A method of splicing silicon carbide fibers

Abstract

A method for splicing silicon carbide fibers involves first using a silicon carbide fiber bundle B as a base rope. A1 bundle of fibers is rotated clockwise around the base rope once, forming a first loop between A1 and the base rope. A2 bundle of fibers is then passed through this first loop, and A1 is tightened, locking A2 within the first loop. Next, A2 bundle of fibers is rotated counter-clockwise around the base rope once, forming a second loop between A2 and the base rope. A1 bundle of fibers is then passed through this second loop, and A2 is tightened, locking A1 within the second loop. This process is repeated until A1 and A2 bundles can no longer form loops around the base rope. Then, silicon carbide fiber bundle A is used as the base rope, and B1 and B2 bundles are braided with the base rope in the same manner. This invention can lengthen pre-oxidized fibers through splicing, effectively solving problems such as fuzz and stress damage at the joint during the splicing process.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide fiber production technology, and in particular to a method for splicing silicon carbide fibers. Background Technology

[0002] Currently, the common continuous silicon carbide fiber preparation process involves four major steps: precursor synthesis, melt spinning, pre-oxidation treatment, and high-temperature sintering. Because silicon carbide fiber is brittle, the pre-oxidation stage releases a large amount of heat, easily leading to localized melting and coalescence. To ensure smooth pre-oxidation and fiber uniformity, the pre-oxidation process limits the length of silicon carbide fibers to approximately 2000m. However, continuous production of downstream silicon carbide fiber products requires frequent shutdowns for fiber splicing and restarting, hindering continuous production, placing high demands on production equipment, and increasing labor costs. Therefore, there is an urgent need for a method to splice and lengthen pre-oxidized silicon carbide fibers to produce ultra-long finished silicon carbide fibers for production. This method could reduce repeated spinning processes, effectively improve production efficiency, and lower production costs.

[0003] The most common existing method for splicing fibers is the use of air splicers. The principle is to use the combined action of pneumatic power and mechanical components to first untwist and then splice the ends of two fiber bundles. Specifically, the two fiber bundles are introduced into the splicer and clamped, excess fibers are cut off, and a high-frequency airflow is used to loosen the two fibers. Then, an airflow from the splicing chamber splices them together, completing the splicing action. Using this type of air splicer, the strength at the fiber joint can reach up to about 90% of the tensile strength of the fiber bundle itself.

[0004] However, because silicon carbide fiber is a particularly brittle fiber, after being spliced ​​by an air splicer, a large number of fuzzy fibers are generated at the splice, disrupting the stress between the silicon carbide fibers and resulting in low bundle strength at the joint. This makes the splicing effect of brittle fibers poor. On the one hand, in subsequent applications of the fiber bundle, such as weaving, it passes through numerous ceramic eyelets, yarn guides, reeds, and other components, where the fuzzy fibers increase further due to friction, affecting product quality and production efficiency. On the other hand, silicon carbide fiber is often used in cutting-edge defense fields such as aerospace, nuclear energy, and weaponry, where extremely high requirements are placed on the strength and uniformity of the fiber bundle. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a method for splicing silicon carbide fibers that prevents fuzz from forming during the splicing process and improves the strength of the spliced ​​fibers.

[0006] To achieve the above objectives, the present invention first proposes a method for splicing silicon carbide fibers, which specifically includes the following steps:

[0007] S1. Divide the silicon carbide fiber bundle A, which needs to be spliced, into two bundles and label them as bundle A1 and bundle A2 respectively. Label the connection point of bundle A1 and bundle A2 as end A3. Divide the silicon carbide fiber bundle B, which needs to be spliced, into two bundles and label them as bundle B1 and bundle B2 respectively. Label the connection point of bundle B1 and bundle B2 as end B3.

[0008] S2. Initially connect silicon carbide fiber bundle A and silicon carbide fiber bundle B.

[0009] The connecting ends of silicon carbide fiber bundle A and silicon carbide fiber bundle B are cross-inserted so that end A3 contacts end B3. A1 and A2 bundles are placed on both sides of silicon carbide fiber bundle B, and B1 and B2 bundles are placed on both sides of silicon carbide fiber bundle A. Then end A3 and end B3 are fixed.

[0010] S3. Begin knotting. The knotting method is as follows:

[0011] First, use silicon carbide fiber bundle B as the base rope. Rotate bundle A1 clockwise around the base rope once, forming a first loop between bundle A1 and the base rope. Pass bundle A2 through the first loop and tighten bundle A1, locking bundle A2 inside the first loop. Then, rotate bundle A2 counterclockwise around the base rope once, forming a second loop between bundle A2 and the base rope. Pass bundle A1 through the second loop and tighten bundle A2, locking bundle A1 inside the second loop. Repeat this process until bundles A1 and A2 can no longer form loops around the base rope. Then, use silicon carbide fiber bundle A as the base rope and braid bundles B1 and B2 with the base rope in the same manner.

