer walls of opposite sides of the two support shafts; and multiple U-shaped metal plates fixedly connected to the outer circumferential walls of the two support shafts and movably fitted against the inner wall of the T-shaped groove.

[0020] Each of the support mechanisms further includes: a sleeve, which is movably fitted onto the outer circumferential wall of the two support shafts, and a through hole is provided through one inner wall of the sleeve; a support rod, which is movably inserted into the through hole, and an arc-shaped support plate is fixedly connected to the outer side of the support rod.

[0021] Each of the support mechanisms further includes: a T-shaped bracket, fixedly connected to the inner end of the support rod, and each end of the T-shaped bracket is provided with a slot, and two L-shaped brackets are respectively movably engaged in the slots; and two connecting plates, symmetrically fixedly connected to the inner circumference of the sleeve.

[0022] Each of the support mechanisms further includes: two insert rods, which are respectively fixedly connected to the outer walls of the two connecting plates on opposite sides and are correspondingly inserted into the grooves of the two support shafts; two circular support plates, which are respectively fixedly connected to the opposite ends of the two insert rods, and a spring is fixedly connected between the inner wall of the groove and the circular support plate, and the spring surrounds the insert rod.

[0023] The structure incorporates a support mechanism, primarily designed to provide longitudinal support within the T-slot. The T-slot design increases surface area, enhancing heat exchange efficiency and dispersing surface stress concentration to prevent localized overload. The radial preload generated by the elastic compression of the U-shaped metal sheet counteracts the tensile stress within the graphite, reducing the probability of crack initiation. Furthermore, the retraction and ejection mechanisms ensure that the support mechanism only ejects outwards when it reaches the inner installation position, achieving a positioning function and reducing installation difficulty. This also ensures the support mechanism is stably supported within the T-slot, eliminating the need for secondary glue fixation.

[0024] In a preferred embodiment, the internal heat conduction mechanism includes: a spiral heat conduction channel one, fixedly connected to the inner circumferential wall of the graphite tube body; and a spiral heat conduction channel two, fixedly connected to the inner circumferential wall of the graphite tube body. The spiral heat conduction channel one and the spiral heat conduction channel two are symmetrically arranged and can be intersected in multiple ways.

[0025] The internal heat conduction mechanism further includes: multiple intersection points located at multiple intersection positions of the first spiral heat conduction channel and the second spiral heat conduction channel; and multiple nanocone arrays fixedly connected to the multiple intersection points respectively.

[0026] By incorporating an internal heat-conducting mechanism and forming spiral heat-conducting channels one and two on the inner wall of the graphite tube body, the heat-conducting area can be increased and the heat-conducting efficiency optimized. Furthermore, by setting a nanocone array at the intersection of spiral heat-conducting channels one and two, the heat-conducting efficiency can be optimized to a great extent.

[0027] As can be seen from the above, a method for producing a high thermal conductivity graphite tube includes the following specific steps: S1: Raw material mixing: Take the raw materials required for the main body of the high thermal conductivity graphite tube and mix them evenly in a certain proportion. The raw materials include nano-carbon fiber, graphene oxide, 99.9% high-purity graphite powder, ceramic particles, and sintering aids; S2: Tube blank preparation: Use the mixed raw materials to prepare the graphite tube blank; S3: Resin impregnation: Prepare the required resin and use a negative pressure environment to impregnate the resin with the tube blank, so that the resin fills the pores of the graphite tube blank; S4: Curing: Place the resin-impregnated graphite tube blank in a curing machine and pre-cur it at 120℃ for 11 hours, then raise the temperature to 150℃ to complete the cross-linking reaction; S5: High-temperature sintering: Sinter the cured graphite tube in a high-temperature environment; S6: Post-processing: After machining... After machining processes such as cutting and grinding, and assembly of parts, graphite tubes are manufactured. Step S1, raw material mixing, includes the following specific steps: S11: Raw material premixing: Premixing carbon nanofibers with graphene oxide; S12: Raw material ball milling mixing: Mixing 99.9% high-purity graphite powder, carbon nanofiber mixture, and ceramic particles in the required proportion, and forming a composite substrate after ball milling activation; S13: Adding sintering aid: Adding 5wt% boric acid as a sintering aid, and then ball milling again; In step S11, the mass ratio of graphene oxide to carbon nanofibers in the raw material premixing is 0.075wt%:1; In step S12, the diameter of the carbon nanofibers in the raw material ball milling mixing is 50-100nm, and the mass ratio of 99.9% high-purity graphite powder, carbon nanofibers, and ceramic particles is 6:2:2. The high thermal conductivity graphite tube production method provided by this invention has the technical effect of simultaneously improving the thermal conductivity, density, and mechanical stability of graphite tubes. Attached Figure Description

