阅读说明：本技术 短切碳化硅纤维增强ZrC多层包壳材料及其制备方法 (Chopped silicon carbide fiber reinforced ZrC multilayer cladding material and preparation method thereof ) 是由 吴事江 林杨 李拯 杨焕顺 张合军 于 2020-07-08 设计创作，主要内容包括：本发明涉及ZrC陶瓷材料技术领域,具体涉及一种短切碳化硅纤维增强ZrC多层包壳材料及其制备方法。所述的短切碳化硅纤维增强ZrC多层包壳材料的制备方法,先以骨料、短切SiC纤维、炭黑、热固性酚醛树脂为原料,并加入分散剂,通过混炼、注塑成型、低温固化、高温素烧得到多孔含碳预制体；再以锆或锆硅合金为熔渗剂,对多孔含碳预制体进行高温熔渗烧结,得到纤维增韧超高温陶瓷管；最后在陶瓷前驱体的乙醇溶液中提拉镀膜,并高温陶瓷转化,得到短切碳化硅纤维增强ZrC多层包壳材料。本发明的短切碳化硅纤维增强ZrC多层包壳材料,具有多层结构、高强度、高韧性；本发明的制备方法实现了包壳材料的高效率、等成本制备。(The invention relates to the technical field of ZrC ceramic materials, in particular to a chopped silicon carbide fiber reinforced ZrC multilayer cladding material and a preparation method thereof. The preparation method of the chopped silicon carbide fiber reinforced ZrC multilayer coating material comprises the steps of taking aggregate, chopped SiC fiber, carbon black and thermosetting phenolic resin as raw materials, adding a dispersing agent, and carrying out mixing, injection molding, low-temperature curing and high-temperature biscuiting to obtain a porous carbon-containing preform; then, zirconium or zirconium-silicon alloy is used as an infiltrant, and the porous carbon-containing prefabricated body is subjected to high-temperature infiltration sintering to obtain a fiber toughened ultrahigh-temperature ceramic tube; and finally, pulling the plated film in an ethanol solution of the ceramic precursor, and performing high-temperature ceramic conversion to obtain the chopped silicon carbide fiber reinforced ZrC multilayer cladding material. The chopped silicon carbide fiber reinforced ZrC multilayer cladding material has a multilayer structure, high strength and high toughness; the preparation method of the invention realizes the high-efficiency and equal-cost preparation of the cladding material.)

1. A preparation method of a chopped silicon carbide fiber reinforced ZrC multilayer cladding material is characterized by comprising the following steps: the method comprises the following steps:

(1) taking aggregate, chopped SiC fiber, carbon black and thermosetting phenolic resin as raw materials, adding a dispersing agent, and mixing, injection molding, low-temperature curing and high-temperature biscuiting to obtain a porous carbon-containing prefabricated body;

(2) carrying out high-temperature infiltration sintering on the porous carbon-containing prefabricated body by taking zirconium or zirconium-silicon alloy as an infiltration agent to obtain a fiber toughened ultrahigh-temperature ceramic tube;

(3) and taking an ethanol solution of a ceramic precursor as a sol, and carrying out lifting coating and high-temperature ceramic conversion on the fiber-toughened ultrahigh-temperature ceramic tube to obtain the chopped silicon carbide fiber-reinforced ZrC multilayer cladding material.

2. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (1), the raw materials in percentage by mass are:

the addition amount of the dispersing agent is 2-5% of the total mass of the aggregate, the chopped SiC fiber and the carbon black.

3. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (1), the aggregate is one or two of ZrC and SiC, and the particle size of D50 is 0.5-5.0 μm;

the length of the short-cut SiC fiber is 1-3 mm;

the thermosetting phenolic resin is one or more of barium phenolic resin, ammonia phenolic resin and boron phenolic resin;

the dispersant is polyacrylic acid.

4. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (1), the mixing process comprises the following steps: the open mill adopts a heating belt for heat preservation, the mixing temperature is 30-90 ℃, and the mixing time is 6-12 h;

the injection molding process comprises the following steps: the injection temperature is 50-120 ℃, the mould is made of graphite and is placed in a vacuum device, and the vacuum degree is 0.1-1 kPa.

5. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (1), the low-temperature curing process comprises the following steps: placing the injection molded biscuit and a mold in a vacuum furnace, wherein the vacuum degree is 0.1-1kPa, heating to 120 ℃ for 10-30min, and preserving heat for 1-2 h; heating to 160 ℃ for 10-60min, and keeping the temperature for 2 h; heating to 200 deg.C for 10-60min, and maintaining for 2-4 h;

the high-temperature biscuiting process comprises the following steps: continuing heating and cracking the sample and the mold after low-temperature curing in a vacuum furnace, heating to 350 ℃ within 100-200min, and preserving heat for 2-4 h; heating to 500 deg.C for 60-120min, and maintaining for 2-4 h; raising the temperature to 1400 ℃ at the temperature rise rate of 2-5 ℃/min, and preserving the heat for 1-2 h.

6. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (2), the high-temperature infiltration sintering process comprises the following steps: sintering at 1600-1800 deg.c for 30-60min by embedding process.

7. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (2), the amount of the zirconium or zirconium-silicon alloy is 200% of the mass of the porous carbon-containing preform.

8. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (3), the ceramic precursor is one or more of polyborosilazane, polycarbosilane and an organic zirconium precursor; in the ethanol solution of the ceramic precursor, the content of the ceramic precursor is 60-90 wt%.

9. The method for preparing a chopped silicon carbide fiber reinforced ZrC multilayer cladding material as claimed in claim 1, wherein: in the step (3), the high-temperature ceramic conversion process comprises the following steps: heating to 120 ℃ at the heating rate of 2-5 ℃/min, and keeping the temperature for 1-2 h; heating to 350 ℃ at the heating rate of 2-5 ℃/min, and keeping the temperature for 1-2 h; heating to 500 ℃ at the heating rate of 2-5 ℃/min, and keeping the temperature for 1-2 h; raising the temperature to 1400 ℃ at the temperature rise rate of 5-10 ℃/min, and preserving the heat for 1-2 h.

10. A short cut silicon carbide fiber reinforced ZrC multilayer cladding material is characterized in that: prepared by the preparation method of any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of ZrC ceramic materials, in particular to a chopped silicon carbide fiber reinforced ZrC multilayer cladding material and a preparation method thereof.

Background

As nuclear power technology is continuously improved, pressurized water reactor nuclear power plants are being developed towards the goal of higher safety and better economy, and as one of the most important components of a reactor, the performance of fuel assemblies directly affects the safety and economy of the reactor.

Early on, the cladding material was made of Continuous Fiber Ceramic Composite (CFCC), made of aluminum fiber and aluminum matrix, however, it had the disadvantage that fission gases could pass through the compound, and the strength of aluminum after irradiation was greatly reduced, and its application in the field of cladding materials was not suitable. In general, zirconium alloy is mainly used as a cladding material of a pressurized water reactor fuel assembly, but as the internal irradiation time of the zirconium alloy is prolonged, the possibility of breakage of the zirconium alloy is increased, and the zirconium alloy has to be unloaded under the condition that the fuel assembly has quite residual reactivity, so that the cost is higher. At present, the silicon carbide fiber reinforced silicon carbide ceramic matrix composite (SiC) is developing abroad_f/SiC) as cladding material, which has a multilayer structure with an intermediate layer of SiC_fThe inner surface of the pipe is a compact SiC coating, and the outside of the pipe is a thick compact SiC layer, so that the sealing property and the corrosion resistance of the cladding material are ensured, and the cladding material has better toughness and strength and is an ideal cladding material.

Chinese scienceInstitute of Ningbo material technology and engineering research discloses a fiber toughened ceramic matrix composite with a ternary layered MAX phase interface layer and a preparation method (CN106083117A) thereof, low-oxygen content silicon carbide fibers are obtained through molecular regulation, and high-aluminum (higher than 1 wt%) silicon carbide fibers containing an Al-C chemical bond structure are proposed for the first time to be expected to form special fiber materials for core formation. The development behavior of a ternary laminated MAX phase irradiation damage mechanism and a defect structure is researched, the ternary laminated MAX phase material is proposed and realized for the first time to serve as a SiCf/SiC intermediate layer, and heavy ion irradiation research shows that the novel intermediate layer has good anti-swelling property. Meanwhile, the Ti-Si-C ternary phase diagram is utilized to control the material phase gradient distribution of the connecting layer, so that reliable connection with high strength, low interface stress, irradiation resistance and corrosion resistance is obtained, and TiC/Ti is realized₃SiC₂The full carbide gradient connecting layer is connected with SiC, the problem of interface thermal stress is effectively solved, and the four-point bending strength of the obtained connecting structure is as high as 325 MPa. In addition, a silicon carbide ceramic seamless connection solution is also provided, and a series of 'sacrificial' type ceramic solders are developed to realize integrated sealing of the silicon carbide ceramic and the composite material.

Northwest industrial university discloses a one-step method for preparing a SiC composite material cladding tube (cn201610429768.x), which comprises the following technical process steps: introducing a layer of one-dimensional SiC nano material on the surface of a mould, weaving a layer of continuous SiC fiber outside the nano material layer to form a SiC fiber preform, and introducing an interface layer into the SiC fiber preform by adopting a chemical vapor deposition method; the interface layer is a pyrolytic carbon PyC layer, a mixed layer of pyrolytic carbon and SiC or Ti₃SiC₂A layer; and adopting a chemical vapor infiltration process to perform densification treatment on the treated SiC fiber preform, and demolding to obtain the SiC-based cladding tube with a three-layer structure. The process improves the density of the SiC-based cladding tube and the combination between layers, and shortens the preparation period of the SiC-based cladding tube.

However, the preparation processes all adopt silicon carbide fiber preforms, special equipment is needed for weaving, and the process is complex; and the densification is carried out by adopting a chemical vapor infiltration process, the process time is long, the energy consumption is high, the density is not high, the pore defect is easy to form, and the material performance is influenced.

