A carbon / carbon composite material and a method for manufacturing the same, and a carbon / carbon PECVD support frame

Abstract

The present application relates to the technical field of composite materials, and provides a carbon / carbon composite material and a preparation method thereof, and a carbon / carbon PECVD bearing frame.The present application mixes liquid resin and carbon material powder to obtain a carbon-containing resin liquid; carbon cloth is dipped in the carbon-containing resin liquid to obtain a prepreg; the prepreg is laminated and then subjected to mold pressing treatment; the obtained plate blank is carbonized; the carbonized plate material is then dipped in pitch; the dipped carbonized plate material is carbonized again to obtain a carbon / carbon plate material; and the carbon / carbon plate material is subjected to graphitization treatment to obtain a carbon / carbon composite material.The carbon / carbon composite material is subjected to fine machining to obtain the carbon / carbon PECVD bearing frame.The carbon / carbon PECVD bearing frame provided by the present application has the advantages of low density, high strength, and designable size, can adapt to the complex process environment of PECVD, is not prone to damage, has excellent mechanical properties, has a low replacement frequency, has a long service life, and can effectively reduce the cost of the PECVD process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, and in particular to a carbon / carbon composite material and a preparation method thereof, and a carbon / carbon PECVD bearing frame. BACKGROUND

[0002] With the increasingly strong development momentum of new energy, the photovoltaic solar power generation industry is listed as a key development project in many countries, and solar cell module systems have also received more and more attention. In the production process of single crystal / multicrystalline silicon cells, film plating on a silicon wafer is an important process, which can reduce light reflection and improve light utilization. The silicon nitride film process currently used more is plasma enhanced chemical vapor deposition (PECVD) process. This process uses microwaves or radio frequency to form a plasma containing thin film component atoms in a local area, and the plasma has strong chemical activity and can easily react to deposit the desired thin film on the substrate.

[0003] The PECVD boat is a carrier for silicon wafers during film plating production. Due to the complex process environment of PECVD, the PECVD boat or boat plate currently used is mainly made of graphite. Graphite products have low impurity content, high purity and corrosion resistance, high thermal conductivity, moderate electrical conductivity, and stable physical and chemical properties, but in actual application, the mechanical properties of graphite are poor, which leads to easy damage of the graphite boat during film plating and cleaning, and short service life. The traditional graphite bearing frame (boat) is machined on a whole graphite plate and supplemented with related accessories. Therefore, researchers mainly optimize the details of the graphite bearing frame structure in order to improve the bearing capacity and improve the PECVD production efficiency. For example, the utility model patent with the application number CN201720071874.5 provides a graphite frame for a plate type PECVD. The graphite grid is changed from the original 5x10 to 5x11, which increases the bearing capacity of the graphite frame by 10%, increases the production efficiency by 10%, reduces energy consumption and material consumption, and reduces production cost. The utility model patent with the application number CN201320758895.6 provides a graphite frame, which is provided with a carbon fiber reinforcing plate at the upper and lower two side edges of the graphite frame. The carbon fiber reinforcing plate, which is located in the same plane as the graphite frame body, not only plays a supporting role, but also avoids the influence of the existing graphite fixed plate on the uniformity of the film plating gas flow, thereby preventing the red and white phenomenon caused by the influence of the existing graphite fixed plate on the uniformity of the film plating gas flow, and ensuring the quality of the battery piece film plating. However, the above-mentioned technologies solve some problems, but do not solve the problem of low strength and easy damage of the graphite bearing frame from the root cause.

[0004] In summary, the existing graphite bearing frame is mainly made of graphite plate machined with corresponding accessories. Limited by the structure design of the bearing frame and the material performance of the graphite material itself, the graphite bearing frame has limited space for improvement in the loading capacity of silicon wafers. In addition, the graphite bearing frame is easily damaged in harsh film plating environment and pickling process, greatly increasing the replacement frequency of the graphite bearing frame and the cost of PECVD process. SUMMARY

[0005] Therefore, the present application provides a carbon / carbon composite material and a preparation method thereof, and a carbon / carbon PECVD bearing frame. The carbon / carbon composite material provided by the present application has high strength, and the carbon / carbon PECVD bearing frame prepared therefrom can adapt to the complex process environment of PECVD, is not easily damaged, has excellent mechanical properties, low replacement frequency, long service life, and can effectively reduce the cost of PECVD process.

[0006] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0007] A preparation method of a carbon / carbon composite material, comprising the following steps:

[0008] Mixing a liquid resin and a carbon material powder to obtain a carbon-containing resin liquid;

[0009] First impregnating the carbon cloth in the carbon-containing resin liquid to obtain a prepreg;

[0010] Laying the prepreg and then performing a mold pressing treatment to obtain a plate blank;

[0011] First carbonizing the plate blank to obtain a carbonized plate material;

[0012] Second impregnating the carbonized plate material in pitch, and second carbonizing the carbonized plate material after the second impregnation to obtain a carbon / carbon plate material;

[0013] Graphitizing the carbon / carbon plate material to obtain a carbon / carbon composite material.

