Carbon fiber sample preparation tool and method of preparing a carbon fiber sample

Abstract

The application provides a carbon fiber sample preparation tool and a carbon fiber sample preparation method, which comprise a first mold and a second mold, the first mold has a first groove, a carbon fiber bundle can enter the first groove and is pasted with a conductive tape in the first groove to form a carbon fiber pre-sample, the second mold has a second groove, the sidewall of the second groove has an opening, the second mold has a cutting surface outside the second groove, the cutting surface is a plane and is arranged around the circumference of the opening, the carbon fiber pre-sample can enter the second groove and can extend out of the opening, so that a cutting structure can cut the carbon fiber pre-sample along the cutting surface to obtain a carbon fiber sample, and a section of the carbon fiber sample forms a carbon fiber cross-section morphology microscopic observation surface. According to the carbon fiber sample preparation tool and the carbon fiber sample preparation method, the carbon fiber cross-section can be quickly obtained without damaging the carbon fiber cross-section.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of carbon fibers, and particularly relates to a carbon fiber sample preparation tool and a carbon fiber sample preparation method. BACKGROUND

[0002] At present, a scanning electron microscope is a high-efficiency tool for observing and analyzing the microstructure of various materials, and has the advantages of high resolution, wide magnification range, continuous adjustment, large imaging depth of field, etc. However, in actual engineering applications, the internal structure of many materials also needs to be observed and characterized, at which time the sample needs to be broken first, and then the cross-section fracture is observed and analyzed. According to the forming process, structural characteristics, etc. of various materials, the method for preparing the cross-section sample is also different. Common methods include physical breaking, ion beam cutting, liquid nitrogen brittle fracture, embedding after polishing, etc. The above methods are usually suitable for common materials that can be clamped or fixed using auxiliary tools.

[0003] However, for carbon fiber bundle samples with a single filament cross-section size less than 20 microns, the cross-section sample preparation usually uses methods such as liquid nitrogen brittle fracture, embedding after polishing, etc. The above methods have complicated sample preparation steps, high cost, require a large amount of consumables and rich experience, and the polishing operation on the surface of the embedded sample can easily damage the cross-section surface. At the same time, the above methods take a long time, which lags behind the guidance and reference for the process parameter adjustment and optimization of the carbon fiber industrial production line.

[0004] Therefore, how to provide a carbon fiber sample preparation tool and a carbon fiber sample preparation method capable of quickly obtaining a carbon fiber cross-section without damaging the carbon fiber cross-section has become a problem that needs to be solved by those skilled in the art. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to provide a carbon fiber sample preparation tool and a carbon fiber sample preparation method capable of quickly obtaining a carbon fiber cross-section without damaging the carbon fiber cross-section.

[0006] In order to solve the above problems, the present application provides a carbon fiber sample preparation tool, which comprises:

[0007] A first mold having a first groove; a carbon fiber bundle can enter the first groove and paste a conductive tape in the first groove to form a carbon fiber pre-sample;

[0008] and a second mold, the second mold having a second recess; the second recess having an opening on a side wall thereof; the second mold having a cutting surface, the cutting surface being located outside the second recess; the cutting surface being a plane, the cutting surface being arranged around a circumference of the opening; the carbon fiber pre-sample being capable of entering the second recess, and the carbon fiber pre-sample being capable of extending out of the opening, such that the cutting structure is capable of cutting the carbon fiber pre-sample along the cutting surface to obtain a carbon fiber sample; a section of the carbon fiber sample forming a microscopic observation surface.

[0009] Further, the opening is located on a first outer surface of the second mold, the first outer surface being a plane, the first outer surface forming the cutting surface;

[0010] Further, the second mold comprises a first structure and a second structure connected to each other; the first recess is formed in the first structure; a step is formed between the first structure and the second structure, the opening being located corresponding to a position of the step, such that the cutting structure is capable of moving towards the position close to the step when cutting the carbon fiber pre-sample along the cutting surface.

[0011] Further, the first recess comprises a first slot and a second slot connected to each other; the carbon fiber bundle is capable of entering the first slot; the conductive adhesive tape is capable of entering the second slot to be pasted on a surface of the carbon fiber bundle.

[0012] Further, the first slot is a first strip-shaped slot, and the second slot is a second strip-shaped slot, the first strip-shaped slot and the second strip-shaped slot having an included angle between extension directions thereof.

[0013] Further, the first strip-shaped slot and the second strip-shaped slot are perpendicular to each other in the extension directions thereof.

[0014] Further, the second mold comprises a first structure, the second recess being arranged on a surface of the first structure, and the second mold further comprises a limiting structure capable of limiting the carbon fiber bundle in the second recess.

[0015] Further, a longitudinal section of the second recess is a trapezoid, a bottom of the second recess forming an upper base of the trapezoid, and a slot opening of the second recess forming a lower base of the trapezoid.

[0016] Further, the limiting structure comprises a limiting block, the limiting block being adapted to the shape and size of the second recess.

[0017] According to still another aspect of the present application, a preparation method of a carbon fiber sample is provided, the carbon fiber sample being prepared by using the carbon fiber sample preparation tool described above; the method comprising the following steps:

[0018] Step (1): placing a carbon fiber bundle in the first recess of the first mold, and pasting a conductive adhesive tape on the carbon fiber bundle to form a carbon fiber pre-sample;

[0019] Step (2): placing the carbon fiber pre-sample into the second recess of the second mold, and making the carbon fiber pre-sample extend out of the opening;

[0020] Step (3): cutting the carbon fiber pre-sample along the opening with a cutting tool to obtain the carbon fiber sample.