[0028] Figure 1 This is an overall flow chart of a high thermal conductivity graphite tube production method proposed in this invention.

[0029] Figure 2 This is a flow chart of the raw material mixing process for a high thermal conductivity graphite tube production method proposed in this invention.

[0030] Figure 3 This is a schematic diagram of the overall structure of a graphite tube according to the high thermal conductivity graphite tube production method proposed in this invention.

[0031] Figure 4 This is a schematic diagram of the inner wall structure of a graphite tube according to the high thermal conductivity graphite tube production method proposed in this invention.

[0032] Figure 5 This is a schematic diagram showing the breakdown of the support structure for a high thermal conductivity graphite tube production method proposed in this invention.

[0033] In the diagram: 1. Graphite tube body; 2. Internal heat conduction mechanism; 3. Support mechanism; 4. T-slot; 201. Spiral heat conduction channel one; 202. Spiral heat conduction channel two; 203. Nanocone array; 204. Intersection point; 301. U-shaped metal sheet; 302. Support shaft; 303. Groove; 304. L-shaped bracket; 305. Arc-shaped support plate; 306. Support rod; 307. T-shaped bracket; 308. Circular support plate; 309. Spring; 310. Insert rod; 311. Connecting plate; 312. Perforation; 313. Sleeve. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0035] The high thermal conductivity graphite tube production method disclosed in this invention is mainly applied to the production of graphite tubes.

[0036] Reference Figure 1 and Figure 2 A method for producing a high thermal conductivity graphite tube includes the following specific steps:

[0037] S1: Raw material mixing: Take the raw materials required for the main body of the high thermal conductivity graphite tube and mix them evenly in a certain proportion. The raw materials include nano carbon fiber, graphene oxide, 99.9% high-purity graphite powder, ceramic particles and sintering aids. By adding nano carbon fiber, graphene oxide, ceramic particles and sintering aids to ordinary graphite and resin raw materials, the overall performance of the graphite tube can be greatly improved.

[0038] S2: Tube blank production: The production of graphite tube blanks is achieved by using well-mixed raw materials;

[0039] S3: Resin impregnation: Prepare the required resin and use a negative pressure environment to impregnate the resin with the tube blank, so that the resin fills the pores of the graphite tube blank.

[0040] S4: Curing: Place the resin-impregnated graphite tube blank in a curing machine and pre-cur it at 120°C for 11 hours, then raise the temperature to 150°C to complete the cross-linking reaction;

[0041] S5: High-temperature sintering: Sintering the cured graphite tube in a high-temperature environment;

[0042] S6: Post-processing: After machining processes such as turning and grinding, and assembly of parts, graphite tubes are produced;

[0043] S1, Raw material mixing includes the following specific steps:

[0044] S11: Raw material premixing: Nanofiber carbon and graphene oxide are premixed. By adding graphene oxide, the tensile strength of carbon fiber can be increased by 225% and the Young's modulus can be increased by 184%. Its polar functional groups can also improve the bonding force with the matrix such as resin and reduce the brittle defects of graphite tube.

