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Preparation method of a Cf/SiC composite ordered porous ceramic joint

A technology of composite materials and porous ceramics, which is applied in the field of preparation of ordered porous ceramic joints of Cf/SiC composite materials, can solve problems such as difficult welding, difficult wetting, and difficult brazing, and achieve effective connection, enhanced connection strength, and effective connection. good sequence effect

Inactive Publication Date: 2012-11-28
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the processing performance of existing Cf / SiC composite materials is poor, and it is difficult to directly form large-sized or complex-shaped components, which usually need to be realized by joining technology. Therefore, Cf / SiC composite materials and the connection between metals is a key problem that must be solved for the wide application of Cf / SiC composite materials
The main problems in the connection of existing Cf / SiC composite materials are as follows: (1) Cf / SiC composite materials have a high melting point and can be decomposed at high temperatures It makes it difficult to connect by fusion welding; (2) The conductivity of Cf / SiC composites is poor, making it difficult to weld by arc or resistance welding; (3) Cf / SiC composites makes it impossible to connect solid phases by applying high pressure; (4) The chemical inertness of Cf / SiC composites makes it difficult to It is not easy to wet and cause brazing difficulties; (5) The anisotropy of the Cf / SiC composite material and the difference in thermal expansion coefficient with the connection layer make it difficult to guarantee the reliability of the connection

Method used

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  • Preparation method of a Cf/SiC composite ordered porous ceramic joint
  • Preparation method of a Cf/SiC composite ordered porous ceramic joint
  • Preparation method of a Cf/SiC composite ordered porous ceramic joint

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Put a clean C of 15mm×10mm×5mm f Inject the above-mentioned emulsion into a tall glass vessel with a rectangular small piece of / SiC composite material, the injection height is 20cm, and let it stand for 10 days. After standing, carefully remove the upper layer of absolute ethanol solution with a syringe, and then let it dry naturally ; After the natural drying is completed, carefully take out the C which is deposited with silica gel beads (deposition thickness is 3mm) on the surface. f / SiC composite material rectangular piece, it is placed in the 250ml three-necked flask, the flask is equipped with an airtight separatory funnel, vacuumize, stop vacuumizing when the pressure in the flask is 4kPa, inject 40wt% polycarbonate into the above-mentioned flask The silane / tetrahydrofuran solution was vacuum impregnated for 10 hours. After the impregnation was completed, the solvent tetrahydrofuran was directly distilled off under reduced pressure; the C f / SiC composite rec...

Embodiment 2

[0025] Put a clean C of 15mm×10mm×5mm f Inject the above-mentioned emulsion into a tall glass vessel with a rectangular small piece of / SiC composite material, the injection height is 20cm, and then let the tall glass vessel stand for 10 days. After standing, carefully remove the upper layer of absolute ethanol solution with a syringe. Allow it to dry naturally afterwards; Carefully take out the C that the surface is deposited with silica gel beads (deposition thickness is 4mm) f / SiC composite rectangular small piece, it is placed in the 250ml three-neck flask, the flask is equipped with an airtight separatory funnel, vacuumize, stop vacuumizing when the pressure in the flask is 4kPa, inject 30wt% polycarbonate into the above-mentioned flask The silane tetrahydrofuran solution was vacuum impregnated, and the impregnation time was 10h. After the impregnation was completed, the solvent tetrahydrofuran was directly removed by distillation under reduced pressure (60°C / 5kPa); the...

Embodiment 3

[0028] Put a clean C of 15mm×10mm×5mm f Inject the above-mentioned emulsion into a tall glass vessel with a rectangular small piece of / SiC composite material, the injection height is 20cm, and then let the tall glass vessel stand for 10 days. After standing, carefully remove the upper layer of absolute ethanol solution with a syringe. Allow it to dry naturally afterwards; After the natural drying is completed, carefully take out the C with silica gel beads (deposition thickness is 2mm) deposited on the surface.f / SiC composite material rectangular chip, it is placed in the 250ml three-necked flask, the flask is equipped with an airtight separatory funnel, vacuumized, and when the pressure in the flask is 4kPa, stop the vacuumize, inject 50wt% PCS in the above-mentioned flask ( Polycarbosilane) tetrahydrofuran solution is vacuum impregnated, and the impregnation time is 10h. After the impregnation is completed, direct vacuum distillation (60°C / 5kPa) to remove the solvent tetra...

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Abstract

The invention provides a preparation method of a Cf / SiC composite ordered porous ceramic joint. The method comprises the steps of taking separated silicon oxide gelled pellets as raw material of a template to prepare a Cf / SiC composite silicon oxide gelled pellet joint template by using a natural sinking method; soaking the template with ceramic precursor; converting ceramic precursor PCS into SiC ceramic by using a normal pressure and high temperature cracking method and with N2 being a protecting gas after the soaking; eating up the silicon oxide gelled pellets with hydrofluoric acid, thus the Cf / SiC composite ordered porous ceramic joint is prepared. In the invention, an ordered porous structure is introduced into the end of the Cf / SiC composite material, thereby reducing bad effects of the complex micro structure of the Cf / SiC composite material on the jointing. At the same time, the heat stress in the jointing process is reduced by the transition of gradient material, thereby effectively improving the jointing quality of the Cf / SiC composite material. Therefore, the application of composite material in high technology and novel equipment fields of aerospace and military is improved.

Description

technical field [0001] The present invention relates to a C f Preparation method of ordered porous ceramic joint of / SiC composite material. Background technique [0002] C f / SiC composite material fully combines the advantages of carbon fiber and SiC matrix, showing low density, high strength, high toughness, high temperature resistance, ablation resistance, erosion resistance, high hardness and high wear resistance, etc., suitable for high temperature structural materials , has broad application prospects in high-performance weaponry, aerospace, energy technology, chemical industry, transportation industry and other fields. but existing C f / SiC composite materials have poor processing performance, and it is difficult to directly form components with large sizes or complex shapes, which usually need to be realized through connection technology. Therefore, C f The problem of the connection between itself and the metal of the SiC composite material is C f The key issue...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B37/00
Inventor 王浩周卿君王军王小宙谢征芳简科
Owner NAT UNIV OF DEFENSE TECH