[0021] Further, when the first groove comprises a first slot and a second slot, in step (1), placing the carbon fiber bundle in the first groove of the first mold, the step of pasting the conductive tape on the carbon fiber bundle further comprises the following steps:

[0022] placing the carbon fiber bundle in the first slot, then placing the first conductive tape in the second slot; pasting the first conductive tape on the first side of the carbon fiber bundle; then turning the carbon fiber bundle by 180° in the second slot, placing the second conductive tape in the second slot; pasting the second conductive tape on the second side of the carbon fiber bundle opposite to the first side.

[0023] The carbon fiber sample preparation tool and the method for preparing the carbon fiber sample provided by the present application can quickly obtain the carbon fiber cross section without damaging the carbon fiber cross section by pasting the conductive tape on the carbon fiber bundle and cutting the carbon fiber pre-sample along the cutting surface of the opening. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 FIG. 1 is a structural schematic diagram of a first mold in an embodiment of the present application;

[0025] Figure 2 FIG. 2 is a structural schematic diagram of a second mold in an embodiment of the present application;

[0026] Figure 3 FIG. 3 is a structural schematic diagram of a limiting structure in an embodiment of the present application;

[0027] Figure 4 FIG. 4 is a structural schematic diagram of a second mold in an embodiment of the present application;

[0028] Figure 5 FIG. 5 is a structural schematic diagram of a second mold in an embodiment of the present application;

[0029] Figure 6 FIG. 6 is a structural schematic diagram of a carbon fiber bundle in a second mold in an embodiment of the present application;

[0030] Figure 7 FIG. 7 is a sectional structural schematic diagram of a carbon fiber bundle and a conductive tape in an embodiment of the present application;

[0031] Figure 8 FIG. 8 is a connection structural schematic diagram of a carbon fiber bundle and a conductive tape in an embodiment of the present application;

[0032] Figure 9 FIG. 9 is a microstructure diagram of the section of the carbon fiber sample after cutting in Embodiment 1 of the present application;

[0033] Figure 10 Figure 2 is a microstructure diagram of the section of the carbon fiber sample after cutting in the embodiment 2 of the present application.

[0034] 1, carbon fiber bundle; 2, conductive tape; 21, first tape; 22, second tape; 3, first mold; 31, first groove; 311, first slot; 312, second slot; 4, second mold; 41, second groove; 42, cutting surface; 5, limiting structure. DETAILED DESCRIPTION

[0035] For reference Figures 1-10 As shown in Figure 1, a carbon fiber sampling tool includes a first mold 3 and a second mold 4. The first mold 3 has a first groove 31. A carbon fiber bundle 1 can enter the first groove 31 and paste a conductive tape 2 in the first groove 31 to form a carbon fiber pre-sample. The second mold 4 has a second groove 41. The sidewall of the second groove 41 has an opening. The second mold 4 has a cutting surface 42 outside the second groove 41. The cutting surface 42 is a plane and is arranged around the circumference of the opening. The carbon fiber pre-sample can enter the second groove 41 and extend out of the opening so that a cutting structure can cut the carbon fiber pre-sample along the cutting surface 42 to obtain a carbon fiber sample. The section of the carbon fiber sample forms a microscopic observation surface. The present application pastes the conductive tape 2 in the first groove 31 of the first mold 3 to form the carbon fiber pre-sample, then places the carbon fiber pre-sample into the second groove 41, and the carbon fiber pre-sample extends out of the opening. The cutting structure cuts the carbon fiber pre-sample along the cutting surface 42 to obtain the carbon fiber sample.

[0036] The section of the carbon fiber sample forms a microscopic observation surface. The conductive tape 2 ensures the overall electrical conductivity of the carbon fiber bundle sample. The whole sample preparation process is simple and efficient, greatly saves time under the premise of ensuring sample accuracy, can guide industrial production in time, and obtains the carbon fiber sample by cutting the carbon fiber pre-sample along the cutting surface 42. This can make the cutting section port, i.e., the section of the carbon fiber sample, smooth and flat. The cutting structure can be a knife, and further, the knife can be a scalpel. The cutting structure used for cutting the sample is not limited to a scalpel, but also includes other knives that can cut the PAN-based carbon fiber sample at one time. The carbon fiber bundle 1, i.e., the carbon fiber bundle, also includes pre-oxidized yarn, high-carbon yarn, low-carbon yarn, and other high-strength and high-modulus graphite fibers in carbon fiber production.

[0037] The present application can solve the problems of current sample preparation methods for observing the cross-sectional morphology of carbon fibers by scanning electron microscopy, such as complicated steps, long time consumption, even a certain degree of sample wear, and lag in guiding industrial production. It is convenient to observe the cross-sectional morphology of the carbon fiber bundle 1.

[0038] The application also discloses some embodiments, the opening is located on the first outer surface of the second mold 4, the first outer surface is a plane, and the first outer surface forms the cutting surface 42; the structure is simple, and the production process is simple.

[0039] The application also discloses some embodiments, the second mold 4 comprises a first structure and a second structure connected with each other; the first groove 31 is arranged on the first structure; a step is formed between the first structure and the second structure, and the position of the opening corresponds to the position of the step, so that the cutting structure quickly moves to the position close to the step when cutting the carbon fiber preform along the cutting surface 42. The cutting surface 42 of the application can not be worn, and cutting is convenient.

