阅读说明：本技术 变密度c/c复合材料喉衬的制备方法 (Preparation method of variable-density C/C composite throat insert ) 是由 陈海昆 高银东 艾余前 任海成 吴广力 于 2020-12-31 设计创作，主要内容包括：本发明涉及C/C复合陶瓷技术领域,公开了一种变密度C/C复合材料喉衬的制备方法,包括如下步骤：将碳纤维布和碳毡依次铺叠,通过针刺方式制备设有密度梯度的喉衬预制体,然后置于化学气相沉积炉内,进行化学气相沉积,再置于真空浸渍罐内,在真空环境下,使用糠酮树脂浸渍,完成后放入烘箱中固化,然后置于碳化炉内,抽真空,升温进行基体碳化,重复固化和碳化至喉衬预制体密度达到1.8～1.9g/cm～3后,进行高温处理,将取得的喉衬预制体,通过机械加工将坯料加工至喉衬要求尺寸,完成喉衬制备。本发明变密度C/C复合材料喉衬的制备方法,在保证喉衬强度及耐高温烧蚀性能前提下,有效缩短制备周期,降低制备成本。(The invention relates to the technical field of C/C composite ceramics, and discloses a preparation method of a variable-density C/C composite throat insert, which comprises the following steps: sequentially laying carbon fiber cloth and carbon felt, preparing a throat lining preform with a density gradient in a needling mode, then placing the throat lining preform in a chemical vapor deposition furnace for chemical vapor deposition, then placing the throat lining preform in a vacuum impregnation tank, impregnating the throat lining preform with furfuryl ketone resin in a vacuum environment, curing the throat lining preform in an oven after the throat lining preform is finished, then placing the throat lining preform in a carbonization furnace, vacuumizing the carbonization furnace, heating the throat lining preform to carbonize a matrix, and repeating the curing and the carbonization until the density of the throat lining preform reaches 1.8-1.9 g/cm 3 And then, carrying out high-temperature treatment, and machining the blank of the obtained throat insert preform to the required size of the throat insert through mechanical machining to finish the preparation of the throat insert. The preparation method of the variable-density C/C composite throat insert effectively shortens the preparation period and reduces the preparation cost on the premise of ensuring the strength and the high-temperature ablation resistance of the throat insert.)

1. A method for preparing a throat insert made of variable-density C/C composite material is characterized by comprising the following steps: the method comprises the following steps:

A) sequentially laying carbon fiber cloth (1) and carbon felt (2), and preparing a throat lining preform with a density gradient in a needling manner, wherein the density is 0.45-0.55 g/cm³；

B) Placing the throat lining preform prepared in the step A) into a chemical vapor deposition furnace, heating to 900-1100 ℃, introducing mixed gas of methane and nitrogen for chemical vapor deposition until the density of the throat lining preform reaches 1.4-1.6 g/cm³；

C) Placing the throat lining preform treated in the step B) in a vacuum impregnation tank, impregnating the throat lining preform with furfuryl ketone resin in a vacuum environment, and then placing the throat lining preform in an oven for curing;

D) placing the throat insert preform processed in the step C) in a carbonization furnace, vacuumizing, and heating to perform matrix carbonization;

E) repeating the step C) and the step D) until the density of the throat insert preform reaches 1.8-1.9 g/cm³Then, carrying out high-temperature treatment;

F) and F) machining the blank of the throat insert preform obtained in the step F) to the required size of the throat insert through machining, and thus finishing the preparation of the throat insert.

2. The method for preparing the variable-density C/C composite throat insert according to claim 1, wherein the method comprises the following steps: in the step A), the carbon fiber cloth (1) is laid alternately in a 0 degree/90 degree lay direction and is a non-woven cloth.

3. The method for preparing the variable-density C/C composite throat insert according to claim 1, wherein the method comprises the following steps: the inner wall of the middle part of the throat lining preform prepared in the step A) is a high-temperature ablation surface (3), the part of the throat lining preform, which is close to the high-temperature ablation surface (3), is a high-density area (4), and the part, which is far away from the high-temperature ablation surface (3), is a low-density area (5).

