阅读说明：本技术 一种SiC复合材料包壳管的端塞制备方法 (Preparation method of end plug of SiC composite material cladding tube ) 是由 卢永恒 冯海宁 郭洪 刘建成 田广丰 黄立功 孟莹 于 2020-12-31 设计创作，主要内容包括：本发明属于新型核包壳材料制造技术领域,具体涉及一种SiC复合材料包壳管的端塞制备方法。将SiC晶须按照总体积含量10％—30％与SiC粉末混合；将配比后的SiC晶须与SiC粉末放入三维混料罐中；将混合后的SiC晶须与SiC粉末放入石墨承压模具中；将石墨承压模具装入热压烧结炉中；热压烧结炉抽真空；通过上下冲头对石墨承压模具内的SiC晶须与SiC粉末加压；加热升温后保温,对石墨承压模具内的SiC晶须与SiC粉末进行烧结成型；保温结束后降至室温,去除石墨承压模具压力,去除热压烧结炉真空,取出石墨承压模具内烧结好的SiC复合材料包壳管的端塞。制备的SiC复合材料包壳管端塞相对密度达到96％以上,外形尺寸满足技术要求。(The invention belongs to the technical field of novel nuclear cladding material manufacturing, and particularly relates to a preparation method of an end plug of a SiC composite material cladding tube. Mixing the SiC whisker with SiC powder according to the total volume content of 10-30%; placing the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank; placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die; loading the graphite pressure-bearing die into a hot-pressing sintering furnace; vacuumizing the hot-pressing sintering furnace; pressurizing the SiC whiskers and the SiC powder in the graphite pressure-bearing die through an upper punch and a lower punch; heating and maintaining the temperature, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing mold; and cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing die, removing the vacuum of the hot-pressing sintering furnace, and taking out the end plugs of the SiC composite material cladding tube sintered in the graphite pressure-bearing die. The relative density of the prepared SiC composite material cladding tube end plug reaches over 96 percent, and the external dimension meets the technical requirement.)

1. A preparation method of an end plug of a SiC composite material cladding tube is characterized by comprising the following steps:

1) mixing the SiC whisker with SiC powder according to the total volume content of 10-30%;

2) placing the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank;

3) placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die;

4) loading the graphite pressure-bearing die into a hot-pressing sintering furnace;

5) vacuumizing the hot-pressing sintering furnace;

6) pressurizing the SiC whiskers and the SiC powder in the graphite pressure-bearing die through an upper punch and a lower punch;

7) heating and maintaining the temperature, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing mold;

8) and cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing die, removing the vacuum of the hot-pressing sintering furnace, and taking out the end plugs of the SiC composite material cladding tube sintered in the graphite pressure-bearing die.

2. The method of making an end plug for a SiC composite cladding tube of claim 1, wherein: the purity of the SiC whisker is more than 99 percent, and the length-diameter ratio is more than 15.

3. The method of making an end plug for a SiC composite cladding tube of claim 1, wherein: the purity of the SiC powder is more than 99 percent, and the granularity is 5-20 mu m.

4. The method of making an end plug for a SiC composite cladding tube of claim 1, wherein: and (3) putting the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank for mixing for 2-4 h.

5. The method of making an end plug for a SiC composite cladding tube of claim 1, wherein: the hot-pressing sintering furnace is vacuumized to 10^－1Keeping for 1-3 h after Pa.

6. The method of making an end plug for a SiC composite cladding tube of claim 1, wherein: pressurizing the SiC whiskers and the SiC powder in the die to 40-50 MPa by an upper punch and a lower punch.

7. The method of making an end plug for a SiC composite cladding tube of claim 1, wherein: heating to 1700 ℃, and then preserving heat for 2-4 h.

Technical Field

The invention belongs to the technical field of novel nuclear cladding material manufacturing, and particularly relates to a preparation method of an end plug of a SiC composite material cladding tube.

