阅读说明：本技术 一种制备陶瓷纤维预制体专用针刺及其使用方法 (Special needling for preparing ceramic fiber preform and use method thereof ) 是由 张涛 吴来军 于海静 温广武 黄小萧 钟博 夏龙 于 2019-10-29 设计创作，主要内容包括：一种制备陶瓷纤维预制体专用针刺及其使用方法,涉及陶瓷纤维预制体领域,针刺的结构为：设有针刺主体,针刺主体上设有气流腔,气流腔上设有在针刺主体上随机分布的气体射流孔,气体射流孔的直径为0.08mm-0.2mm,气体射流孔密度为35-60个/cm<Sup>2</Sup>,气体射流孔与针刺主体的轴线夹角在10°-75°。使用方法为：短切陶瓷纤维长纱线、制成网胎,网胎与陶瓷纤维单向布植绒复合,得的复合坯料；至少2层的复合坯料重叠后使用安装上述专用针刺的针刺机复合针刺,专用针刺的气流腔连接气源、输入压缩空气。本发明具有加工成本低廉、生产效率高,对纤维损伤小、层间不易分离,制备的陶瓷纤维预制体的力学性能优等优点。(A special needling for preparing a ceramic fiber preform and a using method thereof relate to the field of ceramic fiber preforms, and the structure of the needling is as follows: is provided with a needling main body, an airflow cavity is arranged on the needling main body, gas jet holes which are randomly distributed on the needling main body are arranged on the airflow cavity, the diameter of the gas jet holes is 0.08mm-0.2mm, and the density of the gas jet holes is 35-60/cm 2 The included angle between the gas jet hole and the axis of the acupuncture main body is 10-75 degrees. The using method comprises the following steps: short-cut ceramic fiber long yarns are made into a net body, and the net body and the ceramic fibers are compounded by unidirectional implanted velvet to obtain a composite blank; and (3) after the composite blanks with at least 2 layers are overlapped, carrying out composite needling by using a needling machine provided with the special needling, wherein an airflow cavity of the special needling is connected with an air source and compressed air is input. The invention has the advantages of low processing cost, high production efficiency, small damage to fibers, difficult interlayer separation, excellent mechanical property of the prepared ceramic fiber preform and the like.)

1. The special needling for the ceramic fiber preform is provided with a needling main body and is characterized in that the needling main body is provided with an air flow cavity which is coaxial with the needling main body and is communicated up and down, the side wall of the air flow cavity is provided with a gas jet hole, the diameter of the gas jet hole is 0.08mm-0.2mm, and the density of the gas jet hole is 35-60/cm²The gas jet holes are randomly distributed on the acupuncture main body; the included angle between the gas jet hole and the axis of the acupuncture main body is 10-75 degrees.

2. According to the claimsThe special needling for the ceramic fiber preform of claim 1 is characterized in that the diameter of the gas jet hole is 0.12 mm-0.16 mm, and the density of the gas jet hole is 45-50/cm²The included angle between the gas jet hole and the axis of the acupuncture main body is 20-60 degrees.

3. The special needling for the ceramic fiber preform according to claim 1, wherein the needling main body is composed of a cylindrical connecting section at the upper part and a conical needling section at the lower part; the shape of the airflow cavity is the same as that of the acupuncture main body; the gas jet hole is positioned in the needling section.

4. The use method of special needling of ceramic fiber preforms according to claim 1, characterized in that it comprises the following steps:

(1) short-cutting the ceramic fiber long yarn into short fibers with the length of 80-150 mm;

(2) dispersing the chopped fiber by a dry method to prepare the chopped fiber with the gram weight of 15-80g/m²The whole process of the net tire does not add a softener and any other liquid solvent;

(3) mixing the net tyre with 80-420g/m²The ceramic fiber unidirectional cloth or the 2D woven cloth is flocked and compounded to obtain 95 to 500g/m²The composite blank of (1);

(4) overlapping at least 2 layers of composite blanks, and performing composite needling by using a needling machine to thicken and densify; the needle plate of the needle machine is provided with the special needle for the ceramic fiber prefabricated body, and the special needle density of the ceramic fiber prefabricated body on the needle plate is 10-35 pieces/cm²Connecting the air flow cavity special for ceramic fiber preform needling with an air source, and inputting compressed air with the pressure of 0.4-0.8MPa into the air flow cavity special for ceramic fiber preform needling.

5. The method as claimed in claim 4, wherein the reciprocating frequency of the needle plate is 100-190 times/min.

6. The method for using special needling of ceramic fiber preforms as claimed in claim 4, wherein the feeding speed of the composite needling of the overlapped composite blanks on a needling machine is 10-20 mm/s.

7. The use method of special needling for ceramic fiber preforms as claimed in claim 4, characterized in that the special needling for ceramic fiber preforms is 1-10 cm in the longitudinal direction of the needle board²The upper and the transverse directions are uniformly distributed in the range not less than the width of the composite blank.

Technical Field

The invention relates to the field of ceramic fiber preforms, in particular to special needling for preparing a ceramic fiber preform and a using method thereof, wherein the special needling is low in processing cost, high in production efficiency, small in fiber damage, not easy to separate layers and excellent in mechanical property of the prepared ceramic fiber preform.

Background

As is known, the ceramic fibers are SiO₂The high-performance fiber with the heat resistance, the corrosion resistance and the weaving characteristic has the mass fraction content of more than 99.9 percent. High strength retention rate at high temperature, low thermal expansion coefficient, thermal shock resistance, chemical stability, light transmittance and electric insulation. In addition, the material has incomparably low dielectric constant and is an ideal wave-transmitting material. The long-term service temperature of the ceramic fiber can reach 1200 ℃, and the softening point temperature can reach 1700 ℃. Therefore, the ceramic fiber has important application in military, national defense, aviation and aerospace industries, and can be used for manufacturing rocket fire nozzles, aerospace thermal protection devices, antenna cover windows and the like.