[0014] Preferably, the liquid resin is one or more of phenolic resin, furan resin and benzoxazine resin; the carbon material powder is carbon powder and / or graphite powder; and the mass ratio of the liquid resin to the carbon material powder is 100:(5-10);

[0015] The carbon cloth has a grammage of 300-400 g / m 2 ; and the prepreg has a glue content of 30-45 wt%;

[0016] The number of layers of the lay-up is 14-20 layers.

[0017] Preferably, the schedule of the molding treatment is set according to the DSC curve of the liquid resin, specifically, the temperature of the molding treatment is determined according to the DSC curve of the liquid resin, the temperature of the molding treatment is lower than the temperature corresponding to the exothermic peak of the DSC curve, and higher than the temperature at the beginning of the DSC curve; the liquid resin samples in multiple groups are cured at the temperature of the molding treatment, and the curing time of each group of liquid resin samples is successively prolonged, and the optimal curing time, i.e. the time of the molding treatment, is determined according to the T g values of the cured products of each group of liquid resin.

[0018] Preferably, the molding treatment comprises eleven stages, which are successively referred to as the first stage to the eleventh stage; the first stage is a temperature rising stage, the temperature rising time is 69-71 min, the temperature at the end of the temperature rising is 96-114℃, and the pressure is 0 MPa; the second stage is a temperature holding stage, the temperature holding time is 29-31 min, the temperature holding temperature is 96-114℃, and the pressure is 0 MPa; the third stage is a temperature holding stage, the temperature holding time is 1-3 min, the temperature holding temperature is 96-114℃, and the pressure is 0.05-0.15 MPa; the fourth stage is a temperature holding stage, the temperature holding time is 1-3 min, the temperature holding temperature is 96-114℃, and the pressure is 0.25-0.35 MPa; the fifth stage is a temperature holding stage, the temperature holding time is 1-3 min, the temperature holding temperature is 96-114℃, and the pressure is 0.45-0.55 MPa; the sixth stage is a temperature holding stage, the temperature holding time is 1-3 min, the temperature holding temperature is 96-114℃, and the pressure is 0.75-0.85 MPa; the seventh stage is a temperature holding stage, the temperature holding time is 2-4 min, the temperature holding temperature is 96-114℃, and the pressure is 0.75-1.3 MPa; the eighth stage is a temperature rising stage, the temperature rising time is 49-51 min, the end temperature is 146-154℃, and the pressure is 0.75-1.3 MPa; the ninth stage is a temperature holding stage, the temperature holding time is 29-31 min, the temperature holding temperature is 146-154℃, and the pressure is 0.75-1.3 MPa; the tenth stage is a temperature rising stage, the temperature rising time is 59-61 min, the end temperature is 176-184℃, and the pressure is 0.75-1.3 MPa; the eleventh stage is a temperature holding stage, the temperature holding time is 84-86 min, the temperature holding temperature is 176-184℃, and the pressure is 0.75-1.3 MPa.

[0019] Preferably, the temperature of the first carbonization is 850-1100℃, the temperature holding time is 1-3 h, and the temperature rising rate to the temperature of the first carbonization is 10-100℃ / h; after the temperature holding is completed, the temperature is decreased to room temperature at a rate of 50-100℃ / h.

[0020] The temperature of the second impregnation is 160-280 DEG C, the pressure is 2-4 MPa, and the time is 2-4 hours, and after the impregnation is completed, the pitch is solidified by cooling.

[0021] Preferably, the second carbonization comprises six stages in sequence, namely, a first stage to a sixth stage; the first stage is a temperature rising stage, starting from room temperature, and the terminal temperature of the temperature rising is 196-204 DEG C, and the time of the temperature rising is 3 hours ± 10 minutes; the second stage is a temperature holding stage, the temperature of the temperature holding is 196-204 DEG C, and the time of the temperature holding is 2 hours ± 10 minutes; the third stage is a temperature rising stage, the temperature rises from the temperature of the second stage to 596-604 DEG C, and the time of the temperature rising is 15 hours ± 10 minutes; the fourth stage is a temperature holding stage, the temperature of the temperature holding is 596-604 DEG C, and the time of the temperature holding is 2 hours ± 10 minutes; the fifth stage is a temperature rising stage, the temperature rises from the temperature of the fourth stage to 796-804 DEG C, and the time of the temperature rising is 4 hours ± 10 minutes; and the sixth stage is a temperature holding stage, the temperature of the temperature holding is 796-804 DEG C, and the time of the temperature holding is 2 hours ± 10 minutes.

[0022] Preferably, the density of the carbon / carbon plate is 1.5 g / cm 3 above; if the density of the plate obtained after the second carbonization is lower than 1.5 g / cm 3 , the process of the second impregnation and the second carbonization is repeated until the density of the carbon / carbon plate is 1.5 g / cm 3 above;

[0023] The temperature of the graphitization treatment is 1800-2300 DEG C, and the time is 2-6 hours.

[0024] The application further provides a carbon / carbon composite material prepared by the preparation method in the above scheme.

[0025] The application further provides a carbon / carbon PECVD bearing frame prepared from the carbon / carbon composite material in the above scheme.