Disclosure of Invention

The invention aims to provide a chopped silicon carbide fiber reinforced ZrC multilayer cladding material which has a multilayer structure, high strength and high toughness; the invention also provides a preparation method of the cladding material, which realizes the high-efficiency and equal-cost preparation of the cladding material and simultaneously ensures the economy and the safety of the cladding material.

The preparation method of the chopped silicon carbide fiber reinforced ZrC multilayer cladding material comprises the following steps:

(1) taking aggregate, chopped SiC fiber, carbon black and thermosetting phenolic resin as raw materials, adding a dispersing agent, and mixing, injection molding, low-temperature curing and high-temperature biscuiting to obtain a porous carbon-containing prefabricated body;

(2) carrying out high-temperature infiltration sintering on the porous carbon-containing prefabricated body by taking zirconium or zirconium-silicon alloy as an infiltration agent to obtain a fiber toughened ultrahigh-temperature ceramic tube;

(3) and taking an ethanol solution of a ceramic precursor as a sol, and carrying out lifting coating and high-temperature ceramic conversion on the fiber-toughened ultrahigh-temperature ceramic tube to obtain the chopped silicon carbide fiber-reinforced ZrC multilayer cladding material.

In the step (1), the raw materials in percentage by mass are:

the addition amount of the dispersing agent is 2-5% of the total mass of the aggregate, the chopped SiC fiber and the carbon black.

Wherein the aggregate is one or two of ZrC and SiC, and the particle size is D50-0.5-5.0 μm;

the length of the short-cut SiC fiber is 1-3 mm;

the thermosetting phenolic resin is one or more of barium phenolic resin, ammonia phenolic resin and boron phenolic resin;

the dispersant is polyacrylic acid.

The mixing process comprises the following steps: the open mill adopts a heating belt for heat preservation, the mixing temperature is 30-90 ℃, and the mixing time is 6-12 h;

the injection molding process comprises the following steps: the injection temperature is 50-120 ℃, the mould is made of graphite and is placed in a vacuum device, and the vacuum degree is 0.1-1 kPa.

The low-temperature curing process comprises the following steps: placing the injection molded biscuit and a mold in a vacuum furnace, wherein the vacuum degree is 0.1-1kPa, heating to 120 ℃ for 10-30min, and preserving heat for 1-2 h; heating to 160 ℃ for 10-60min, and keeping the temperature for 1-2 h; heating to 200 deg.C for 10-60min, and maintaining for 2-4 h.

The high-temperature biscuiting process comprises the following steps: continuing heating and cracking the sample and the mold after low-temperature curing in a vacuum furnace, heating to 350 ℃ within 100-200min, and preserving heat for 2-4 h; heating to 500 deg.C for 60-120min, and maintaining for 2-4 h; raising the temperature to 1400 ℃ at the temperature rise rate of 2-5 ℃/min, and preserving the heat for 1-2 h.

In the step (2), the high-temperature infiltration sintering process comprises the following steps: sintering for 30-60min at the temperature of 1600-2000 ℃ by adopting an embedding method, wherein the dosage of the zirconium or zirconium-silicon alloy is 200% of the mass of the porous carbon-containing prefabricated body.

In the step (3), the ceramic precursor is one or more of polyborosilazane, polycarbosilane and an organic zirconium precursor; in the ethanol solution of the ceramic precursor, the content of the ceramic precursor is 60-90 wt%.

The high-temperature ceramic conversion process comprises the following steps: heating to 120 ℃ at the heating rate of 2-5 ℃/min, and keeping the temperature for 1-2 h; heating to 350 ℃ at the heating rate of 2-5 ℃/min, and keeping the temperature for 1-2 h; heating to 500 ℃ at the heating rate of 2-5 ℃/min, and keeping the temperature for 1-2 h; raising the temperature to 1400 ℃ at the temperature rise rate of 5-10 ℃/min, and preserving the heat for 1-2 h.

And circularly operating the lifting coating process and the high-temperature ceramic conversion process to prepare the sol-gel compact coating until the thickness requirement is met.

The chopped silicon carbide fiber reinforced ZrC multilayer cladding material is prepared by the preparation method.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, by designing the raw material composition, curable phenolic resin is introduced into the ceramic powder as a bonding component, so that the molding efficiency of the cladding material is improved, and simple and efficient injection molding is realized;

(2) the invention develops a rapid densification process for a high-strength and high-toughness cladding material, which increases the strength and toughness of the material by introducing silicon carbide chopped fibers and realizes rapid densification of the cladding material by adopting an embedding infiltration process;

(3) the invention develops a rapid preparation method of the compact layer, and the sol-gel method is adopted to prepare the high-performance compact sealing layer, so that the process is simple and the thickness is controllable;

(4) the invention prepares the cladding material with multilayer structure, high strength and high toughness by designing reasonable raw material components and organization structures and reasonable process arrangement, and has simple and easy process, high efficiency and low cost.

Drawings

FIG. 1 is a flow chart of the preparation process of the chopped silicon carbide fiber reinforced ZrC multilayer cladding material.

Detailed Description

The present invention will be further described with reference to the following examples.