[0012] In this embodiment, the lengths of the A1 bundle, A2 bundle, B1 bundle, and B2 bundle are 5cm to 20cm, preferably 10cm.

[0013] In this embodiment, when the A1 bundle, A2 bundle, B1 bundle, and B2 bundle form a knot, their bending angle is 30 to 60°, preferably 45°.

[0014] In this embodiment, in step S2, the positions of ends A3 and B3 are fixed by clamps attached to silicon carbide fiber bundles A and B.

[0015] In this embodiment, the silicon carbide fiber bundle A and silicon carbide fiber bundle B are prepared by sequentially synthesizing polycarbosilane precursors through high-temperature pyrolysis, melt spinning, and pre-oxidation treatment.

[0016] In this embodiment, the silicon carbide fiber bundle A and silicon carbide fiber bundle B are prepared by sequentially synthesizing polycarbosilane precursors through high-temperature pyrolysis, melt spinning, pre-oxidation treatment, and high-temperature sintering.

[0017] In this embodiment, the silicon carbide fiber bundle A and silicon carbide fiber bundle B are prepared by sequentially synthesizing polycarbosilane precursors through high-temperature pyrolysis, melt spinning, pre-oxidation treatment, high-temperature sintering treatment, and winding.

[0018] By employing the above method, the present invention has the following beneficial effects:

[0019] 1. The splicing method used in this invention is simple to operate, causes less stress damage between silicon carbide fibers at the splice joint, and can better improve the strength at the joint. Compared with air splicing, there are no obvious fuzzy fibers and the splicing strength is better.

[0020] 2. The splicing method used in this invention effectively reduces fuzz at the joint, and the fibers have strong cohesion after braiding, with virtually no obvious fuzz.

[0021] 3. The splicing method used in this invention can be applied to splicing fibers at multiple stages after pre-oxidation.

[0022] 4. Using the splicing method of the present invention, silicon carbide fibers of the required length can be prepared according to customer customization needs. At the same time, it can be applied to the continuous preparation of silicon carbide fibers to manufacture finished products such as silicon carbide fiber cloth, which can effectively save processes and reduce manufacturing costs. Attached Figure Description

[0023] Figure 1 This refers to the knotting state during step S2 of the present invention.

[0024] Figure 2 This refers to the knitting state during step S3 of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0027] Example 1:

[0028] like Figure 1 As shown, the present invention includes a method for splicing silicon carbide fibers, specifically comprising the following steps:

[0029] S1. Divide the silicon carbide fiber bundle A, which needs to be spliced, into two bundles and label them A1 and A2 respectively. Label the connection point of the A1 and A2 bundles as A3. Divide the silicon carbide fiber bundle B, which needs to be spliced, into two bundles and label them B1 and B2 respectively. Label the connection point of the B1 and B2 bundles as B3. The lengths of the A1, A2, B1, and B2 bundles are 10cm.

[0030] S2. Initially connect silicon carbide fiber bundle A and silicon carbide fiber bundle B.

[0031] The connecting ends of silicon carbide fiber bundle A and silicon carbide fiber bundle B are cross-inserted so that end A3 contacts end B3. A1 and A2 bundles are placed on both sides of silicon carbide fiber bundle B, and B1 and B2 bundles are placed on both sides of silicon carbide fiber bundle A. Then end A3 and end B3 are fixed. In this embodiment, the positions of end A3 and end B3 are fixed by clips clamped on silicon carbide fiber bundle A and silicon carbide fiber bundle B.

[0032] S3. Begin knotting. The knotting method is as follows:

[0033] First, using silicon carbide fiber bundle B as the base rope, filament A1 rotates clockwise around the base rope once, forming a first loop between filament A1 and the base rope. Filament A2 is then passed through this first loop, and filament A1 is tightened, locking it within the first loop. Next, filament A2 rotates counter-clockwise around the base rope once, forming a second loop. Filament A1 is then passed through this second loop, and filament A2 is tightened, locking it within the second loop. This process is repeated until filaments A1 and A2 can no longer form loops around the base rope. Then, using silicon carbide fiber bundle A as the base rope, filament B1 rotates clockwise around the base rope once... A first loop is formed between the A1 and B2 bundles and the base rope. The B2 bundle is passed through the first loop, and the B1 bundle is tightened, locking the B2 bundle inside the first loop. Then, the B2 bundle rotates counterclockwise around the base rope once, forming a second loop between the B2 bundle and the base rope. The B1 bundle is then passed through the second loop, and the B2 bundle is tightened, locking the B1 bundle inside the second loop. This process is repeated until the B1 and B2 bundles can no longer form loops around the base rope. During the above knitting, the A1, A2, B1, and B2 bundles bend at a 45° angle when forming a knot, thereby preventing the silicon carbide fiber from breaking due to excessive bending angle.