[0040] The application also discloses some embodiments, the first groove 31 comprises a first groove 311 and a second groove 312 connected with each other; the carbon fiber bundle 1 can enter the first groove 311; and the conductive adhesive tape 2 can enter the second groove 312 to paste the conductive adhesive tape on the surface of the carbon fiber bundle. That is, the conductive adhesive tape 2 is placed along the extension direction of the second groove 312, so that the carbon fiber bundle can be quickly and accurately pasted.

[0041] The application also discloses some embodiments, the first groove 311 is a first strip-shaped groove, the second groove 312 is a second strip-shaped groove, and the extension directions of the first strip-shaped groove and the second strip-shaped groove form an included angle. That is, the first mold 3 is a cuboid, and the upper surface of the first mold 3 comprises the first groove 311 and the second groove 312 which are perpendicular to each other; the extension direction of the first groove 311 is parallel to the extension direction of the long side of the upper surface, and the distance between the first groove 311 and the two long sides is the same; the extension direction of the center of the second groove 312 is parallel to the center line of the width direction; and the first groove 311 and the second groove 312 are connected at the intersection. The width of the first groove 311 is slightly larger than the width of the carbon fiber bundle, and is 1mm-8mm; the width of the second groove 312 is slightly larger than the width of the carbon conductive adhesive tape 2, and is 4mm-6mm; and the depth of the first groove 311 and the second groove 312 is the same, and is preferably 1mm-3mm. The conductive adhesive tape 2 can be placed longer in the second groove 312, and is pasted more firmly.

[0042] The application also discloses some embodiments, the extension directions of the first strip-shaped groove and the second strip-shaped groove are perpendicular to each other. In this way, the two conductive adhesive tapes 2 after being pasted are both perpendicular to the carbon fiber bundle 1, and are pasted more firmly and more beautifully.

[0043] The application also discloses some embodiments, the second mold 4 comprises a first structure, the second groove 41 is arranged on the surface of the first structure, and the second mold 4 further comprises a limiting structure 5 which can limit the carbon fiber bundle 1 in the second groove 41. The cutting can be smoothly performed, and the carbon fiber bundle 1 can be prevented from moving, so as to affect the cutting effect of the cutting surface.

[0044] The application further discloses some embodiments, the longitudinal section of the second groove 41 is a trapezoid, the groove bottom of the second groove 41 forms the lower base of the trapezoid, and the groove opening of the second groove 41 forms the upper base of the trapezoid. That is, the second groove 41 is a reverse trapezoidal groove shape, and the limiting block is a trapezoidal body matched with the shape and size of the first groove 31. The trapezoid is an isosceles trapezoid, the rear end surface of the second groove 41 is flush with the rear end surface of the base, and the groove length is 1 / 2 to 2 / 3 of the length of the base from the rear end surface to the front end surface. The surface of the second mold 4 except the reverse trapezoidal groove is a plane, wherein the horizontal height of the surface is flush with the bottom surface of the reverse trapezoidal groove.

[0045] The application further discloses some embodiments, the limiting structure 5 comprises a limiting block matched with the shape and size of the second groove 41. The shape and volume of the limiting block are the same as those of the second groove 41, and the limiting block is a trapezoidal body capable of filling the volume of the second groove 41. The trapezoidal body limiting structure 5 is matched with the base with the reverse trapezoidal groove to press the carbon fiber tows wrapped in the carbon conductive adhesive tape 2 in the groove, so that the tows are flat, the cross-section port after being quickly cut by a scalpel is flat and smooth, in addition, the cooperation of the limiting structure 5 and the cutting groove makes the clamp suitable for various specifications of carbon fiber tows and various intermediate products in the production of carbon fibers, such as pre-oxidized fibers, high-carbon fibers and low-carbon fibers, and is a sample preparation method for quickly and reliably observing the cross-sectional morphology of carbon fibers in a laboratory and industrial production.

[0046] The application further provides a carbon fiber sample preparation method, and the carbon fiber sample is prepared by using the carbon fiber sample preparation tool.

[0047] Step (1): placing the carbon fiber tows 1 in the first groove 31 of the first mold 3, and pasting the carbon fiber tows 1 with the conductive adhesive tape 2 to form carbon fiber pre-samples;

[0048] Step (2): placing the carbon fiber pre-samples in the second groove 41 of the second mold 4, and making the carbon fiber pre-samples extend out of the opening;

[0049] Step (3): cutting the carbon fiber pre-samples along the opening by using a cutting tool to obtain carbon fiber samples.

[0050] The application discloses a sample preparation fixture for scanning electron microscope observation of carbon fiber cross section morphology and a rapid sample preparation method. The sample preparation fixture comprises a sample preparation second mold 4 and a sample preparation first mold 3. The sample preparation second mold 4 is used for fixing a sample when rapidly cutting the carbon fiber and comprises a base and a limiting structure 5. The upper surface of the base is in the shape of an inverted trapezoidal groove, and the limiting structure 5 is a trapezoidal body matched with the groove shape and size. The sample preparation first mold 3 is used for pasting a carbon conductive tape 2 to the surface of the sample in the vertical direction of the carbon fiber axis and is in the shape of a cuboid, wherein the upper surface comprises two mutually perpendicular shallow grooves. The rapid sample preparation method is as follows: after pasting a layer of carbon conductive tape 2 on the upper and lower surfaces of the carbon fiber bundle in the width direction of the carbon fiber bundle by using the first mold 3, placing the carbon fiber bundle in the groove of the sample preparation second mold 4 and making the edges of the carbon conductive tape 2 close to the front end of the groove, then placing the limiting structure 5 into the groove to press the bundle, pressing the scalpel from top to bottom along the front end surface of the limiting structure 5 to cut the bundle, cutting the bundle on the other side of the carbon conductive tape 2, then taking out the bundle, and after subsequent operations such as gold spraying, the bundle can be used as a sample for scanning electron microscope observation of the cross section morphology of the carbon fiber.