4. The method for preparing the variable-density C/C composite throat insert according to claim 1, wherein the method comprises the following steps: in the step B), the ratio of methane to nitrogen is 1: 1-2, and the flow of the mixed gas is 5-20 mL/min in the deposition process.

5. The method for preparing the variable-density C/C composite throat insert according to claim 1, wherein the method comprises the following steps: in the step C), the dipping vacuum degree is-0.06-0.09 MPa, the dipping time is 3-5 h, the curing temperature is 150-200 ℃, and the curing time is 5-8 h.

6. The method for preparing the variable-density C/C composite throat insert according to claim 1, wherein the method comprises the following steps: in the step D), the vacuum degree is-0.06 to-0.09 MPa, the carbonization temperature is 850 to 950 ℃, and the carbonization time is 30 to 40 hours.

7. The method for preparing the variable-density C/C composite throat insert according to claim 1, wherein the method comprises the following steps: in the step E), the high-temperature treatment temperature is 1800-2600 ℃, and the high-temperature treatment time is 10-20 hours.

Technical Field

The invention relates to the technical field of C/C composite ceramics, in particular to a preparation method of a throat insert made of variable-density C/C composite materials.

Background

The C/C composite material is a porous material taking a carbon fiber braided body as a reinforcement and graphite as a matrix, has excellent performances of low density, low thermal expansion coefficient, ablation resistance and the like, and is the most common material for the throat insert of the solid rocket engine at present.

However, in the prior art, the C/C composite material is mainly prepared by a liquid-phase impregnation carbonization method, a chemical vapor deposition (CVI) method and a combination method thereof, and has the problems of long preparation period and high preparation cost.

Disclosure of Invention

The invention aims to provide a method for preparing a throat insert made of variable-density C/C composite material aiming at the defects of the technology, so that the preparation period is effectively shortened and the preparation cost is reduced on the premise of ensuring the strength and the high-temperature ablation resistance of the throat insert.

In order to achieve the aim, the invention designs a preparation method of a variable density C/C composite throat insert, which comprises the following steps:

A) sequentially laying carbon fiber cloth and carbon felt, and preparing a throat lining preform with a density gradient in a needling manner, wherein the density is 0.45-0.55 g/cm³；

B) Placing the throat lining preform prepared in the step A) into a chemical vapor deposition furnace, heating to 900-1100 ℃, introducing mixed gas of methane and nitrogen for chemical vapor deposition until the density of the throat lining preform reaches 1.4-1.6 g/cm³；

C) Placing the throat lining preform treated in the step B) in a vacuum impregnation tank, impregnating the throat lining preform with furfuryl ketone resin in a vacuum environment, and then placing the throat lining preform in an oven for curing;

D) placing the throat insert preform processed in the step C) in a carbonization furnace, vacuumizing, and heating to perform matrix carbonization;

E) repeating said steps C) and D)Until the density of the throat lining preform reaches 1.8-1.9 g/cm³Then, carrying out high-temperature treatment;

F) and F) machining the blank of the throat insert preform obtained in the step F) to the required size of the throat insert through machining, and thus finishing the preparation of the throat insert.

Preferably, in the step a), the carbon fiber cloth is a non-woven cloth, and the carbon fiber cloth is alternately laid in the laying direction of 0 °/90 °.

Preferably, the inner wall of the middle part of the throat insert preform prepared in the step A) is a high-temperature ablation surface, the part of the throat insert preform close to the high-temperature ablation surface is a high-density area, and the part far away from the high-temperature ablation surface is a low-density area.

Preferably, in step B), the ratio of methane to nitrogen is 1: 1-2, and the flow of the mixed gas is 5-20 mL/min in the deposition process.

Preferably, in the step C), the dipping vacuum degree is-0.06 to-0.09 MPa, the dipping time is 3 to 5 hours, the curing temperature is 150 to 200 ℃, and the curing time is 5 to 8 hours.

Preferably, in the step D), the vacuum degree is-0.06 to-0.09 MPa, the carbonization temperature is 850 to 950 ℃, and the carbonization time is 30 to 40 hours.