[0026] The application further provides a preparation method of the carbon / carbon PECVD bearing frame in the above scheme, comprising the following steps: finely machining the carbon / carbon composite material in the above scheme to obtain the carbon / carbon PECVD bearing frame.

[0027] This invention provides a method for preparing carbon / carbon composite materials, comprising the following steps: mixing liquid resin and carbon material powder to obtain a carbon-containing resin liquid; first impregnating carbon cloth in the carbon-containing resin liquid to obtain a prepreg; laying the prepreg and then molding it to obtain a blank; first carbonizing the blank to obtain a carbonized sheet; second impregnating the carbonized sheet in asphalt, and second carbonizing the second-impregnated carbonized sheet to obtain a carbon / carbon sheet; and graphitizing the carbon / carbon sheet to obtain a carbon / carbon composite material. This invention adds carbon material powder to the liquid resin, which can fill the voids caused by resin decomposition during the subsequent carbonization process of the sheet, ensuring the adhesion between carbon fibers and resin, preventing delamination between carbon cloths, and thus improving the strength of the final carbon / carbon composite material. Furthermore, compared to other similar mesh-reinforced or Z-axis reinforced sheets, this invention significantly improves the strength of the sheet by adding carbon material powder, offering clear cost and efficiency advantages. The entire process of this invention combines efficiency and production capacity advantages, with a very short production cycle compared to other molding methods, maximizing production capacity.

[0028] Furthermore, the present invention controls the cooling rate during the first carbonization process, so that the stress generated during carbonization can be released slowly, reducing the impact of stress on the interlayer, thereby ensuring the mechanical properties of the final carbon / carbon composite material.

[0029] This invention also provides a carbon / carbon PECVD support frame, prepared from the carbon / carbon composite material described in the above-described scheme. Compared with traditional graphite support frames, the carbon / carbon PECVD support frame provided by this invention has advantages such as low density, high strength, and customizable dimensions. It can adapt to the complex process environment of PECVD, is not easily damaged, has excellent mechanical properties, low replacement frequency, and long service life, effectively reducing the cost of the PECVD process. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the carbon / carbon PECVD support frame of the present invention. Detailed Implementation

[0031] This invention provides a method for preparing carbon / carbon composite materials, comprising the following steps:

[0032] Liquid resin and carbon material powder are mixed to obtain a carbon-containing resin liquid;

[0033] The carbon cloth is first impregnated in the carbon-containing resin liquid to obtain a prepreg.

[0034] The prepreg is laid up and then molded to obtain a slab.

[0035] The slab is subjected to a first carbonization process to obtain a carbonized sheet.

[0036] carburizing the carbonized plate in pitch to obtain a second impregnated carbonized plate, and second carbonizing the second impregnated carbonized plate to obtain a carbon / carbon plate;

[0037] graphitizing the carbon / carbon plate to obtain a carbon / carbon composite material.

[0038] The liquid resin is preferably one or more of phenolic resin, furan resin and benzoxazine resin; in specific embodiments of the present application, the phenolic resin is preferably Y6412 of Guangming Resin Factory, PR55738 of Sumitomo or EXP-0026E of Yushi of Leling, Shandong; the furan resin is preferably HW154; the benzoxazine resin is preferably Han Gao Letai BZ9110 AERO; the carbon material powder is preferably carbon powder and / or graphite powder, the grade of the carbon powder is preferably 501P or T-5P; the particle size of the carbon material powder is preferably 20 μm or less; the mass ratio of the liquid resin and the carbon material powder is preferably 100:(5-10), more preferably 100:(6-8); the mixing method is preferably mechanical mixing or ultrasonic mixing; the viscosity of the carbon-containing resin liquid at 25°C is preferably 2000-8000 mPa·s, more preferably 3000-6000 mPa·s.

[0039] After obtaining the carbon-containing resin liquid, the carbon cloth is first impregnated in the carbon-containing resin liquid to obtain a prepreg. In the present application, the gram weight of the carbon cloth is preferably 300-400 g / m 2 , more preferably 330-360 g / m 2 ; the carbon cloth is preferably plain weave carbon cloth or twill cloth; the specification of the carbon wire in the carbon cloth is preferably 3K, 6K, 12K, 24K or 48K; the glue content of the prepreg is preferably 30-45 wt%, more preferably 35-40 wt%; after the first impregnation, preferably further including scraping glue, drying, refrigeration and winding to obtain a prepreg; in specific embodiments of the present application, a resin impregnation equipment is preferably used to prepare the prepreg; the resin impregnation equipment preferably includes a feeding device, an impregnation device, a scraping glue device, a drying device, a refrigeration device and a winding device; the present application does not have special requirements for the specific operation method of the first impregnation, scraping glue, drying, refrigeration and winding, and the method known to those skilled in the art can be used. In specific embodiments of the present application, the prepared prepreg should be pressed into a plate within 1 month, if not used for a short period of time (such as 10 days), the prepreg needs to be stored in a sealed environment at minus 18°C, and the shelf life is half a year.