[0051] Specifically, the rapid sample preparation steps are as follows:

[0052] Step S1: selecting a carbon fiber bundle with a proper appearance and cutting a length of 100-300 mm of the bundle as a preset sample; the length of the cut bundle is not limited to 100-300 mm.

[0053] Step S2: comprising S21, placing the preset sample in step S1 into the first groove 311 of the sample preparation first mold 3, making the axis of the preset sample parallel or coincident with the axis of the first groove 311, pasting the carbon conductive tape 2 (the conductive tape 2 is the first tape 21) to the surface of the preset sample in the extension direction of the second groove 312, and ensuring that the surface of the carbon conductive tape 2 is flat and wrinkle-free; S22, turning over the preset sample in the first groove 311, ensuring that the carbon conductive tape 2 (the conductive tape 2 is the first tape 21) is placed into the second groove 312 and the axes are parallel, repeating the process of pasting the carbon second tape 22 at the preset sample where the first tape 21 has been pasted, pasting the carbon conductive tape 22 at the preset sample where the carbon conductive tape 21 has been pasted after turning over, wrapping the preset sample at a certain position in the carbon conductive tapes 2 pasted on the upper and lower surfaces, and ensuring that the lengths of the first tape and the second tape are greater than the width of the carbon fiber sample and the horizontal projections are coincident; cutting the carbon conductive tapes at both ends of the carbon fiber sample beyond the carbon fiber sample to retain 2 mm to 3 mm;

[0054] Step S3: including S31, the sample with the carbon conductive tape 2 pasted in step S2 is placed in the groove of the horizontally placed sample preparation second mold 4, the filament axis direction is parallel to the groove axis direction, the side edge of the carbon conductive tape 2 is 0.5mm-1mm close to the groove edge, and does not exceed the front end surface of the groove; S32, the limiting structure 5 is placed in the groove, the front and rear end surfaces of the limiting structure 5 are flush with the front and rear end surfaces of the groove, and the carbon fiber tows placed in step 3 are compressed tightly to ensure that the tows cannot slide freely;

[0055] Step S4: including S41, using a scalpel, the tows are cut off from top to bottom along the front end surface of the limiting structure 5, the force is suitable for cutting off the tows at one time, and the scalpel blade avoids sliding forward and backward to cause the tows to spread out; S42, the limiting structure 5 is removed, the tows after cutting are reversed, and then the tows at the other end of the carbon conductive tape 2 are cut off in the same way according to the description of step S41.

[0056] Step S5: the tows after cutting in step S4 are taken out and can be used as a sample for observing the cross-sectional morphology of carbon fibers after gold spraying and subsequent operations.

[0057] Some embodiments of the application are also disclosed, when the first groove 31 includes the first slot 311 and the second slot 312, in step (1), the carbon fiber bundle 1 is placed in the first groove 31 of the first mold 3, and the carbon fiber bundle 1 is pasted with the conductive tape 2, which further includes the following steps:

[0058] The carbon fiber bundle 1 is placed in the first slot 311, then the first conductive tape is placed in the second slot 312, the first conductive tape is pasted on the first side of the carbon fiber bundle 1, then the carbon fiber bundle 1 is turned over 180° in the second slot 312, the second conductive tape is placed in the second slot 312, and the second conductive tape is pasted on the second side of the carbon fiber bundle 1 corresponding to the first side.

[0059] The application relates to a sample preparation clamp and a rapid sample preparation method for observing the cross-sectional morphology of carbon fibers by a scanning electron microscope. The sample preparation clamp comprises a sample preparation second mold 4 and a sample preparation first mold 3. The sample preparation second mold 4 is used for fixing a sample when the carbon fiber is rapidly cut, and comprises a base and a limiting structure 5. The upper surface of the base is in the shape of an inverted trapezoidal groove, and the limiting structure 5 is a trapezoidal body matching the groove shape and size. The sample preparation first mold 3 is used for vertically pasting a carbon conductive adhesive tape 2 to the surface of the sample along the axis direction of the carbon fiber, and the shape of the sample preparation first mold 3 is a cuboid, wherein the upper surface comprises two mutually perpendicular shallow grooves. The rapid sample preparation method is as follows: after a layer of carbon conductive adhesive tape 2 is pasted on the upper and lower surfaces of the carbon fiber bundle along the width direction of the carbon fiber bundle by using the first mold 3, the carbon fiber bundle is placed in the groove of the sample preparation second mold 4 and the edge of the conductive adhesive tape 2 is close to the front end of the groove, then the limiting structure 5 is placed into the groove to press the bundle, the bundle is cut by pressing a scalpel from top to bottom along the front end surface of the limiting structure 5, the bundle on the other side of the conductive adhesive tape 2 is cut, then the bundle is taken out, and after subsequent operations such as gold spraying, the bundle can be used as a sample for rapidly observing the cross-sectional morphology of the carbon fiber by the scanning electron microscope.

[0060] The second mold 4 comprises a base and a limiting structure 5. The upper surface of the base is in the shape of an inverted trapezoidal groove, and the limiting structure 5 is a trapezoidal body matching the groove shape and volume, and can fill the volume of the groove.