[0045] S12: Raw material ball milling and mixing; 99.9% high-purity graphite powder, nano-carbon fiber mixture and ceramic particles are mixed in the required proportion, and after ball milling and activation, a composite substrate is formed. The ceramic particles are designed based on their excellent thermal conductivity and hardness, and can fill the pores inside the graphite tube to improve density. After being combined with graphite, they have both thermal conductivity and mechanical stability, thereby achieving a simultaneous improvement in the thermal conductivity, density and mechanical stability of the graphite tube.

[0046] S13: Addition of sintering aid: Add 5wt% boric acid as a sintering aid and mix it through a second ball mill. In addition, the addition of 5wt% boric acid as a sintering aid can greatly reduce the hot pressing temperature and reduce production energy consumption.

[0047] S11, in the raw material premix, the mass ratio of graphene oxide to carbon nanofiber is 0.075wt%:1;

[0048] In S12, during the ball milling and mixing of raw materials, the diameter of the carbon nanofibers is 50-100nm, and the mass ratio of 99.9% high-purity graphite powder, carbon nanofibers, and ceramic particles is 6:2:2.

[0049] Reference Figure 3 In a preferred embodiment, the graphite tube in S6 includes:

[0050] Graphite tube body 1;

[0051] The internal heat conduction mechanism 2 is located on the inner circumference of the graphite tube body 1;

[0052] Multiple T-shaped grooves 4 are equidistantly arranged around the outer periphery of the graphite tube body 1;

[0053] Multiple support mechanisms 3 are installed in multiple T-slots 4 respectively.

[0054] Reference Figure 4 In a preferred embodiment, the internal heat-conducting mechanism 2 includes:

[0055] Spiral heat conduction channel 201 is fixedly connected to the inner circumference of the graphite tube body 1;

[0056] The second spiral heat conduction channel 202 is fixedly connected to the inner circumference of the graphite tube body 1. The first spiral heat conduction channel 201 and the second spiral heat conduction channel 202 are symmetrically arranged and can be intersected in multiple ways. By forming the first spiral heat conduction channel 201 and the second spiral heat conduction channel 202 on the inner wall of the graphite tube body 1, the heat conduction area can be increased, the heat conduction efficiency can be optimized, and the axial thermal expansion coefficient can be reduced. Thus, the graphite tube can be kept stable under temperature fluctuations during use.

[0057] Reference Figure 4 In a preferred embodiment, the internal heat conduction mechanism 2 further includes:

[0058] Multiple intersection points 204 are located at multiple intersection positions of spiral heat conduction channel one 201 and spiral heat conduction channel two 202;

[0059] Multiple nanocone arrays 203 are fixedly connected to multiple intersections 204. In addition, by setting nanocone arrays 203 at the intersections 204 of spiral heat conduction channel one 201 and spiral heat conduction channel two 202, the turbulent heat transfer area at the intersections 204 is increased, thereby achieving a great optimization of heat conduction efficiency.

[0060] Reference Figure 5 In a preferred embodiment, each support mechanism 3 includes:

[0061] Two support shafts 302 are arranged symmetrically, and each support shaft 302 is provided with a groove 303. An L-shaped bracket 304 is fixedly connected to the outer wall of the opposite side of the two support shafts 302.

[0062] Multiple U-shaped metal pieces 301 are fixedly connected to the outer circumferential walls of two support shafts 302 and movably fit against the inner wall of the T-slot 4.

[0063] Reference Figure 5 In a preferred embodiment, each support mechanism 3 further includes:

[0064] The sleeve 313 is movably sleeved on the outer circumferential wall of the two support shafts 302, and a through hole 312 is provided through one inner wall of the sleeve 313.

[0065] The support rod 306 is movably inserted into the through hole 312, and an arc-shaped support plate 305 is fixedly connected to the outside of the support rod 306.