[0040] After obtaining the prepreg, the present invention lays up the prepreg and then performs molding to obtain a blank. In this invention, before laying up, the prepreg is preferably cut, preferably using a CNC automatic fabric cutting machine with an efficiency preferably of 1700 mm / s. The cut size and quantity match the design requirements, leaving a certain allowance for subsequent CNC machining. The dimensional error of the cut fabric is ±1 mm.

[0041] In this invention, the number of layers is determined according to the required thickness. In a specific embodiment of the invention, the number of layers is preferably 14 to 20, and the thickness of the carbon / carbon composite material is preferably 5 to 7 mm. In a specific embodiment of the invention, a steel plate is preferably used as the supporting mold. The steel plate is required to be flat and coated with a release agent. The cut prepreg is evenly and evenly laid on the steel plate. Each layer is smoothed with a plastic scraper to prevent wrinkles from forming on the surface. Then, the layers are laid one by one according to the required thickness. After all the layers are laid, another steel plate coated with a release agent is placed on top.

[0042] In this invention, during the molding process, different molding processes are preferably selected based on the characteristics of the resin used. The molding process is preferably set according to the DSC curve of the liquid resin, specifically: the molding temperature is determined based on the DSC curve of the liquid resin, and the molding temperature is lower than the temperature corresponding to the exothermic peak of the DSC curve but higher than the temperature at the beginning of the DSC curve; multiple groups of liquid resin samples are cured at the molding temperature, with the curing time of each group of liquid resin samples progressively extended, based on the Tc of each group of cured liquid resin samples. g The optimal curing time is determined by the value, which is the molding time. In this invention, when curing multiple resin samples, there is no particular requirement for the number of resin samples; it can be determined according to actual needs. In a specific embodiment of this invention, the longer the curing time, the higher the T value of the resulting cured product. g The higher the value, the more the T of the solidified material... g When the value no longer changes with the extension of curing time, it is considered to be fully cured, and the time when it is fully cured is the optimal curing time.

[0043] In the specific embodiment of the present application, the mould pressing process preferably comprises eleven stages, sequentially denoted as first stage to eleventh stage; the first stage is a temperature rising stage, the temperature rising time is 69-71 min, preferably 70 min, the temperature at the end point of temperature rising is 96-114℃, preferably 100-110℃, and the pressure is 0 MPa; the second stage is a temperature holding stage, the temperature holding time is 29-31 min, preferably 30 min, the temperature holding temperature is 96-114℃, preferably 100-110℃, and the pressure is 0 MPa; the third stage is a temperature holding stage, the temperature holding time is 1-3 min, preferably 2 min, the temperature holding temperature is 96-114℃, preferably 100-110℃, and the pressure is 0.05-0.15 MPa, preferably 0.1 MPa; the fourth stage is a temperature holding stage, the temperature holding time is 1-3 min, preferably 2 min, the temperature holding temperature is 96-114℃, preferably 100-110℃, and the pressure is 0.25-0.35 MPa, preferably 0.3 MPa; the fifth stage is a temperature holding stage, the temperature holding time is 1-3 min, preferably 2 min, the temperature holding temperature is 96-114℃, preferably 100-110℃, and the pressure is 0.45-0.55 MPa, preferably 0.5 MPa; the sixth stage is a temperature holding stage, the temperature holding time is 1-3 min, preferably 2 min, the temperature holding temperature is 96-114℃, preferably 100-110℃, and the pressure is 0.75-0.85 MPa, preferably 0.8 MPa; the seventh stage is a temperature holding stage, the temperature holding time is 2-4 min, preferably 3 min, the temperature holding temperature is 96-114℃, preferably 100-110℃, and the pressure is 0.75-1.3 MPa, preferably 0.8-1.25 MPa; the eighth stage is a temperature rising stage, the temperature rising time is 49-51 min, preferably 50 min, the end point temperature is 146-154℃, preferably 150℃, and the pressure is 0.75-1.3 MPa, preferably 0.8-1.25 MPa; the ninth stage is a temperature holding stage, the temperature holding time is 29-31 min, preferably 30 min, the temperature holding temperature is 146-154℃, preferably 150℃, and the pressure is 0.75-1.3 MPa, preferably 0.8-1.25 MPa; the tenth stage is a temperature rising stage, the temperature rising time is 59-61 min, preferably 60 min, the end point temperature is 176-184℃, preferably 180℃, and the pressure is 0.75-1.3 MPa, preferably 0.8-1.25 MPa; and the eleventh stage is a temperature holding stage, the temperature holding time is 84-86 min, preferably 85 min, the temperature holding temperature is 176-184℃, preferably 180℃, and the pressure is 0.75-1.3 MPa, preferably 0.8-1.25 MPa.