[0061] As an improved scheme of the application, the end surface of the inverted trapezoidal groove is an isosceles trapezoid, the rear end surface of the groove is flush with the rear end surface of the base, and the length of the groove is 1 / 2 to 2 / 3 of the length of the base from the rear end surface to the front end surface. Preferably, for the convenience of actual operation, the length of the groove is 2 / 3 of the length of the base.

[0062] As an improved scheme of the application, the surface of the second mold 4 is a smooth plane except the inner surface of the second groove 41, and the inner surface of the second groove 41 and the surface of the limiting structure 5 are both frosted surfaces. The roughness is set in the range of Ra0.8 to Ra1.6, and the effect of preventing sliding can be achieved.

[0063] The shape of the first mold 3 is a cuboid, and the upper surface comprises two mutually perpendicular first and second grooves 311 and 312.

[0064] As an improved scheme of the application, the axis of the first groove 311 is parallel to the long side direction of the upper surface, and the distance from the first groove 311 to the two long sides is the same. The axis of the second groove 312 is parallel to the center line of the wide side direction, and the first groove 311 and the second groove 312 are interconnected at the intersection.

[0065] As an improved scheme of the application, the distance between the second groove 312 and the right wide side is 1 / 3 to 1 / 2 of the length of the long side. Preferably, for the convenience of actual operation, the distance is 1 / 3 of the length of the long side.

[0066] As an improvement of the present application, the width of the first groove 311 is greater than the width of the carbon fiber tows by 1-2 mm, the width of the second groove 312 is greater than the width of the carbon conductive adhesive tape 2 by 1-2 mm, the depth of the first groove 311 and the second groove 312 is the same, and preferably, 1-3 mm is the best. Preferably, the width of the first groove 311 is 1-8 mm, the depth of the first groove 311 is 1-2 mm greater than the thickness of the tows, and the width of the second groove 312 is 4-6 mm. The inner surface of the first groove 311 and the second groove 312 of the present application is designed to have a frosted effect, which can avoid the adhesion of the conductive adhesive tape to the inner surface of the first groove 311 or the second groove 312.

[0067] The present application also provides a rapid sample preparation method for observing the cross-sectional morphology of carbon fibers by scanning electron microscopy, which comprises using the sample preparation second mold 4, the sample preparation first mold 3 and the rapid sample preparation method disclosed in the present application. The rapid sample preparation method comprises the following steps: S1, selecting a sample tow with a suitable appearance; S2, using the first mold 3 to vertically paste the conductive adhesive tape 2 on the upper and lower surfaces of the sample tow; S3, placing the sample tow with the conductive adhesive tape 2 pasted into the second mold 4 and pressing the sample tow with the limiting structure 5; S4, using a scalpel to quickly cut the sample tow along the surface of the limiting structure 5, and quickly cutting the other end of the sample tow in the same way; S5, taking out the cut sample tow, which can be used as a scanning electron microscopy sample after gold spraying and other operations for cross-sectional morphology observation.

[0068] Step S1: selecting a carbon fiber tow with a suitable appearance, and cutting a sample of 100-300 mm in length;

[0069] Step S2: comprising S21, placing the sample prepared in step S1 into the first groove 311 of the sample preparation first mold 3, making the axis of the sample prepared parallel or coinciding with the axis of the first groove 311, and pasting the carbon conductive adhesive tape 2 to the surface of the sample prepared along the axis direction of the second groove 312, ensuring that the surface of the carbon conductive adhesive tape 2 is flat and wrinkle-free; S22, turning over the sample prepared in the first groove 311, ensuring that the carbon conductive adhesive tape 2 is placed into the second groove 312 and the axes are parallel, repeating the process of pasting the carbon conductive adhesive tape 2 on the sample prepared with the carbon conductive adhesive tape 2 pasted, so that the sample prepared is wrapped in the carbon conductive adhesive tape 2 pasted on the upper and lower surfaces, and the sizes of the carbon conductive adhesive tapes 2 on the upper and lower surfaces are the same and the horizontal projections are coinciding; cutting the ends of the carbon conductive adhesive tape 2 beyond the carbon fiber sample, and retaining 2-3 mm;

[0070] Step S3: including S31, the sample with carbon conductive tape 2 pasted in step S2 is placed in the groove of the horizontally placed sample preparation second mold 4, the filament axis direction is parallel to the groove axis direction, the side edge of the carbon conductive tape 2 is close to the groove edge 0.5mm-1mm, and does not exceed the front end surface of the groove; S32, the limiting structure 5 is put into the groove, the front and rear end surfaces of the limiting structure 5 are flush with the front and rear end surfaces of the groove, and the carbon fiber tows placed in step 3 are compressed tightly to ensure that the tows cannot slide freely;

[0071] Step S4: including S41, using a scalpel, the tows are cut off from top to bottom along the front end surface of the limiting structure 5, the force is appropriate to cut off the tows at one time, and the scalpel is avoided to slide forward and backward to cause the tows to spread; S42, the limiting structure 5 is removed, the tows after cutting are reversed, and then the tows at the other end of the carbon conductive tape 2 are cut off in the same way according to the description of step S41.

[0072] Step S5: the tows after cutting in step S4 are taken out and can be used as a sample for observing the cross-sectional morphology of carbon fibers after gold spraying and subsequent operations.

[0073] As an improved scheme of the present application, in step S1, the length of the pre-prepared sample is just the length between the front and rear end surfaces of the clamp base, which is the best.