Background

The SiC ceramic has the advantages of excellent high-temperature performance, high hardness, corrosion resistance, low chemical activity, low specific gravity and the like, and is widely concerned in the field of high-temperature structural materials. Continuous silicon carbide fiber reinforced silicon carbide (SiC)_fthe/SiC) composite material has pseudo-plastic fracture behavior, low absorptivity to thermal neutrons and radiation resistance, provides possibility for application of the composite material in the field of nuclear fuel elements, and becomes a fourth-generation nuclear reactor cladding material with great potential. The SiC/SiC fuel cladding has the following advantages over zirconium alloy cladding: (1) SiC has low reactivity with water, and cannot explode even if loss of coolant accident (LOCA) is met; (2) the SiC has lower absorptivity to thermal neutrons, which is about 25% lower than that of a zirconium cladding with the same wall thickness, and the fuel is saved; (3) the melting point is high (2730 ℃), the reactor cannot be melted down, the operating temperature of the reactor can be increased, the power is increased, the nuclear fuel is more sufficiently combusted, and the difficulty in waste treatment is greatly reduced; (4) the high-temperature strength and the corrosion resistance are excellent, the service cycle of the cladding tube can be greatly prolonged, and the service life of the cladding tube is even the same as that of fuel. Therefore, the research on the preparation process of the SiC composite material cladding is significant for prolonging the service life of the fuel element, improving the fuel consumption and increasing the economic benefits of the operation of the reactor.

At present, traditional nuclear power strong countries such as America, Japan, France and the like develop research and development in the field, most of publicly reported information is concentrated on the aspect of manufacturing cladding tubes, and the preparation of end plugs of fuel cladding tubes is still in the stage of exploration and research.

Disclosure of Invention

The invention aims to provide a method for preparing an end plug of a SiC composite material cladding tube, which provides conditions for preparing a full-specification SiC composite material cladding tube.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for preparing an end plug of a SiC composite material cladding tube,

1) mixing the SiC whisker with SiC powder according to the total volume content of 10-30%;

2) placing the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank;

3) placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die;

4) loading the graphite pressure-bearing die into a hot-pressing sintering furnace;

5) vacuumizing the hot-pressing sintering furnace;

6) pressurizing the SiC whiskers and the SiC powder in the graphite pressure-bearing die through an upper punch and a lower punch;

7) heating and maintaining the temperature, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing mold;

8) and cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing die, removing the vacuum of the hot-pressing sintering furnace, and taking out the end plugs of the SiC composite material cladding tube sintered in the graphite pressure-bearing die.

The purity of the SiC whisker is more than 99 percent, and the length-diameter ratio is more than 15.

The purity of the SiC powder is more than 99 percent, and the granularity is 5-20 mu m.

And (3) putting the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank for mixing for 2-4 h.

The hot-pressing sintering furnace is vacuumized to 10^-1Keeping for 1-3 h after Pa.

Pressurizing the SiC whiskers and the SiC powder in the die to 40-50 MPa by an upper punch and a lower punch.

Heating to 1700 ℃, and then preserving heat for 2-4 h.

The beneficial effects obtained by the invention are as follows:

the structure and the component composition of the SiC composite material cladding tube end plug are designed for the first time, the process method and the process flow are designed, the process parameters are determined through process experiments, the relative density of the prepared SiC composite material cladding tube end plug reaches over 96 percent, the appearance size meets the technical requirements, and the technical basis and the guarantee are provided for the development and the application of a new generation of full-specification silicon carbide cladding material.

Detailed Description

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

And mixing the SiC whisker and SiC powder according to a certain proportion, filling the mixture into a pressure-bearing die, and obtaining the SiC whisker reinforced composite material end plug by a hot-pressing sintering mode at a certain temperature and pressure.

The technical scheme for realizing the purpose of the invention is as follows: preparation of an end plug of a SiC composite cladding tube, comprising the steps of:

1) SiC whiskers (purity > 99% and aspect ratio >15) are mixed with SiC powder (purity > 99% and particle size 5-20 μm) according to the total volume content of 10% -30%.