Preferably, in the step E), the high-temperature treatment temperature is 1800-2600 ℃, and the high-temperature treatment time is 10-20 hours.

Compared with the prior art, the invention has the following advantages:

1. on the premise of ensuring the strength and high-temperature ablation resistance of the throat liner, the preparation period is effectively shortened, and the preparation cost is reduced;

2. because the fabric has density gradient, the low density area is more beneficial to gas permeation, the chemical vapor deposition time is shortened, the deposition efficiency is improved, the density difference of the high density area is reduced, and the ablation resistance of the high density area is improved;

3. on the premise of ensuring the compact ablation surface, the non-ablation density is reduced, the weight of the throat insert is reduced, and the efficiency of the engine is improved.

Drawings

FIG. 1 is a schematic structural diagram of a throat insert preform in the method for preparing a variable density C/C composite throat insert of the present invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a schematic diagram of the laying of carbon fiber cloth and carbon felt in the method for preparing the throat insert of the variable density C/C composite material.

The components in the figures are numbered as follows:

the carbon fiber cloth comprises carbon fiber cloth 1, a carbon felt 2, a high-temperature ablation surface 3, a high-density area 4 and a low-density area 5.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example one

A method for preparing a variable-density C/C composite throat insert comprises the following steps:

A) as shown in figures 1, 2 and 3, carbon fiber cloth 1 and carbon felt 2 are sequentially laid, and a throat lining preform with a density gradient of 0.45g/cm is prepared by a needle punching method³The carbon fiber cloth 1 is laid alternately in a laid direction of 0 DEG/90 DEG, the inner wall of the middle part of the throat lining prefabricated part is a high-temperature ablation surface 3, the part of the throat lining prefabricated part, which is close to the high-temperature ablation surface 3, is a high-density area 4, and the part, which is far away from the high-temperature ablation surface 3, is a low-density area 5;

B) placing the throat lining preform prepared in the step A) into a chemical vapor deposition furnace, heating to 900 ℃, introducing mixed gas of methane and nitrogen for chemical vapor deposition until the density of the throat lining preform reaches 1.4g/cm³Wherein the ratio of methane to nitrogen is 1: 1, introducing mixed gas into the reactor at a flow rate of 5mL/min in the deposition process;

C) placing the throat lining preform treated in the step B) in a vacuum impregnation tank, impregnating the throat lining preform by using furfuryl ketone resin in a vacuum environment, and then placing the throat lining preform in an oven for curing, wherein the impregnation vacuum degree is-0.06 MPa, the impregnation time is 3h, the curing temperature is 150 ℃, and the curing time is 5 h;

D) placing the throat insert preform processed in the step C) in a carbonization furnace, vacuumizing, heating to perform matrix carbonization, wherein the vacuum degree is-0.06 MPa, the carbonization temperature is 850 ℃, and the carbonization time is 30 hours;

E) repeating the step C) and the step D) until the density of the throat insert preform reaches 1.8g/cm³Then, high-temperature treatment is carried out, wherein the high-temperature treatment temperature is 1800 ℃, and the high-temperature treatment time is 10 hours;

F) and F) machining the blank of the throat insert preform obtained in the step F) to the required size of the throat insert through machining, and thus finishing the preparation of the throat insert.

Example two

A method for preparing a variable-density C/C composite throat insert comprises the following steps:

A) sequentially laying carbon fiber cloth 1 and carbon felt 2, and preparing a throat lining preform with a density gradient in a needling manner, wherein the density is 0.55g/cm³The carbon fiber cloth 1 is laid alternately in a laid direction of 0 DEG/90 DEG, the inner wall of the middle part of the throat lining prefabricated part is a high-temperature ablation surface 3, the part of the throat lining prefabricated part, which is close to the high-temperature ablation surface 3, is a high-density area 4, and the part, which is far away from the high-temperature ablation surface 3, is a low-density area 5;

