阅读说明：本技术 一种纤维增强二氧化硅陶瓷复合材料成型方法 (Method for forming fiber-reinforced silicon dioxide ceramic composite material ) 是由 慈吉良 刘一畅 张剑 吕毅 张昊 赵英民 于 2021-09-13 设计创作，主要内容包括：本发明公开一种纤维增强二氧化硅陶瓷复合材料成型方法,涉及纤维增强二氧化硅陶瓷复合材料技术领域,本发明利用真空浸渍-干燥一体成型装置,并通过纤维预制体预处理、合模、浸渍-干燥、脱模、热处理等步骤,能够一次快速成型纤维增强二氧化硅陶瓷复合材料,省去了多次合模、脱模过程,减少人为操作对复合材料均匀性的影响。(The invention discloses a forming method of a fiber reinforced silicon dioxide ceramic composite material, which relates to the technical field of fiber reinforced silicon dioxide ceramic composite materials.)

1. A method for forming a fiber reinforced silica ceramic composite material is characterized by comprising the following steps:

(1) placing the fiber preform in a muffle furnace for heating pretreatment to obtain the fiber preform without the impregnating compound, wherein the impregnating compound is residual in the process of manufacturing the fiber preform;

(2) placing the fiber preform without the impregnating compound in a tank body of a vacuum impregnation-drying integrated molding device, and removing air in the tank body;

(3) injecting silica sol or aluminum sol into the tank body, and keeping for a set time to repeatedly dip sol particles into the fiber preform; opening a material port of the tank body, discharging all sol in the tank body, setting a temperature control program, and heating the tank body to dry the fiber reinforced ceramic flat plate; repeating the step for multiple times to ensure that the fiber reinforced ceramic flat plate is uniformly densified;

(4) the tank body is disassembled, and the fiber reinforced ceramic flat plate which is uniformly densified is taken out to obtain a fiber reinforced ceramic composite material blank;

(5) and (3) placing the fiber reinforced ceramic composite material blank into a muffle furnace for sintering to finally obtain the fiber reinforced ceramic flat plate.

2. The method of claim 1, wherein the oxide fiber is woven in two dimensions or three dimensions to obtain a fiber preform, and the oxide fiber is one or more of alumina fiber, mullite fiber and mullite fiber.

3. The method of claim 1, wherein the temperature of the thermal pretreatment in step (1) is 50 to 600 ℃ and the thermal pretreatment time is 0.5 to 2 hours.

4. The method of claim 1, wherein the step (3) is performed for 2 to 24 hours to allow the sol particles to be repeatedly impregnated into the fiber preform.

5. The method as claimed in claim 1, wherein the drying temperature in step (3) is 120-200 ℃ and the drying time is 18-24 h.

6. The method of claim 1, wherein step (3) is repeated 6-12 times.

7. The method as claimed in claim 1, wherein the sintering temperature in step (5) is 600-1000 ℃ and the sintering time is 1-2 h.

8. The method as claimed in claim 7, wherein the sintering temperature in step (5) is preferably 700-.

9. The method of claim 1, wherein the vacuum impregnation-drying integrated molding apparatus comprises a tank, a heater, and a vacuum pump; the bottom of the tank body is provided with a material port, the top of the tank body is provided with an upper flange, the upper flange is provided with a valve, the tank body is used for storing the fiber preform or taking out the fiber reinforced ceramic composite material blank by opening the upper flange, and silica sol is input or output through the material port; the heater is connected with the tank body, and a heating program is set through a heating control panel of the heater to heat the tank body; the vacuum pump is connected with a valve of the flange on the tank body and is used for vacuumizing the tank body.

Technical Field

The invention relates to the technical field of fiber-reinforced silicon dioxide ceramic composite materials, in particular to a forming method of a fiber-reinforced silicon dioxide ceramic composite material.

Background

The fiber reinforced oxide ceramic matrix composite material has high temperature resistance, oxidation resistance, good mechanical strength and heat insulation performance, can replace metal materials with poor strength and toughness performance under high-temperature oxidation conditions and non-oxide-based ceramic composite materials, meets the application requirements of a new generation of aerospace craft and an aero-engine, and has wide application prospects in the fields of aviation, aerospace, nuclear energy and the like. At present, the preparation method of the fiber reinforced silicon dioxide ceramic generally adopts a vacuum impregnation-drying forming process. The method needs to weave continuous fibers into a three-dimensional fabric in advance, then carry out fabric pretreatment to remove a wetting agent, then carry out repeated impregnation-drying densification treatment, and finally carry out heat treatment to obtain the fiber reinforced silicon dioxide ceramic composite material. In the forming process, multiple mold closing and demolding are needed, the ceramic blank is taken out and placed in a vacuum oven for drying, and manpower and material resources are wasted; in addition, if the glue solution is not dried in time after being demolded, the glue solution can slowly flow out of the interior of the fabric under the action of gravity, so that density gradients are formed in different areas, and the performance of the composite material is affected.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a method for forming a fiber-reinforced silica ceramic composite material, which adopts continuous fibers as a reinforcing phase to reinforce the strength of a silica matrix, omits the processes of repeated mold closing and demolding and reduces the influence of manual operation on the uniformity of the composite material.

