Silicon carbide ceramic connection method and silicon carbide cladding

A technology of silicon carbide ceramics and connection methods, which is applied in the field of nuclear energy materials, can solve the problems of reducing joint reliability, pores, and large volume shrinkage, and achieve the effects of reducing pore defects, simple connection process, and improving air tightness

Inactive Publication Date: 2021-05-07
CHINA NUCLEAR POWER TECH RES INST CO LTD +3
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Only the precursor connection can realize the connection under the conditions of low temperature (<1500°C) and low pressure (<1MPa), and ensure that the joint after connection has good performance such as high temperature resistance, corrosion resistance and neutron radiation resistance, which is very promising. It is applied to the connection of SiC cladding, but due to the large volume shrinkage in the connection process, there are more pores in the connection layer, which makes the connection strength not high, and is not conducive to the sealing of SiC cladding
In the existing technology, adding fillers to the precursor can suppress the shrinkage rate during the connection process and improve the connection strength, but the introduction of fillers may reduce the high temperature resistance and radiation resistance of the joints, and reduce the reliability of the joints

Method used

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  • Silicon carbide ceramic connection method and silicon carbide cladding

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] With molecular formula (-SiHCH 3 -CH 2-) n polycarbosilane as a precursor, n = 17, the ceramic yield is 60wt%; 0.3wt% dicumyl peroxide is used as a curing agent, and the temperature is raised to 120°C at 3°C / min under an argon atmosphere After 2 hours of heat preservation, the temperature was raised to 150°C at 1°C / min for 2 hours, and then cooled with the furnace. The cured precursor was continued to be pretreated under a nitrogen atmosphere at a rate of 5°C / min to 500°C and kept for 2h to prepare a powder. Using absolute ethanol as an organic solvent, mix the above powder and absolute ethanol at a ratio of 25wt%:75wt% to obtain a slurry. After the silicon carbide-slurry-silicon carbide sandwich structure is formed, the above sandwich structure is first placed in an oven at 80°C for 2 hours, then placed in a tube furnace, and heated at 10°C / min to 1500°C for 2 hours. Cracking, cracking is carried out under nitrogen atmosphere. After cleavage, the thickness distribu...

Embodiment 2

[0052] With molecular formula (-SiHCH 3 -CH 2 -) The polycarbosilane of n is used as a precursor, n=10, and the ceramic yield is 70wt%; with 0.5wt% of dicumyl peroxide as a curing agent, with xylene as an organic solvent, after curing and pretreatment The volume ratio of the precursor to the organic solvent is 30wt%: 70wt%; a 100 μm thick slurry layer is coated on the surface of the end plug, and the connection is carried out according to the method in Example 1, wherein the curing temperature is 160 ° C, the pretreatment temperature is 800 ° C, and the cracking The temperature is 1200°C.

[0053] For the SiC ceramic connector prepared in Example 2, the thickness of the connecting layer is 5 μm; the room temperature shear strength of the SiC ceramic connector is 80 MPa, the high temperature shear strength at 1200 °C is 100 MPa, and the airtightness of the joint is 10 -10 Pa·m 3 / s, the corrosion rate of the connecting layer after hydrothermal corrosion is 5% higher than tha...

Embodiment 3

[0055] With molecular formula (-SiHCH 3 -CH 2 -) The polycarbosilane of n is used as a precursor, n=40, and the ceramic yield is 80wt%; with 0.5wt% metal platinum as a curing agent and xylene as an organic solvent, the cured and pretreated precursor and organic The solvent volume ratio is 35wt%: 65wt%; a 50 μm thick slurry layer is coated on the surface of the end plug, and the connection is carried out according to the method in Example 1, wherein the curing temperature is 140°C, the pretreatment temperature is 700°C, and the cracking temperature is 1500°C .

[0056] The thickness of the connecting layer of the SiC ceramic connector prepared in Example 3 is 4 μm; the room temperature shear strength of the SiC ceramic connector is 90 MPa, the high temperature shear strength at 1200 °C is 100 MPa, and the airtightness of the joint is 10 -11 Pa·m 3 / s, the corrosion rate of the connecting layer after hydrothermal corrosion is 2% higher than that of the base metal.

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Abstract

The invention discloses a silicon carbide ceramic connection method and a silicon carbide cladding, and the silicon carbide ceramic connection method comprises the following steps: S1, taking liquid polycarbosilane as a precursor, and adding a curing agent for curing treatment; S2, enabling the cured polycarbosilane to be subjected to heating pretreatment, and forming precursor powder; S3, mixing the precursor powder and an organic solvent to prepare slurry; S4, smearing the slurry between a SiC cladding tube and an end plug which are matched with each other, and forming a sandwich connection structure; and S5, performing high-temperature curing and cracking treatment on the sandwich connection structure, so that the slurry forms a connection layer which is tightly connected between the SiC cladding tube and the end plug. According to the silicon carbide ceramic connection method, high-strength connection of the SiC cladding and the end plug at a low temperature (less than or equal to 1500 DEG C) and without pressure is realized, filler does not need to be added, the pore defect of a middle connection layer is reduced, and the air tightness of a formed joint is improved; and the connection process is simple and has low requirements on equipment, and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of nuclear energy materials, in particular to a silicon carbide ceramic connection method and a silicon carbide cladding. Background technique [0002] As a structural ceramic material, silicon carbide (SiC) has good mechanical properties, high temperature resistance and corrosion resistance, as well as low neutron absorption cross section and good resistance to neutron radiation. Therefore, SiC is used in nuclear energy The field has a very broad application prospect, especially in the application of cladding materials in nuclear reactors. However, in order to realize the application of SiC cladding materials in extremely harsh high-temperature and high-irradiation working environments, it is necessary to ensure that the connection between SiC cladding and end plugs can withstand the impact of the above extreme working environment. [0003] In the existing SiC connection technology, the commonly used conne...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B37/00
CPCC04B37/00C04B2237/365C04B2237/083
Inventor 薛佳祥廖业宏刘彤任啟森翟剑晗马海滨
Owner CHINA NUCLEAR POWER TECH RES INST CO LTD
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