[0066] Reference Figure 5 In a preferred embodiment, each support mechanism 3 further includes:

[0067] T-shaped bracket 307 is fixedly connected to the inner end of support rod 306, and each end of T-shaped bracket 307 is provided with a slot, and two L-shaped brackets 304 are respectively movably engaged in the slot;

[0068] Two connecting plates 311 are symmetrically fixed to the inner circumference of the sleeve 313. The support mechanism 3 is mainly used to provide longitudinal support when placed in the T-slot 4. Before insertion, the two L-shaped brackets 304 are limited by the T-shaped bracket 307 and compressed by the spring 309. When the support mechanism 3 is inserted into the T-slot 4, as the support mechanism 3 is pushed in, when it touches the bottom, the inner wall of the T-slot 4 pushes the arc-shaped support plate 305, causing the T-shaped bracket 307 to move horizontally, so that the T-shaped bracket 307 is separated from the L-shaped bracket 304. Under the action of the spring 309, the two support shafts 302 can be driven to pop out, increasing the overall length of the support mechanism 3, so that the two ends can abut against the two ends of the T-slot 4. At the same time, the U-shaped metal sheet 301 unfolds and fits against the inner wall of the T-slot 4 to provide support. Based on the setting of the T-slot 4, the surface area is increased, the heat exchange efficiency is improved, and the surface stress concentration can be dispersed to avoid local overload.

[0069] Reference Figure 5 In a preferred embodiment, each support mechanism 3 further includes:

[0070] Two insert rods 310 are respectively fixedly connected to the outer wall of the opposite side of the two connecting plates 311, and are correspondingly inserted into the grooves 303 of the two support shafts 302;

[0071] Two circular support plates 308 are fixedly connected to the opposite ends of two insert rods 310. A spring 309 is fixedly connected between the inner wall of the groove 303 and the circular support plate 308, and the spring 309 surrounds the insert rod 310. The radial preload generated by the elastic compression of the U-shaped metal sheet 301 can offset the tensile stress inside the graphite, thereby reducing the probability of crack initiation. At the same time, the structure, through the setting of the retraction and pop-out structure, can ensure that the two side support shafts 302 only pop outward when the support mechanism 3 reaches the inner installation position, realizing the positioning function and reducing the installation difficulty. At the same time, after the U-shaped metal sheet 301 unfolds in the T-slot 4, it can be just stuck in one side of the inner wall of the T-slot 4, thereby preventing the support mechanism 3 from falling off during use, so that the support mechanism 3 is stably supported in the T-slot 4, avoiding the need for secondary glue fixation, and further reducing the installation difficulty.

[0072] Working principle: By adding nano-carbon fibers, graphene oxide, ceramic particles, and sintering aids to ordinary graphite and resin raw materials, the overall performance of graphite tubes can be greatly improved. Among them, the addition of graphene oxide can increase the tensile strength of carbon fibers by 225% and the Young's modulus by 184%. Its polar functional groups can also improve the bonding force with the matrix such as resin and reduce the brittle defects of graphite tubes. The addition of ceramic particles is based on their excellent thermal conductivity and hardness, and can fill the pores inside the graphite tube to improve the density. After being combined with graphite, it has both thermal conductivity and mechanical stability, thus achieving a simultaneous improvement in the thermal conductivity, density, and mechanical stability of graphite tubes. In addition, the addition of 5wt% boric acid as a sintering aid can greatly reduce the hot pressing temperature and reduce production energy consumption.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing a high thermal conductivity graphite tube, characterized in that, The specific steps include the following: S1: Raw material mixing: Take the raw materials required for the high thermal conductivity graphite tube body and mix them evenly in a certain proportion. The raw materials include nano carbon fiber, graphene oxide, 99.9% high-purity graphite powder, ceramic particles and sintering aids. S2: Tube blank production: The production of graphite tube blanks is achieved by using well-mixed raw materials; S3: Resin impregnation: Prepare the required resin and use a negative pressure environment to impregnate the resin with the tube blank, so that the resin fills the pores of the graphite tube blank. S4: Curing: Place the resin-impregnated graphite tube blank in a curing machine and pre-cur it at 120°C for 11 hours, then raise the temperature to 150°C to complete the cross-linking reaction; S5: High-temperature sintering: Sintering the cured graphite tube in a high-temperature environment; S6: Post-processing: After machining processes such as turning and grinding, and assembly of parts, graphite tubes are produced; S1, the raw material mixing includes the following specific steps: S11: Raw material premixing: Premixing carbon nanofibers with graphene oxide; S12: Raw material ball milling and mixing; 99.9% high-purity graphite powder, nano-carbon fiber mixture and ceramic particles are mixed in the required proportion, and then activated by ball milling to form a composite substrate; S13: Addition of sintering aid: Add 5wt% boric acid as a sintering aid, and mix through a second ball milling process; In S11, the mass ratio of graphene oxide to carbon nanofibers in the raw material premix is ​​0.075wt%:1; In S12, during the ball milling and mixing of raw materials, the diameter of the carbon nanofibers is 50-100 nm, and the mass ratio of 99.9% high-purity graphite powder, carbon nanofibers, and ceramic particles is 6:2:

2.

2. The method for producing a high thermal conductivity graphite tube according to claim 1, characterized in that, The graphite tube in S6 includes: Graphite tube body (1); An internal heat conduction mechanism (2) is provided on the inner circumference of the graphite tube body (1); Multiple T-shaped grooves (4) are equidistantly arranged around the outer periphery of the graphite tube body (1); Multiple support mechanisms (3) are installed in multiple T-slots (4).

3. The method for producing a high thermal conductivity graphite tube according to claim 2, characterized in that, The internal heat conduction mechanism (2) includes: Spiral heat conduction channel 1 (201) is fixedly connected to the inner circumference of the graphite tube body (1); Spiral heat conduction channel 2 (202) is fixedly connected to the inner circumference of the graphite tube body (1). Spiral heat conduction channel 1 (201) and spiral heat conduction channel 2 (202) are symmetrically arranged and can be intersected in multiple ways.

4. The method for producing a high thermal conductivity graphite tube according to claim 3, characterized in that, The internal heat conduction mechanism (2) further includes: Multiple intersections (204) are located at multiple intersections of the first spiral heat conduction channel (201) and the second spiral heat conduction channel (202); Multiple nanocone arrays (203) are fixedly connected to multiple intersections (204).

5. The method for producing a high thermal conductivity graphite tube according to claim 2, characterized in that, Each of the aforementioned support mechanisms (3) includes: Two support shafts (302) are arranged symmetrically, and each support shaft (302) is provided with a groove (303). L-shaped brackets (304) are fixedly connected to the outer walls of opposite sides of the two support shafts (302). Multiple U-shaped metal pieces (301) are fixedly connected to the outer circumferential walls of two support shafts (302) and movably fit against the inner wall of the T-slot (4).

6. The method for producing a high thermal conductivity graphite tube according to claim 5, characterized in that, Each of the support mechanisms (3) further includes: The sleeve (313) is movably sleeved on the outer circumferential wall of the two support shafts (302), and a through hole (312) is provided on one side of the inner wall of the sleeve (313). The support rod (306) is movably inserted into the through hole (312), and an arc-shaped support plate (305) is fixedly connected to the outside of the support rod (306).

7. The method for producing a high thermal conductivity graphite tube according to claim 6, characterized in that, Each of the support mechanisms (3) further includes: T-shaped bracket (307) is fixedly connected to the inner end of the support rod (306), and the two ends of the T-shaped bracket (307) are respectively provided with slots, and the two L-shaped brackets (304) are respectively movably engaged in the slots; Two connecting plates (311) are symmetrically fixed to the inner circumference of the sleeve (313).

8. The method for producing a high thermal conductivity graphite tube according to claim 7, characterized in that, Each of the support mechanisms (3) further includes: Two insert rods (310) are fixedly connected to the outer walls of the opposite sides of the two connecting plates (311) respectively, and are inserted into the grooves (303) of the two support shafts (302); Two circular support plates (308) are fixedly connected to the opposite ends of two insert rods (310), and a spring (309) is fixedly connected between the inner wall of the groove (303) and the circular support plate (308), and the spring (309) surrounds the insert rod (310).

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