In order to solve the technical problems, the invention provides the following technical scheme:

a method for forming a fiber reinforced silica ceramic composite material comprises the following steps:

(1) pretreatment of the fiber preform: placing the fiber preform in a muffle furnace for heating pretreatment to obtain the fiber preform without the impregnating compound, wherein the impregnating compound is residual in the process of manufacturing the fiber preform;

(2) die assembly: placing the fiber preform without the impregnating compound in a tank body of a vacuum impregnation-drying integrated molding device, and removing air in the tank body;

(3) dipping and drying: injecting silica sol or aluminum sol into the tank body, and keeping for a set time to repeatedly dip sol particles into the fiber preform; opening a material port of the tank body, discharging all sol in the tank body, setting a temperature control program, and heating the tank body to dry the fiber reinforced ceramic flat plate; repeating the step for multiple times to ensure that the fiber reinforced ceramic flat plate is uniformly densified;

(4) demolding: the tank body is disassembled, and the fiber reinforced ceramic flat plate which is uniformly densified is taken out to obtain a fiber reinforced ceramic composite material blank;

(5) and (3) heat treatment: and (3) placing the fiber reinforced ceramic composite material blank into a muffle furnace for sintering to finally obtain the fiber reinforced ceramic flat plate.

Preferably, the oxide fiber is subjected to two-dimensional weaving or three-dimensional weaving to obtain a fiber preform, and the oxide fiber is one or more of alumina fiber, mullite fiber and quartz fiber.

Preferably, the temperature of the heating pretreatment in the step (1) is 50-600 ℃, and the heating pretreatment time is 0.5-2 h.

Preferably, the step (3) is maintained for 2-24h to allow the sol particles to be repeatedly impregnated into the fiber preform.

Preferably, the drying temperature in the step (3) is 120-200 ℃, and the drying time is 18-24 h.

Preferably, step (3) is repeated 6-12 times.

Preferably, the sintering temperature in the step (5) is 600-1000 ℃, and the sintering time is 1-2 h.

Preferably, the sintering temperature in step (5) is preferably 700-900 ℃.

Preferably, the vacuum impregnation-drying integrated molding device comprises a tank body, a heater and a vacuum pump; the bottom of the tank body is provided with a material port, the top of the tank body is provided with an upper flange, the upper flange is provided with a valve, the tank body is used for storing the fiber preform or taking out the fiber reinforced ceramic composite material blank by opening the upper flange, and silica sol is input or output through the material port; the heater is connected with the tank body, and a heating program is set through a heating control panel of the heater to heat the tank body; the vacuum pump is connected with a valve of the flange on the tank body and is used for vacuumizing the tank body.

The invention has the following advantages:

the fiber-reinforced silicon dioxide ceramic composite material provided by the invention is prepared by pretreating fibers to remove a sizing agent, then performing vacuum-drying for multiple times to obtain a compact ceramic blank, and finally performing heat treatment to obtain the composite material. The method saves the processes of repeated die assembly and demoulding, reduces the influence of manual operation on the uniformity of the composite material in the compounding process, improves the impregnation efficiency and saves the weaving cost. The preparation method provided by the invention has the advantages of simplicity, easiness in implementation, low cost, no pollution and the like.

Drawings

FIG. 1 is a flow chart of a method for forming a fiber reinforced silica ceramic composite.

Fig. 2 is a schematic view of a vacuum impregnation-drying integrated molding apparatus.

In the figure: 1-tank body, 2-heater, 3-vacuum pump, 4-upper flange, 5-valve and 6-material port.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention.