[0074] As an improved scheme of the present application, in step S21, when the carbon conductive tape 2 is pasted on the carbon fiber tows, it should be pasted flat on the surface of the tows, and the width direction of the tows should be flat, preferably, the sample without overlapping and with no hair should be selected.

[0075] As an improved scheme of the present application, in step S22, the carbon conductive tape 2 is pasted on the other side of the sample, which should be aligned with the edge of the carbon conductive tape 2 in step S21, which is beneficial to subsequent cutting.

[0076] 1. The process of pasting the conductive tape, the carbon fiber pre-prepared sample is first placed in the groove along the first groove 311 axis, and then the carbon conductive tape is pasted to the surface of the carbon fiber sample along the extension direction of the second groove 312. Only the tape is pasted on the carbon fiber sample during pasting, the second groove 312 actually plays a role in directing the carbon conductive tape, and then the carbon fiber sample is flipped and the above process is repeated. At this time, part of the first pasted carbon conductive tape will be pasted to the surface of the groove, but it will not affect the overall pasting effect; for example, the first pasted conductive tape is the first tape 21, and the flipped and pasted conductive tape is the second tape 22. In this way, the first tape and the second tape are bonded to form a ring-shaped pasting structure.

[0077] 2. Because the carbon conductive tape is pasted on the upper and lower surfaces of the carbon fiber sample once, and each time the carbon conductive tape pasted exceeds the width of the carbon fiber sample, the carbon conductive tape pasted on the upper and lower surfaces of the carbon fiber sample is not overlapped, and the carbon conductive tape pasted on the upper and lower surfaces of the carbon fiber sample is not overlapped.Figure 7 The conductive adhesive tape 2 marked in the middle is actually the overall effect of the upper and lower surfaces of the carbon fiber sample after being pasted twice. The upper and lower two layers of carbon conductive adhesive tape with the width of the carbon fiber sample are bonded together, and finally exhibit a ring shape, which can better wrap the carbon fiber sample.

[0078] Example 1:

[0079] Rapid preparation of cross-section samples of high-strength PAN-based carbon fibers for scanning electron microscope observation

[0080] The embodiment provides a sample preparation clamp suitable for observing the cross-sectional morphology of carbon fibers by a scanning electron microscope, which comprises a sample preparation second mold 4 and a sample preparation first mold 3.

[0081] Preferably, the sample preparation second mold 4 for carbon fiber tow material scanning electron microscope cross-section preparation comprises a base and a limiting structure 5, wherein the upper surface of the base is in the shape of an inverted trapezoidal groove, and the limiting structure 5 is a trapezoidal body with the same volume as the groove shape, which can fill the volume of the groove.

[0082] Preferably, the end surface of the inverted trapezoidal groove is an isosceles trapezoid, the rear end surface of the groove is flush with the rear end surface of the base, and the length of the groove is 1 / 2 to 2 / 3 of the length of the base from the rear end surface to the front end surface. Preferably, for the convenience of actual operation, the length of the groove in the embodiment is 2 / 3 of the length of the base.

[0083] Preferably, the surface of the base is a smooth plane except the groove surface, and the surfaces of the groove and the limiting structure 5 are frosted surfaces to prevent the limiting structure 5 from slipping when it is put into the groove.

[0084] Preferably, the sample preparation first mold 3 for carbon fiber tow material scanning electron microscope cross-section preparation is in the shape of a cuboid, and the upper surface comprises two first grooves 311 and second grooves 312 with their axes perpendicular to each other.

[0085] Preferably, the axis of the first groove 311 is parallel to the long edge direction of the upper surface, the two sides of the first groove 311 are equidistant from the two long edges of the first mold 3, the axis of the second groove 312 is parallel to the center line of the wide edge direction, and the two sides of the second groove 312 are equidistant from the two short edges of the first mold 3. The first groove 311 and the second groove 312 communicate with each other at the intersection.

[0086] Preferably, the distance between the second groove 312 and the right wide edge is 1 / 3 to 1 / 2 of the length of the long edge. For the convenience of actual operation, the distance in the embodiment is 1 / 3 of the length of the long edge.

[0087] As an improvement of the present application, the width of the first groove 311 is greater than the width of the carbon fiber tow by 1mm-2mm, the width of the second groove 312 is greater than the width of the carbon conductive tape 2 by 1mm-2mm, and the depth of the first groove 311 and the second groove 312 is the same. Preferably, the depth of the shallow groove in the present embodiment is 3mm, the width of the first groove 311 is 6mm, and the width of the second groove 312 is 6mm.

[0088] The above preferred embodiments can be combined to obtain an optimal implementation. The present embodiment also provides a rapid sample preparation method for observing the cross-sectional morphology of carbon fibers using a scanning electron microscope based on the optimal implementation described above, characterized by comprising the following steps:

[0089] Step S1: Select a high-modulus carbon fiber sample with good appearance, and cut a length of 200mm of the tow as a preset sample;

[0090] Step S2: Place the preset sample described in step S1 in the first groove 311 of the sample preparation first mold 3, with the axis of the preset sample parallel or coinciding with the axis of the first groove 311. Paste the carbon conductive tape 2 along the axis direction of the second groove 312 to the surface of the preset sample, ensuring that the surface of the carbon conductive tape 2 is flat and wrinkle-free. Turn the preset sample in the first groove 311 to ensure that the carbon conductive tape 2 is placed in the second groove 312 with their axes parallel. Repeat the above process of pasting the carbon conductive tape 2 on the preset sample to which the carbon conductive tape 2 has been pasted, so that the preset sample is wrapped in the carbon conductive tape 2 pasted on the upper and lower surfaces. The upper and lower carbon conductive tapes 2 have the same size and their horizontal projections coincide. Cut off the ends of the carbon conductive tape 2 that exceed the carbon fiber sample, leaving 2mm-3mm;

