Method for improving wettability of brazing filler metal based on surface modification of carbon-carbon composite

Abstract

The invention discloses a method for improving the wettability of brazing filler metal based on surface modification of a carbon-carbon composite. Carbon nanotubes grow in situ in a hole formed afteroxidation pretreatment of the carbon-carbon composite and are used as a bridge to promote liquid brazing filler metal to be wetted and spread in a brazing process and improve the capacity of filling the hole. The carbon nanotubes grow on the surface of the carbon-carbon composite by selecting a chemical vapor deposition method, and the carbon-carbon composite is brazed or brazed together with metal by selecting the brazing filler metal capable of wetting the carbon-carbon composite after the carbon-carbon composite is subjected to surface modification. By using the method, the surface of the carbon-carbon composite which is not brazed is subjected to high-temperature oxidation, and CNTs grow on the surface of the carbon-carbon composite which is not brazed, an infiltration interface structure is formed between a brazinrg seam and the carbon-carbon composite, and the spreading and filling capacity of the liquid brazing filler metal is improved, so that the reaction of the brazing fillermetal and the carbon-carbon composite is more sufficient, and the method has important significance in reducing residual stresses in joints and improving the connection performance of the joints.

Description

technical field [0001] The invention relates to a method for improving the brazing connection performance of itself or metal by modifying the connection surface of carbon-carbon composite materials during the brazing process. More specifically, it relates to a high-temperature oxidation treatment on the surface of carbon-carbon composites to form an impregnated interface in the brazed joint to increase the connection area and form a pinning effect, and to form a high-temperature oxidation treatment of carbon-carbon by chemical vapor deposition. A method of growing carbon nanotubes (CNTs) on the surface of composite materials to improve the wettability of liquid solder to the surface of composite materials. At the same time, CNTs react in situ during the brazing process to form compounds with low thermal expansion coefficients in the interface connection area, which further relieves residual stress and improves joint connection performance. Background technique [0002] Carb...

AI Technical Summary

Problems solved by technology

However, due to the large difference in physical properties (thermal expansion coefficient and elastic modulus, etc.) between metal and carbon-carbon composite materials, the joint after metallurgical bonding will form a large residual stress during the cooling process, especially for the straight interface structure. It is very easy to produce cracks due to residual stress, which will greatly reduce the connection performance and reliability of the joint, and limit its application with metal connectors

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