B) placing the throat lining preform prepared in the step A) into a chemical vapor deposition furnace, heating to 1100 ℃, introducing mixed gas of methane and nitrogen for chemical vapor deposition until the density of the throat lining preform reaches 1.6g/cm³Wherein the ratio of methane to nitrogen is 1: 2, introducing mixed gas into the reactor at a flow rate of 20mL/min in the deposition process;

C) placing the throat lining preform processed in the step B) into a vacuum impregnation tank, impregnating the throat lining preform by using furfuryl ketone resin in a vacuum environment, and then placing the throat lining preform into an oven for curing, wherein the impregnation vacuum degree is-0.09 MPa, the impregnation time is 5 hours, the curing temperature is 200 ℃, and the curing time is 8 hours;

D) placing the throat insert preform processed in the step C) into a carbonization furnace, vacuumizing, heating to perform matrix carbonization, wherein the vacuum degree is-0.09 MPa, the carbonization temperature is 950 ℃, and the carbonization time is 40 h;

E) repeating the step C) and the step D) until the density of the throat insert preform reaches 1.9g/cm³Then, proceed withHigh-temperature treatment, wherein the high-temperature treatment temperature is 2600 ℃, and the high-temperature treatment time is 20 hours;

F) and F) machining the blank of the throat insert preform obtained in the step F) to the required size of the throat insert through machining, and thus finishing the preparation of the throat insert.

EXAMPLE III

A method for preparing a variable-density C/C composite throat insert comprises the following steps:

A) sequentially laying carbon fiber cloth 1 and carbon felt 2, and preparing a throat lining preform with a density gradient in a needling manner, wherein the density is 0.50g/cm³The carbon fiber cloth 1 is laid alternately in a laid direction of 0 DEG/90 DEG, the inner wall of the middle part of the throat lining prefabricated part is a high-temperature ablation surface 3, the part of the throat lining prefabricated part, which is close to the high-temperature ablation surface 3, is a high-density area 4, and the part, which is far away from the high-temperature ablation surface 3, is a low-density area 5;

B) placing the throat lining preform prepared in the step A) into a chemical vapor deposition furnace, heating to 1000 ℃, introducing mixed gas of methane and nitrogen for chemical vapor deposition until the density of the throat lining preform reaches 1.5g/cm³Wherein the ratio of methane to nitrogen is 1: 1.5, introducing mixed gas with the flow rate of 10mL/min in the deposition process;

C) placing the throat lining preform treated in the step B) in a vacuum impregnation tank, impregnating the throat lining preform by using furfuryl ketone resin in a vacuum environment, and then placing the throat lining preform in an oven for curing, wherein the impregnation vacuum degree is-0.07 MPa, the impregnation time is 5h, the curing temperature is 175 ℃, and the curing time is 7 h;

D) placing the throat insert preform processed in the step C) in a carbonization furnace, vacuumizing, heating to perform matrix carbonization, wherein the vacuum degree is-0.07 MPa, the carbonization temperature is 900 ℃, and the carbonization time is 35 hours;

E) repeating the step C) and the step D) until the density of the throat insert preform reaches 1.85g/cm³Then, carrying out high-temperature treatment at 2200 ℃ for 15 h;

F) and F) machining the blank of the throat insert preform obtained in the step F) to the required size of the throat insert through machining, and thus finishing the preparation of the throat insert.

The preparation tests of the first embodiment, the second embodiment and the third embodiment are carried out by the tool, and the test data are as follows:

as shown in the above table, the density was 1.85g/cm, which is about 130 days, compared with the conventional preparation method³The ablation rate is 0.042mm/s, and the first to third embodiments effectively reduce the product density and shorten the preparation period under the condition of ensuring the ablation rate

The preparation method of the variable-density C/C composite throat insert effectively shortens the preparation period and reduces the preparation cost on the premise of ensuring the strength and the high-temperature ablation resistance of the throat insert; because the fabric has density gradient, the low density area is more beneficial to gas permeation, the chemical vapor deposition time is shortened, the deposition efficiency is improved, the density difference of the high density area is reduced, and the ablation resistance of the high density area is improved; on the premise of ensuring the compact ablation surface, the non-ablation density is reduced, the weight of the throat insert is reduced, and the efficiency of the engine is improved.