[0091] Step S3: Place the tow sample with the carbon conductive tape 2 pasted in step S2 in the groove of the sample preparation clamp, with the axis direction of the tow parallel to the axis direction of the groove, ensuring that the side edges of the carbon conductive tape 2 on the tow are located at the inner edges of the groove without exceeding the front end surface of the groove;

[0092] Step S4: Place the trapezoidal limiting structure 5 into the groove of the sample preparation clamp, press the limiting structure 5 with your hand, and then quickly cut the tow from top to bottom along the edge of the limiting structure 5 using a scalpel. Then, reverse the position of the tow before and after it is taken out, and cut the other end of the tow that has not been cut according to this step:

[0093] Step S5: Take out the tow, and the carbon fiber cross-sectional sample is quickly prepared. The top view of the prepared sample is shown in Figure 7 ;

[0094] After the carbon fiber cross-sectional sample is sprayed with gold, it is observed using a scanning electron microscope, and the scanning image is shown in Figure 9 .

[0095] Example 2:

[0096] Rapid preparation of cross-section sample of low carbon filament used for scanning electron microscope observation in PAN-based carbon fiber production

[0097] The embodiment provides a sample preparation clamp suitable for scanning electron microscope observation of low carbon filament cross-section morphology, which comprises a sample preparation second mold 4 and a sample preparation first mold 3.

[0098] Preferably, the sample preparation second mold 4 for scanning electron microscope cross-section of low carbon filament bundle material comprises a base and a limiting structure 5, wherein the upper surface of the base is in the shape of an inverted trapezoidal groove, the limiting structure 5 is in the shape of a trapezoidal body with the same volume as the groove, and the limiting structure 5 can fill the volume of the groove.

[0099] Preferably, the end surface of the inverted trapezoidal groove is an isosceles trapezoid, the rear end surface of the groove is flush with the rear end surface of the base, and the length of the groove is 1 / 2 to 2 / 3 of the length of the base from the rear end surface to the front end surface, preferably, in order to facilitate actual operation, the length of the groove in the embodiment is 2 / 3 of the length of the base.

[0100] Preferably, the surface of the base is a smooth plane except the groove surface, and the surfaces of the groove and the limiting structure 5 are frosted surfaces to prevent the limiting structure 5 from slipping when being put into the groove.

[0101] Preferably, the sample preparation first mold 3 for scanning electron microscope cross-section of low carbon filament bundle material is in the shape of a cuboid, and the upper surface comprises a first groove 311 and a second groove 312 which are perpendicular to each other.

[0102] Preferably, the axis of the first groove 311 is parallel to the long edge direction of the upper surface, the two sides of the first groove 311 are equidistant from the two long edges of the first mold 3, the axis of the second groove 312 is parallel to the center line of the wide edge direction, and the two sides of the second groove 312 are equidistant from the two short edges of the first mold 3, and the first groove 311 and the second groove 312 are interconnected at the intersection.

[0103] Preferably, the distance between the second groove 312 and the right wide edge is 1 / 3 to 1 / 2 of the length of the long edge, and in order to facilitate actual operation, the distance in the embodiment is 1 / 3 of the length of the long edge.

[0104] As an improved scheme of the present application, the width of the first groove 311 is greater than the width of the carbon fiber bundle by 1mm-2mm, the width of the second groove 312 is greater than the width of the carbon conductive adhesive tape 2 by 1mm-2mm, and the depths of the first groove 311 and the second groove 312 are the same. Preferably, the depth of the shallow groove in the embodiment is 3mm, the width of the first groove 311 is 6mm, and the width of the second groove 312 is 6mm.

[0105] The above preferred embodiments can be combined to obtain an optimal embodiment. The present embodiment also provides a rapid sample preparation method for observing the cross-sectional morphology of low-carbon wire using a scanning electron microscope, based on the optimal embodiment described above, characterized by comprising the following steps:

[0106] Step S1: Select a low-carbon wire sample with good appearance, no hair and hair ball, and good bundling, cut a length of 200 mm of the wire bundle as a preset sample, and gently stretch the whole wire bundle and then use adhesive tape to stick the two ends of the wire bundle to ensure that the wire bundle does not spread out;

[0107] Step S2: Place the preset sample described in step S1 in the first groove 311 of the sample preparation first mold 3, fix the preset sample at both ends of the first groove 311 using adhesive tape or double-sided adhesive tape to make the axis of the preset sample parallel or coincident with the axis of the first groove 311, then paste the carbon conductive tape 2 to the surface of the preset sample along the axis direction of the second groove 312 to ensure that the surface of the carbon conductive tape 2 is flat and wrinkle-free, turn the preset sample in the first groove 311 to ensure that the carbon conductive tape 2 is placed in the second groove 312 and the axes thereof are parallel, and repeat the process of pasting the carbon conductive tape 2 on the preset sample that has been pasted with the carbon conductive tape 2 to wrap the preset sample in the carbon conductive tape 2 pasted on the upper and lower surfaces, and the upper and lower carbon conductive tapes 2 are of the same size and horizontally overlap; Figure 8 ;