[0044] After the slab is obtained, the slab is subjected to first carbonization to obtain a carbonized slab. In the present application, the first carbonization is preferably performed in a carbonization furnace. In order to reduce deformation and delamination of the slab during carbonization, the slab is placed between two graphite plate fixtures. The carbonization process needs to match the thermal weight loss curve of the resin. The heating rate of each stage is determined according to the slope change of the thermal weight loss curve. For the region with a relatively fast slope change, the cooling rate needs to be appropriately prolonged. Specifically, in the present application, the temperature of the first carbonization is preferably 850-1100℃, more preferably 900-1080℃, the holding time is preferably 1-3h, more preferably 1.5-2.5h, and the heating rate for heating to the temperature of the first carbonization is preferably 10-100℃ / h, more preferably 20-80℃ / h. After the holding is completed, the temperature is preferably reduced to room temperature at a rate of 50-100℃ / h, more preferably 60-80℃ / h. In specific embodiments of the present application, power cooling is preferably used to maintain the above-mentioned cooling rate. In the first carbonization process of the present application, the cooling rate is controlled, so that the stress generated during carbonization can be slowly released, the influence of the stress on the interlayer is reduced, and the mechanical properties of the finally obtained carbon / carbon composite material are ensured

[0045] The carbonized slab is subjected to second impregnation in pitch, and the carbonized slab after the second impregnation is subjected to second carbonization to obtain a carbon / carbon slab. In the present application, the softening point of the pitch is preferably 175-185℃, the carbon residue value is preferably greater than 54wt%, the coking value is preferably greater than 57wt%, the quinoline insoluble content is preferably less than 0.5%, and the ash content is preferably less than 0.1wt%. In specific embodiments of the present application, the type of the pitch is preferably PE-180.

[0046] In the present application, the temperature of the second impregnation is preferably 160-280℃, more preferably 160-210℃ or 200-280℃. In specific embodiments of the present application, the temperature of the second impregnation is preferably controlled to a viscosity of the pitch of 200-400mPa·s. The pressure of the second impregnation is preferably 2-4MPa, more preferably 2.5-3.5MPa, and the time is preferably 2-4h, more preferably 2.5-3.5h. After the impregnation is completed, the temperature is reduced to solidify the pitch. In specific embodiments of the present application, the carbonized slab is preferably placed in a vacuum pressure impregnation furnace, the vacuum pressure impregnation furnace is heated to 161-210℃, the pitch is sucked into the vacuum pressure impregnation furnace by using the pressure difference, and then the pressure is increased to 2-4MPa. After the pressure is maintained for 2-4h, the excess pitch is returned, and then the temperature is reduced to solidify the pitch impregnated in the carbonized slab.

[0047] In the present application, the second carbonization is preferably matched with the thermal gravimetric curve (i.e. DSC curve) of the pitch. Specifically, the second carbonization preferably comprises six stages in sequence, which are referred to as the first stage to the sixth stage; the first stage is a temperature rising stage, starting from room temperature, the terminal temperature of the temperature rising is 196-204℃, preferably 200℃, and the time of the temperature rising is 3h±10min; the second stage is a temperature holding stage, the temperature of the temperature holding is 196-204℃, preferably 200℃, and the time of the temperature holding is 2h±10min; the third stage is a temperature rising stage, starting from the temperature of the second stage, the temperature rising is to 596-604℃, preferably 600℃, and the time of the temperature rising is 15h±10min; the fourth stage is a temperature holding stage, the temperature of the temperature holding is 596-604℃, preferably 600℃, and the time of the temperature holding is 2h±10min; the fifth stage is a temperature rising stage, starting from the temperature of the fourth stage, the temperature rising is to 796-804℃, preferably 800℃, and the time of the temperature rising is 4h±10min; the sixth stage is a temperature holding stage, the temperature of the temperature holding is 796-804℃, preferably 800℃, and the time of the temperature holding is 2h±10min.

[0048] In the present application, the second carbonization is preferably carried out in a carbonization furnace, and the pressure in the furnace is preferably slightly positive (about tens of Pa); the second carbonization is preferably carried out under the protection of nitrogen.

[0049] After the above-mentioned second carbonization is completed, the nitrogen valve is preferably closed, and the cooling is started; when the furnace temperature is reduced to 200℃, the cover is opened, and the carbon / carbon plate is taken out; the cooling process of the second carbonization does not need to be powered.

[0050] In the present application, the density of the carbon / carbon plate is preferably 1.5g / cm 3 or more; if the density of the plate obtained after the second carbonization is less than 1.5g / cm 3 , the process of the second impregnation and the second carbonization is preferably repeated until the density of the obtained carbon / carbon plate is 1.5g / cm 3 or more.

[0051] After the carbon / carbon plate is obtained, the carbon / carbon plate is preferably subjected to graphitization treatment to obtain a carbon / carbon composite material. In the present application, the temperature of the graphitization treatment is preferably 1800-2300℃, more preferably 1900-2100℃, and the time of the graphitization treatment is preferably 2-6h, more preferably 3-5h; in the specific embodiments of the present application, the carbon / carbon plate is preferably provided with a graphite tooling before the graphitization treatment; the present application improves the graphitization degree of the plate and reduces the internal ash content through the graphitization treatment.

[0052] The present application also provides a carbon / carbon composite material prepared by the preparation method described in the above-mentioned scheme.

[0053] The present application also provides a carbon / carbon PECVD bearing frame prepared from the carbon / carbon composite material described in the above solution. In the present application, the size of the carbon / carbon PECVD bearing frame is preferably 2500mmx1500mm, and the thickness is preferably 1-20mm; Figure 1 Figure 1 is a schematic view of the carbon / carbon PECVD bearing frame of the present application.