The invention provides a method for molding a fiber-reinforced silica ceramic composite material, which comprises the following steps as shown in figure 1:

(1) pretreatment of the fiber preform: and (2) carrying out two-dimensional weaving or three-dimensional weaving on the oxide fiber to obtain a fiber preform, wherein the oxide fiber is one or more of alumina fiber, mullite fiber and mullite fiber. Heating the fiber preform in a muffle furnace at 50-600 deg.C (any value in the range, such as 50 deg.C, 100 deg.C, 150 deg.C, 200 deg.C, 250 deg.C, 300 deg.C, 350 deg.C, 400 deg.C, 450 deg.C, 500 deg.C, 550 deg.C, 600 deg.C) for 0.5-2h (any value in the range, such as 0.5h, 1h, 1.5h, 2h) to obtain a fiber preform without the sizing agent, wherein the sizing agent is remained in the process of manufacturing the fiber preform;

(2) die assembly: placing the fiber preform without the impregnating compound in a tank body of a vacuum impregnation-drying integrated molding device, and starting a vacuum pump to remove air in the tank body;

(3) dipping and drying: injecting silica sol or aluminum sol into the tank, and keeping for 2-24h (any value in the range, such as 2h, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h and 24h) to repeatedly impregnate the sol particles into the fiber preform; opening a valve of the tank body, discharging all sol in the tank body, setting a temperature control program, heating the tank body to dry the fiber reinforced ceramic flat plate at the temperature of 120-; repeating the step 6-12 times (any value within the range, such as 6 times, 7 times, 8 times, 9 times, 10 times, 11 times, 12 times) to uniformly densify the fiber-reinforced ceramic slab;

(4) demolding: the tank body is disassembled, and the fiber reinforced ceramic flat plate which is uniformly densified is taken out to obtain a fiber reinforced ceramic composite material blank;

(5) and (3) heat treatment: and sintering the fiber reinforced ceramic composite material blank in a muffle furnace at the sintering temperature of 600-1000 ℃ (which can be any value in the range, such as 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, preferably 700-900 ℃), and for the sintering time of 1-2h (which can be any value in the range, such as 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h and 2h) to finally obtain the fiber reinforced ceramic flat plate.

The vacuum impregnation-drying integrated forming device used in the method comprises a tank body 1, a heater 2 and a vacuum pump 3; a material port 6 is arranged at the bottom of the tank body 1, an upper flange 4 is arranged at the top of the tank body, a valve 5 is arranged on the upper flange 4, the tank body 1 stores fiber preforms or takes out fiber reinforced ceramic composite material blanks by opening the upper flange 4, and sol is input or output through the material port 6; the heater 2 is connected with the tank body 1, and a heating program is set through a heating control panel of the heater to heat the tank body 1; the vacuum pump 3 is connected with a valve 5 of a flange 4 on the tank body 1 and is used for vacuumizing the tank body 1. The using process is as follows: (1) placing the fiber preform in the tank body 1, connecting the upper flange 4, connecting the valve 5 with the vacuum pump 3, and then starting the vacuum pump 3; (2) sucking and injecting the sol into the tank body 1 from a material port 6 at the bottom of the tank body 1, closing a valve 5 and the material port 6 of the tank body 1, and keeping for a certain time to ensure that the sol is soaked into the prefabricated body; (3) opening a material port 6 to enable the sol to flow out of the interior of the tank body 1, setting a temperature-raising program on a control panel of the heater 2, opening a switch of the heater 2, and heating an interlayer of the tank body 1 to enable the residual sol liquid in the internal prefabricated body to be dried and solidified; and heating for a certain time, naturally cooling to room temperature, opening the flange 4 on the tank body 1, taking out the prefabricated body to obtain an oxide fiber reinforced silicon dioxide ceramic blank, and sintering in a muffle furnace to obtain a final product.

Three examples are listed below:

example 1

S1, pretreatment of the fiber preform: and (3) placing the fiber preform in a muffle furnace, heating to 500 ℃ for pretreatment for 2h to obtain the fiber preform without the impregnating compound.

S2, mold closing: and (3) placing the fiber preform in a tank body of a vacuum impregnation-drying integrated forming device, connecting each part with the tank body, starting a vacuum pump, and removing air in the tank body.

S3, dipping and drying: injecting silica sol into a tank body, keeping the temperature for 20 hours, opening an upper valve and a lower valve of the tank body, completely discharging the sol in the tank body, setting a temperature control program, heating the tank body to 180 ℃ at a heating rate of 3 ℃/min, and preserving the temperature for 20 hours to dry the fiber reinforced ceramic flat plate blank.

S4, densification: the impregnation-drying process was repeated 8 times to achieve uniform densification of the fiber-reinforced ceramic slabs.

S5, demolding: the tank body is disassembled, and the flat plate is taken out, so that a fiber reinforced ceramic composite material blank is obtained;

s6, heat treatment: and placing the dried ceramic blank into a muffle furnace, and firing for 2 hours at 700 ℃ to finally obtain the fiber reinforced ceramic flat plate.