2) And (3) putting the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank, and mixing for 2-4 h.

3) And placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die.

4) And (3) putting the graphite pressure-bearing die into a hot-pressing sintering furnace.

5) The hot-pressing sintering furnace is vacuumized to 10^-1Keeping for 1-3 h after Pa.

6) Pressurizing the SiC whiskers and the SiC powder in the die to 40-50 MPa by an upper punch and a lower punch.

7) Heating to 1700 ℃, then preserving heat for 2-4 h, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing die.

8) And cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing mold, removing the vacuum of the hot pressing furnace, and taking out the end plug of the SiC composite material cladding tube sintered in the graphite pressure-bearing mold.

Example 1

The invention relates to a preparation method of an end plug of a SiC composite material cladding tube, which comprises the following steps:

1) SiC whiskers (purity > 99% and aspect ratio >15) are mixed with SiC powder (purity > 99% and particle size 5-20 μm) according to a volume content of 15% by volume.

2) And (3) putting the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank, and mixing for 2 h.

3) And placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die.

4) And (3) putting the graphite pressure-bearing die into a hot-pressing sintering furnace.

5) The hot-pressing sintering furnace is vacuumized to 10^-1After Pa, the time is kept for 1.5 h.

6) And pressurizing the SiC whiskers and the SiC powder in the die to 40MPa through an upper punch and a lower punch.

7) And heating to 1700 ℃, preserving heat for 2h, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing die.

8) And cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing mold, removing the vacuum of the hot pressing furnace, and taking out the end plug of the SiC composite material cladding tube sintered in the graphite pressure-bearing mold.

Example 2

The invention relates to a preparation method of an end plug of a SiC composite material cladding tube, which comprises the following steps:

1) SiC whiskers (purity > 99% and aspect ratio >15) are mixed with SiC powder (purity > 99% and particle size 5-20 μm) according to a total volume content of 20%.

2) And (3) putting the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank, and mixing for 3 hours.

3) And placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die.

4) And (3) putting the graphite pressure-bearing die into a hot-pressing sintering furnace.

5) The hot-pressing sintering furnace is vacuumized to 10^-1After Pa, the pressure was maintained for 2 h.

6) Pressurizing the SiC whiskers and the SiC powder in the die to 45MPa through an upper punch and a lower punch.

7) And heating to 1700 ℃, preserving heat for 3h, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing die.

8) And cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing mold, removing the vacuum of the hot pressing furnace, and taking out the end plug of the SiC composite material cladding tube sintered in the graphite pressure-bearing mold.

Example 3

The invention relates to a preparation method of an end plug of a SiC composite material cladding tube, which comprises the following steps:

1) SiC whiskers (purity > 99% and aspect ratio >15) are mixed with SiC powder (purity > 99% and particle size 5-20 μm) according to a total volume content of 25%.

2) And (3) putting the proportioned SiC whiskers and SiC powder into a three-dimensional mixing tank, and mixing for 4 hours.

3) And placing the mixed SiC whiskers and SiC powder into a graphite pressure-bearing die.

4) And (3) putting the graphite pressure-bearing die into a hot-pressing sintering furnace.

5) The hot-pressing sintering furnace is vacuumized to 10^-1After Pa, the time is kept for 2.5 h.

6) Pressurizing the SiC whiskers and the SiC powder in the die to 50MPa through an upper punch and a lower punch.

7) Heating to 1700 ℃, preserving heat for 4h, and sintering and molding the SiC whiskers and the SiC powder in the graphite pressure-bearing die.

8) And cooling to room temperature after heat preservation is finished, removing the pressure of the graphite pressure-bearing mold, removing the vacuum of the hot pressing furnace, and taking out the end plug of the SiC composite material cladding tube sintered in the graphite pressure-bearing mold.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned examples, and various schemes which are not substantially different from the concept of the present invention are within the protection scope of the present invention.