[0054] The present application also provides a preparation method of the carbon / carbon PECVD bearing frame described in the above solution, comprising the following steps: finely machining the carbon / carbon composite material described in the above solution to obtain the carbon / carbon PECVD bearing frame; the step of finely machining comprises polishing, edge cutting and milling.

[0055] The carbon / carbon PECVD bearing frame provided by the present application has the advantages of low density, high strength, and size design, etc. compared with ordinary graphite bearing frames, can adapt to the complex process environment of PECVD, is not easy to be damaged, has low replacement frequency, long service life, and can effectively reduce the cost of PECVD process. Table 1 is a comparison result of the carbon / carbon PECVD bearing frame of the present application and ordinary graphite bearing frames.

[0056] Table 1 Comparison result of the PECVD bearing frame of the present application and ordinary graphite bearing frames

[0057]

[0058]

[0059] The technical solutions in the present application will be described clearly and completely below in combination with the embodiments in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0060] Example 1

[0061] (1) Mix liquid phenolic resin (Y6412 from Guangming Resin Factory) with carbon powder (brand 501P), the mass ratio of phenolic resin to carbon black is 100:5, and use mechanical mixing. The viscosity of the obtained carbon-containing resin liquid after mixing is 4000mPa·s at 25℃.

[0062] (2) Use the carbon-containing resin liquid prepared in step (1) to impregnate carbon cloth, and use resin impregnation equipment (including discharging device, impregnation device, glue scraping device, drying device, refrigeration device, and winding device) to impregnate the selected carbon cloth (carbon cloth grammage 420g / m 2Plain weave, wherein the carbon filaments are selected from 12k) to make a prepreg, the finished prepreg content of 36% ~ 38% glue.

[0063] (3) according to the design requirements of the size 2100mm x 1100mm, using numerical control automatic cutting machine for cutting, the number of 15 pieces. The cutting of the prepreg cloth in the steel plate for laying operation, steel flat plate requirements flat, surface coating release agent. The carbon cloth is evenly laid on the steel plate, each layer requires the use of plastic scraper to scrape, prevent the surface from folding, then according to the thickness of 5.5mm for each layer of laying. After all the laying is completed, the upper surface is covered with another steel plate coated with release agent.

[0064] (4) the prepreg after the laying is pressed to get the plate blank; the pressing process is shown in table 2;

[0065] Table 2 pressing process conditions

[0066]

[0067] (5) the plate blank obtained in step (4) is placed into two graphite plate tooling, and then placed in the carbonization furnace for carbonization, with a rate of 50 ℃ / h to 850 ℃, and kept for 2 h, and then cooled with power, keeping the cooling rate at 60 ℃ / h; the carbonized plate is obtained.

[0068] (6) the carbonized plate is placed into a vacuum pressure impregnation furnace, and the pitch with the brand PE180 is used to impregnate the carbonized plate, the vacuum impregnation furnace is heated to 200 ℃, the viscosity of the pitch is reduced to 400 mPa.s, the impregnation liquid is completely absorbed into the furnace with the flat plate by using the vacuum pressure difference, and then the pressure is pressed to 3 MPa, and the pressure is kept for 3 h, and then the excess impregnation liquid is returned, and the furnace is cooled to harden the pitch.

[0069] Then the plate is taken out and placed in the carbonization furnace for carbonization, and the carbonization process needs to match the thermal weight loss curve of the pitch; the specific carbonization process is shown in table 3.

[0070] Table 3 carbonization process conditions

[0071]

[0072] After the sixth stage of keeping warm, the nitrogen valve is closed to start cooling, and when the furnace temperature drops to 200 ℃, the cover is opened, and the carbon / carbon plate is taken out, and the carbonization process does not need to be cooled with power at this time.

[0073] After carbonization, the density of the plate is measured, and the density is 1.32 g / cm 3 , which does not reach 1.5 g / cm 3 above.

[0074] After repeating step (6) once, the density was determined by the drainage method to be 1.41 g / cm 3 After repeating step (6) twice, the density was determined by the drainage method to be 1.52 g / cm 3 , which met the requirements, and a carbon / carbon plate was obtained.

[0075] (7) The carbon / carbon plate was subjected to high-temperature graphitization treatment with a graphite tool, the treatment temperature was 1850°C, and the time was 3 h. After the treatment, the density was determined by the drainage method to be 1.59 g / cm 3 .

[0076] (8) The carbon / carbon plate after the graphitization treatment was finely machined according to the final structure design of the bearing frame, and the main machining steps included grinding, edge cutting, and milling.

[0077] Example 2

[0078] (1) Liquid phenolic resin (EXP-0026E of Yushi, Leling, Shandong) was mixed with carbon powder (T-5P), the mass ratio of the phenolic resin and the carbon black was 100:8, mechanical mixing was adopted, and the viscosity of the obtained carbon-containing resin liquid after the mixing was 5000 mPa·s at 30°C.