[0108] Step S3: Place the pre-oxidized wire bundle sample treated in step S2 in the recess of the sample preparation clamp, stretch the wire bundle, and make the axis direction of the wire bundle parallel to the axis direction of the recess to ensure that the side edge of the carbon conductive tape 2 pasted on the wire bundle is located at the inner edge of the recess and does not exceed the front end surface of the recess;

[0109] Step S4: Place the ladder-shaped limiting structure 5 into the recess of the sample preparation clamp to press the wire bundle sample, and then use a scalpel to quickly cut the wire bundle from top to bottom along the edge of the limiting structure 5; then take out the wire bundle, reverse it and stretch it, and cut the wire bundle again according to this step at the other end that has not been cut:

[0110] Step S5: Finally, take out the wire bundle, and the cross-sectional sample is quickly prepared;

[0111] After the low-carbon wire cross-sectional sample is sprayed with gold, it is observed using a scanning electron microscope, and the scanning image is shown in Figure 10 .

[0112] Those skilled in the art will readily understand that the above advantageous modes can be freely combined and superimposed without conflict.

[0113] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application. The above is merely the preferred embodiment of the present application, it should be pointed out that, for the ordinary skilled in the art, without departing from the technical principle of the present application, a number of improvements and variations can be made, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. A carbon fiber sampling tool, characterized by, The application relates to a carbon fiber sample preparation device and a carbon fiber sample preparation method. The device comprises a first mold (3) and a second mold (4). The first mold (3) has a first groove (31), and a carbon fiber bundle (1) can enter the first groove (31) and stick to a conductive adhesive tape (2) in the first groove (31) to form a carbon fiber pre-sample. The first groove (31) comprises a first slot (311) and a second slot (312) which are connected to each other. The carbon fiber bundle (1) can enter the first slot (311). The conductive adhesive tape (2) can enter the second slot (312) to stick to the surface of the carbon fiber bundle (1).

2. The carbon fiber sampling tool of claim 1, wherein The second mold (4) has a second groove (41) with an opening on the side wall. The second mold (4) has a cutting surface (42) which is located outside the second groove (41).

3. The carbon fiber sampling tool of claim 1, wherein The cutting surface (42) is a plane and is arranged around the periphery of the opening.

4. The carbon fiber sampling tool of claim 3, wherein, The carbon fiber pre-sample can enter the second groove (41) and extend out of the opening, so that a cutting structure can cut the carbon fiber pre-sample along the cutting surface (42) to obtain a carbon fiber sample.

5. The carbon fiber sampling tool of claim 1, wherein The cutting surface of the carbon fiber sample forms a microscopic observation surface.

6. The carbon fiber sampling tool of claim 5, wherein, The first side and the second side of the carbon fiber pre-sample are both pasted with the conductive adhesive tape (2).

7. The carbon fiber sampling tool of claim 5, wherein The conductive adhesive tape (2) is pasted on the carbon fiber bundle (1) and is bonded together to prevent the carbon fiber bundle (1) from being scattered and to ensure the conductivity of the carbon fiber sample.

8. A method of preparing a carbon fiber sample using a carbon fiber sample preparation tool according to any one of claims 1 to 6, characterized in that, The opening is located on a first outer surface of the second mold (4). The first outer surface is a plane and forms the cutting surface (42). The second mold (4) comprises a first structure and a second structure which are connected to each other. The first groove (31) is arranged on the first structure. A step is formed between the first structure and the second structure. The position of the opening corresponds to the position of the step. When the cutting structure cuts the carbon fiber pre-sample along the cutting surface (42), the cutting structure moves towards the position close to the step. The first slot (311) is a first strip-shaped slot, and the second slot (312) is a second strip-shaped slot. The extension directions of the first strip-shaped slot and the second strip-shaped slot form an included angle. The extension directions of the first strip-shaped slot and the second strip-shaped slot are perpendicular to each other. The second mold (4) comprises a first structure, and the second groove (41) is arranged on the surface of the first structure. The second mold (4) further comprises a limiting structure (5) which can limit the carbon fiber bundle (1) in the second groove (41). The longitudinal section of the second groove (41) is a trapezoid. The bottom of the second groove (41) forms the upper base of the trapezoid. The slot opening of the second groove (41) forms the lower base of the trapezoid. The limiting structure (5) comprises a limiting block which is matched with the shape and size of the second groove (41). The method comprises the following steps: Step (1): placing the carbon fiber bundle (1) in the first recess (31) of the first mold (3), and sticking the conductive adhesive tape (2) to the carbon fiber bundle (1) to form a carbon fiber pre-sample; Step (2): placing the carbon fiber pre-sample into the second recess (41) of the second mold (4) and making the carbon fiber pre-sample extend out of the opening; Step (3): cutting the carbon fiber pre-sample along the opening by using a cutting tool to obtain a carbon fiber sample.

9. The method for preparing the carbon fiber sample according to claim 8, characterized in that, When the first recess (31) comprises a first groove (311) and a second groove (312), in the step (1), the placing the carbon fiber bundle (1) in the first recess (31) of the first mold (3) and sticking the conductive adhesive tape (2) to the carbon fiber bundle (1) further comprises the following steps: placing the carbon fiber bundle (1) into the first groove (311); then placing a first conductive adhesive tape into the second groove (312); sticking the first conductive adhesive tape to a first side of the carbon fiber bundle (1); then turning the carbon fiber bundle (1) by 180° in the second groove (312), placing a second conductive adhesive tape into the second groove (312); and sticking the second conductive adhesive tape to a second side of the carbon fiber bundle (1) opposite to the first side.

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