[0034] In this embodiment, the silicon carbide fiber bundle A and silicon carbide fiber bundle B are prepared by sequentially synthesizing polycarbosilane precursors through high-temperature pyrolysis, melt spinning, and pre-oxidation treatment.

[0035] The bundle strength and bundle tensile strength of three types of braided silicon carbide fibers—unknotted fibers (i.e., normal fibers), air-spun fibers, and fibers braided using this method—were tested. The test results are shown in the table below.

[0036]

[0037] As can be seen from the table above, the silicon carbide fiber strength retention rate and bundle tensile strength retention rate after being connected using this silicon carbide fiber splicing method are both above 90%, meeting the requirements of subsequent processes.

[0038] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural transformations made under the concept of the present invention using the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method of splicing silicon carbide fibers, comprising: Specifically comprising the following steps, S1, the connecting end of the silicon carbide fiber bundle A that needs to be connected is divided into two bundles of filaments and marked as A1 bundle of filaments and A2 bundle of filaments, and the connecting end of the silicon carbide fiber bundle B that needs to be connected is also divided into two bundles of filaments and marked as B1 bundle of filaments and B2 bundle of filaments, and the connecting end of the A1 bundle of filaments and the A2 bundle of filaments is marked as A3 end; S2, the silicon carbide fiber bundle A and the silicon carbide fiber bundle B are preliminarily connected, The connecting end of the silicon carbide fiber bundle A and the connecting end of the silicon carbide fiber bundle B are cross-inserted and installed, so that the A3 end and the B3 end are in contact, and the A1 bundle of filaments and the A2 bundle of filaments are arranged on both sides of the silicon carbide fiber bundle B, and the B1 bundle of filaments and the B2 bundle of filaments are arranged on both sides of the silicon carbide fiber bundle A, and then the A3 end and the B3 end are fixed; S3, start braiding, and the braiding mode is as follows: First, the silicon carbide fiber bundle B is taken as a base rope, the A1 bundle of filaments is rotated one circle clockwise around the base rope, the first rope loop is formed between the A1 bundle of filaments and the base rope, the A2 bundle of filaments is passed through the first rope loop, the A1 bundle of filaments is tightened, so that the A2 bundle of filaments is locked in the first rope loop, then the A2 bundle of filaments is rotated one circle counterclockwise around the base rope, the second rope loop is formed between the A2 bundle of filaments and the base rope, the A1 bundle of filaments is passed through the second rope loop, the A2 bundle of filaments is tightened, so that the A1 is locked in the second rope loop, and the cycle is repeated in sequence until the A1 bundle of filaments and the A2 bundle of filaments cannot form rope loops around the base rope; then the silicon carbide fiber bundle A is taken as a base rope, and the B1 bundle of filaments and the B2 bundle of filaments are braided with the base rope in the above mode.

2. The silicon carbide fiber splicing method according to claim 1, characterized by: The length of the A1 bundle of filaments, the A2 bundle of filaments, the B1 bundle of filaments and the B2 bundle of filaments is 5cm-20cm.

3. The silicon carbide fiber splicing method according to claim 2, characterized by: The length of the A1 bundle of filaments, the A2 bundle of filaments, the B1 bundle of filaments and the B2 bundle of filaments is 10cm.

4. The silicon carbide fiber splicing method according to claim 1, characterized by: The self-bending angle of the A1 bundle of filaments, the A2 bundle of filaments, the B1 bundle of filaments and the B2 bundle of filaments when forming a knot is 30°-60°.

5. The silicon carbide fiber splicing method according to claim 4, characterized by: The self-bending angle of the A1 bundle of filaments, the A2 bundle of filaments, the B1 bundle of filaments and the B2 bundle of filaments when forming a knot is 40°.

6. The silicon carbide fiber splicing method according to claim 1, characterized by: In step S2, the positions of the A3 end and the B3 end are fixed by clamps installed on the silicon carbide fiber bundle A and the silicon carbide fiber bundle B.

7. The silicon carbide fiber splicing method according to claim 1, characterized by: The silicon carbide fiber bundle A and the silicon carbide fiber bundle B are prepared by using polycarbosilane precursor, and sequentially subjected to high-temperature pyrolytic synthesis, melt spinning, pre-oxidation treatment.

8. The silicon carbide fiber splicing method according to claim 1, characterized by: The silicon carbide fiber bundle A and the silicon carbide fiber bundle B are prepared by using polycarbosilane precursor, and sequentially subjected to high-temperature pyrolytic synthesis, melt spinning, pre-oxidation treatment, high-temperature sintering treatment.

9. The silicon carbide fiber splicing method according to claim 8, characterized by: The silicon carbide fiber bundle A and the silicon carbide fiber bundle B are prepared by using polycarbosilane precursor, and sequentially subjected to high-temperature pyrolytic synthesis, melt spinning, pre-oxidation treatment, high-temperature sintering treatment, and a yarn winding drum.

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