[0079] (2) The carbon cloth was impregnated with the carbon-containing resin liquid prepared in step (1), and the selected carbon cloth (carbon cloth grammage 320 g / m 2 plain weave, in which the carbon wire was selected to be 24k) was made into a prepreg by using a resin impregnation equipment (including a feeding device, an impregnation device, a glue scraping device, a drying device, a refrigeration device, and a winding device). The glue content of the prepared prepreg was 36% to 38%.

[0080] (3) The prepreg was cut by using a numerical control automatic cloth cutting machine according to the designed size of 2060 mm×1060 mm, and the number was 12 pieces. The cut prepreg cloth was laid on a steel flat plate, the steel flat plate was required to be flat, and the surface was brushed with a release agent. The carbon cloth was evenly and flatly laid on the steel flat plate, a plastic scraper was used to scrape each layer to prevent wrinkles on the surface, and then the prepreg was laid layer by layer according to the thickness of 4 mm. After the whole laying was completed, the upper surface was covered with another steel flat plate coated with a release agent.

[0081] (4) The laid prepreg was subjected to molding to obtain a plate blank; the molding process is shown in Table 4.

[0082] Table 4 Molding process conditions

[0083]

[0084]

[0085] (5) Put the slab obtained in step (4) into two graphite plate fixtures, and then place it in a carbonization furnace to perform carbonization, and heat it to 900°C at a rate of 60°C / h, and keep it for 2h, and then perform power reduction, and keep the reduction rate at 55°C / h; and obtain a carbonized plate.

[0086] (6) Put the carbonized plate into a vacuum pressure impregnation furnace, and perform impregnation of the carbonized plate with pitch of PE250, heat the vacuum impregnation furnace to 255, and reduce the viscosity of the pitch to 400 mPa.s, and use the vacuum pressure difference to suck all the impregnation liquid into the furnace containing the plate, and then pressurize to 4 MPa, keep the pressure for 4h, and then return the excess impregnation liquid, and cool the furnace to harden the pitch.

[0087] Then take out the plate and place it in a carbonization furnace to perform carbonization, and at this time the carbonization process needs to match the thermal gravimetric curve of the pitch; the specific carbonization process is shown in Table 5.

[0088] Table 5 Carbonization process conditions

[0089]

[0090] After the completion of the sixth stage of heat preservation, close the nitrogen valve to start cooling, and when the furnace temperature drops to 200°C, open the cover, and take out the carbon / carbon plate, and at this time the carbonization process does not need to be cooled with power.

[0091] After the completion of carbonization, the density of the plate is measured, and the density is 1.22 g / cm 3 , which does not reach 1.5 g / cm 3 .

[0092] After repeating step (6) once, the density is measured by the drainage method to be 1.31 g / cm 3 , after repeating step (6) twice, the density is measured by the drainage method to be 1.41 g / cm 3 , after repeating step (6) twice, the density is measured by the drainage method to be 1.5 g / cm 3 , which meets the requirements, and the carbon / carbon plate is obtained.

[0093] (7) Put the carbon / carbon plate on the graphite fixture to perform high-temperature graphitization treatment, and the treatment temperature is 1950°C, and the time is 4h. After the treatment is completed, the density is measured by the drainage method to be 1.57 g / cm 3 .

[0094] (8) According to the final structure design of the bearing frame, the carbon / carbon plate after graphitization treatment is finely machined, and the main machining steps include polishing, edge cutting, and milling.

[0095] The density uniformity, tensile strength, bending strength, bending modulus, thermal expansion coefficient, thermal conductivity and resistivity of the carbon / carbon support frame prepared in Examples 1-2 were tested, and the testing method and testing results are shown in Table 6.

[0096] Table 6 Testing results of the properties of the carbon / carbon support frame prepared in Examples 1-2

[0097]

[0098] According to the data in Table 6, it can be seen that the carbon / carbon support frame provided by the present application has small density and high strength, and the thermal expansion coefficient, thermal conductivity and resistivity are equivalent to those of the graphite support frame, and has excellent performance. When it is applied to the PECVD process, it can adapt to the complex process environment of PECVD and is not easily damaged, has low replacement frequency, long service period (the service time of conventional graphite support frame is 3-6 months, and the service time of the carbon / carbon support frame of the present application can reach about 12 months), and can effectively reduce the cost of PECVD process.