Example 2

S1, pretreatment of the fiber preform: and (3) placing the fiber preform in a muffle furnace, heating to 600 ℃ for pretreatment, wherein the pretreatment time is 0.5h, and obtaining the fiber preform without the impregnating compound.

S2, mold closing: and (3) placing the fiber preform in a drying tank body of a vacuum impregnation-drying integrated forming device, connecting each part with the tank body, starting a vacuum pump, and removing air in the tank body.

S3, dipping and drying: and (3) injecting the aluminum sol into the tank body, keeping the temperature for 24h, opening the upper valve and the lower valve of the tank body, completely discharging the sol in the tank body, setting a temperature control program, heating the tank body to 200 ℃ at a heating rate of 5 ℃/min, and preserving the heat for 18h to dry the fiber reinforced ceramic flat plate blank.

S4, densification: the impregnation-drying process was repeated 7 times to achieve uniform densification of the fiber-reinforced ceramic slabs.

S5, demolding: the tank body is disassembled, and the flat plate is taken out, so that a fiber reinforced ceramic composite material blank is obtained;

s6, heat treatment: and (3) placing the dried ceramic blank into a muffle furnace, and firing for 1h at 1000 ℃ to finally obtain the fiber reinforced silicon dioxide ceramic flat plate.

Example 3

S1, pretreatment of the fiber preform: and (3) placing the fiber preform in a muffle furnace, heating to 400 ℃ for pretreatment, wherein the pretreatment time is 1h, and obtaining the fiber preform without the impregnating compound.

S2, mold closing: and (3) placing the fiber preform in a tank body of a vacuum impregnation-drying integrated forming device, connecting each part with the tank body, starting a vacuum pump, and removing air in the tank body.

S3, dipping and drying: injecting silica sol into a tank body, keeping the temperature for 2 hours, opening an upper valve and a lower valve of the tank body, completely discharging the sol in the tank body, setting a temperature control program, heating the tank body to 120 ℃ at a heating rate of 3 ℃/min, and preserving the temperature for 24 hours to dry the fiber reinforced ceramic flat plate blank.

S4, densification: the impregnation-drying process was repeated 6 times to achieve uniform densification of the fiber-reinforced ceramic slabs.

S5, demolding: the tank body is disassembled, and the flat plate is taken out, so that a fiber reinforced ceramic composite material blank is obtained;

s6, heat treatment: and (3) placing the dried ceramic blank into a muffle furnace, and firing for 1.5h at the temperature of 600 ℃ to finally obtain the fiber reinforced ceramic flat plate.

One comparative example is listed below:

comparative example

S1, pretreatment of the fiber preform: and (3) placing the fiber preform in a muffle furnace, heating to 600 ℃ for pretreatment, wherein the pretreatment time is 1h, and obtaining the fiber preform without the impregnating compound.

S2, mold closing: and (3) placing the fiber preform in a vacuum impregnation-drying tank body, connecting each part with the tank body, starting a vacuum pump, and removing air in the tank body.

S3, dipping: injecting the alumina sol into a tank body of the vacuum impregnation-forming integrated device, and keeping for 20 hours;

s4, demolding and drying: the vacuum impregnation-molding integrated device is disassembled, and the flat plate is taken out to obtain a fiber reinforced ceramic composite material blank;

and S5, placing the obtained fiber reinforced ceramic composite material blank in a vacuum oven, heating the prefabricated body to 200 ℃ at the heating rate of 5 ℃/min, and preserving heat for 20h to dry the fiber reinforced ceramic flat plate blank.

S6, densification: the impregnation-drying process was repeated 8 times to achieve uniform densification of the fiber-reinforced ceramic slabs.

S7, heat treatment: and (3) placing the dried ceramic blank into a muffle furnace, and firing for 1h at 1000 ℃ to finally obtain the fiber reinforced silicon dioxide ceramic flat plate.

The method adopts a vacuum oven heating and drying mode, needs a plurality of die assembly and demolding procedures, needs 4-6 hours for single die assembly or demolding, needs 40-60 hours for 10 repeated dipping-drying processes, and greatly wastes operation time and manpower and material resources. The method of the invention adopts the vacuum-drying integrated forming device, can reduce the times of die assembly and demoulding, only needs one die assembly and demoulding process, and saves manpower and material resources.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and these modifications or substitutions do not make the essence of the corresponding technical solutions depart from the spirit and scope of the technical solutions of the embodiments of the present invention, and all other embodiments obtained by those skilled in the art without making creative efforts belong to the protection scope of the present invention.