In view of the above indispensable effects, the production amount of ceramic fiber preforms is also expanding and quality is also sought to be excellent. One key link in producing high-quality quartz composite material is the selection of ceramic fiber preform. The quality of the ceramic fiber preform is the key to controlling the cost and quality of the quartz composite material. At present, the common methods include carding, web forming and superimposed needling, or scattering short quartz fibers into a solvent, carrying out suction filtration forming, then drying and sintering. Due to the carding, web forming and overlapping needling processes, the damage to the ceramic fiber monofilament is large, and the interlayer bonding force is low, usually 0.1-0.2N/cm²And the layers are easy to separate. The mechanical property of the quartz composite material prepared subsequently is obviously reduced. The dispersion and suction filtration molding process of the quartz short fibers needs a large amount of solvent, has obvious influence on the environment, and forms a large amount of absorption hydroxyl on the surfaces of the fibers, so the process has high cost, the prepared composite material has poor mechanical property, and the sintering environment is polluted.

Disclosure of Invention

The invention aims to solve the defects of the prior art and provides the special needling for preparing the ceramic fiber preform and the use method thereof, wherein the special needling is low in processing cost, high in production efficiency, small in fiber damage, not easy to separate layers and excellent in mechanical property of the prepared ceramic fiber preform.

The special needling for the ceramic fiber preform is provided with a needling main body and is characterized in that the needling main body is provided with an air flow cavity which is coaxial with the needling main body and is communicated up and down, the side wall of the air flow cavity is provided with a gas jet hole, the diameter of the gas jet hole is 0.08mm-0.2mm, and the density of the gas jet hole is 35-60/cm²The gas jet holes are randomly distributed on the acupuncture main body; the included angle between the gas jet hole (gas flow direction) and the axis of the acupuncture main body is 10-75 degrees.

Preferably, the diameter of the gas jet hole is 0.12 mm-0.16 mm, and the density of the gas jet hole is 45-50/cm²The included angle between the gas jet hole and the axis of the acupuncture main body is 20-60 degrees.

The acupuncture main body consists of a cylindrical connecting section at the upper part and a conical acupuncture section at the lower part; the shape of the airflow cavity is the same as that of the acupuncture main body; the gas jet hole is positioned in the needling section.

A use method of special needling for a ceramic fiber preform is characterized by comprising the following steps:

(1) cutting the ceramic fiber long yarn (A type or B type, 20-1000 tex) into chopped fiber with the length of 80-150 mm;

(2) dispersing the chopped fiber by a dry method to prepare the chopped fiber with the gram weight of 15-80g/m²The whole process of the net tire does not add a softener and any other liquid solvent;

(3) mixing the net tyre with 80-420g/m²The ceramic fiber unidirectional cloth or the 2D woven cloth is flocked and compounded to obtain 95 to 500g/m²The composite blank of (1);

(4) overlapping at least 2 layers of composite blanks, and performing composite needling by using a needling machine to thicken and densify; the needle plate of the needle machine is provided with the special needle for the ceramic fiber prefabricated body, and the special needle density of the ceramic fiber prefabricated body on the needle plate is 10-35 pieces/cm²Air flow cavity special for needling ceramic fiber preformConnecting an air source, and inputting compressed air with the pressure of 0.4-0.8MPa into the air flow cavity special for needling of the ceramic fiber preform.

When the needle machine works, the reciprocating frequency of the needle plate is 100-190 times/min.

The feeding speed of the composite needling of the overlapped composite blank on the needling machine is 10-20 mm/s.

The special needling of the ceramic fiber preform is carried out in the longitudinal direction of the needle plate by 1-10 cm²The upper and the transverse directions are uniformly distributed in the range not less than the width of the composite blank.

The density of the ceramic fiber preform prepared by the method is 0.5-0.88g/cm³5-120mm thick, 30-45% of fiber content (in total fiber content) in Z direction and other directions (non-XY direction), and interlayer bonding force>0.4N/cm². The invention has small damage to the ceramic fiber monofilament, large interlayer binding force and difficult separation, and the prepared quartz composite material has good mechanical property. The method has the advantages of low processing cost, high efficiency, small damage to fibers, capability of reducing the manufacturing cost of the quartz composite material, improvement on the mechanical property of the quartz composite material and the like.

Drawings

FIG. 1 is a schematic structural view of a special needling of a ceramic fiber preform according to the present invention.

Detailed Description

A special needling for ceramic fiber preforms is provided with a needling main body, wherein the needling main body consists of a cylindrical connecting section 1 at the upper part and a conical needling section 3 at the lower part; the acupuncture main body is provided with an air flow cavity 4 which is coaxial with the acupuncture main body and is communicated up and down, and the shape of the air flow cavity 4 is the same as that of the acupuncture main body and consists of a cylindrical cavity section at the upper part and a conical cavity section at the lower part. The side wall (acupuncture main body) of the airflow cavity 4 is provided with a gas jet hole 2, and the gas jet hole 2 is positioned on the side wall of the airflow cavity of the acupuncture section. The diameter of the gas jet hole 2 is 0.08mm-0.2mm, and the density of the gas jet hole 2 is 35-60/cm²The positions of the gas jet holes on the acupuncture main body (around the acupuncture section) are randomly distributed, and the included angle between the gas jet holes and the axis of the acupuncture main body is 10-75 degrees.