[0099] The above only describes the preferred embodiments of the present application, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A method for preparing a carbon / carbon composite material, characterized in that, Includes the following steps: A liquid resin and carbon material powder are mixed to obtain a carbon-containing resin liquid; the liquid resin is one or more of phenolic resin, furan resin and benzoxazine resin. The carbon cloth is first impregnated in the carbon-containing resin solution to obtain a prepreg. The prepreg is laid up and then molded to obtain a slab. The slab is subjected to a first carbonization process to obtain a carbonized sheet. The carbonized board is second-impregnated in asphalt, and the second-impregnated carbonized board is second-carbonized to obtain a carbon / carbon board. The carbon / carbon sheet is graphitized to obtain a carbon / carbon composite material. The temperature of the first carbonization is 850~1100℃, the holding time is 1~3h, and the heating rate to the temperature of the first carbonization is 10~100℃ / h; after the holding time is completed, the temperature is reduced to room temperature at a rate of 50~100℃ / h. The second carbonization process comprises six sequential stages, denoted as Stage 1 to Stage 6. Stage 1 is a heating stage, starting from room temperature and increasing to a final temperature of 196-204℃ over a period of 3 hours ± 10 minutes. Stage 2 is a holding stage, maintaining a temperature of 196-204℃ for 2 hours ± 10 minutes. Stage 3 is a heating stage, increasing the temperature from Stage 2 to 596-604℃ over a period of 15 hours ± 10 minutes. Stage 4 is a holding stage, maintaining a temperature of 596-604℃ for 2 hours ± 10 minutes. Stage 5 is a heating stage, increasing the temperature from Stage 4 to 796-804℃ for 4 hours ± 10 minutes. Stage 6 is a holding stage, maintaining a temperature of 796-804℃ for 2 hours ± 10 minutes. The graphitization treatment is carried out at a temperature of 1800~1950℃ for 2~6 hours; the density of the carbon / carbon composite material is greater than 1.55 g / cm³. 3 Less than or equal to 1.59 g / cm³ 3 The tensile strength of the carbon / carbon composite material is greater than 180 MPa.

2. The preparation method according to claim 1, characterized in that, The carbon material powder is carbon powder and / or graphite powder; the mass ratio of the liquid resin to the carbon material powder is 100:(5~10); The carbon cloth has a basis weight of 300~400g / m². 2 The prepreg has a rubber content of 30-45 wt%. The number of layers is 14 to 20.

3. The preparation method according to claim 1, characterized in that, The molding process is set based on the DSC curve of the liquid resin. Specifically, the molding temperature is determined according to the DSC curve of the liquid resin. The molding temperature is lower than the temperature corresponding to the exothermic peak of the DSC curve but higher than the temperature at the beginning of the DSC curve. Multiple groups of liquid resin samples are cured at the molding temperature, with the curing time of each group of liquid resin samples progressively increased. The curing time of each group of cured liquid resin samples is determined based on the Tc of the cured product. g The value determines the optimal curing time, which is the molding process time.

4. The preparation method according to claim 1 or 3, characterized in that, The molding process comprises eleven stages, referred to sequentially as Stage 1 to Stage 11. Stage 1 is the heating stage, with a heating time of 69-71 minutes, a final temperature of 96-114°C, and a pressure of 0 MPa. Stage 2 is the heat preservation stage, with a heat preservation time of 29-31 minutes, a heat preservation temperature of 96-114°C, and a pressure of 0 MPa. Stage 3 is the heat preservation stage, with a heat preservation time of 1-3 minutes, a heat preservation temperature of 96-114°C, and a pressure of 0.05-0.15 MPa. Stage 4 is the heat preservation stage, with a heat preservation time of 1-3 minutes, a heat preservation temperature of 96-114°C, and a pressure of 0.25-0.35 MPa. Stage 5 is the heat preservation stage, with a heat preservation time of 1-3 minutes, a heat preservation temperature of 96-114°C, and a pressure of 0.45-0.55 MPa. Stage 6 is the heat preservation stage, with a heat preservation time of 1-3 minutes. The first stage is a holding stage, with a holding temperature of 96~114℃ and a pressure of 0.75~0.85MPa. The second stage is a holding stage, with a holding time of 2~4 minutes and a holding temperature of 96~114℃ and a pressure of 0.75~1.3MPa. The third stage is a heating stage, with a heating time of 49~51 minutes and a final temperature of 146~154℃ and a pressure of 0.75~1.3MPa. The fourth stage is a holding stage, with a holding time of 96~114℃ and a pressure of 0.75~0.85MPa. The fifth stage is a holding stage, with a holding time of 49~51 minutes and a final temperature of 146~154℃ and a pressure of 0.75~1.3MPa. The heating time is 29-31 minutes, the holding temperature is 146-154℃, and the pressure is 0.75-1.3 MPa; the tenth stage is the heating stage, the heating time is 59-61 minutes, the final temperature is 176-184℃, and the pressure is 0.75-1.3 MPa; the eleventh stage is the holding stage, the holding time is 84-86 minutes, the holding temperature is 176-184℃, and the pressure is 0.75-1.3 MPa.

5. The preparation method according to claim 1, characterized in that, The second impregnation temperature is 160~280℃, the pressure is 2~4MPa, and the time is 2~4h. After impregnation, the temperature is lowered to allow the asphalt to solidify.

6. The preparation method according to claim 1, characterized in that, The density of the carbon / carbon sheet is 1.5 g / cm³. 3 The above applies; if the density of the board obtained after the second carbonization is less than 1.5 g / cm³. 3 Then repeat the second impregnation and second carbonization process until the density of the resulting carbon / carbon sheet is 1.5 g / cm³. 3 above.

7. The carbon / carbon composite material prepared by the preparation method according to any one of claims 1 to 6.

8. A carbon / carbon PECVD support frame, characterized in that, It is prepared from the carbon / carbon composite material described in claim 7.

9. The method for preparing the carbon / carbon PECVD support frame according to claim 8, characterized in that, Includes the following steps: The carbon / carbon composite material described in claim 7 is precision machined to obtain the carbon / carbon PECVD support frame.

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