Method for enhancing heat conduction performance of foamy carbon with high aperture ratio

Abstract

The invention relates to a method for enhancing heat conduction performance of foamy carbon with high aperture ratio, aims at solving the defects that the foamy carbon with high aperture ratio is low in heat conduction and poor in dynamic performance. In the method, the hole wall of the foamy carbon is enhanced by medium-phase pitch through vacuuming/pressurization dipping-gradient pressure foaming method for a plurality of times, the enhanced foamy carbon is further subject to high-temperature graphitizing processing, thus forming enhanced type high-conduction foamy carbon. For the enhanced foamy carbon, heat conductivity of the volume is improved greatly, and the dynamic performance is improved obviously.

Description

technical field [0001] The invention relates to a method for enhancing the thermal conductivity of foamed carbon with high porosity (the porosity is greater than 60%), and belongs to the technical field of inorganic porous materials. Background technique [0002] High thermal conductivity foam carbon is a porous carbon material with low density, high porosity and high thermal conductivity. In addition to the above advantages, it also has excellent properties such as corrosion resistance and high temperature resistance of carbon materials. It is a function with wide application value. Materials can be used in thermal management, sound absorption and noise reduction, impact resistance, new energy batteries or capacitors and other fields. In the field of thermal management, foamed carbon with high thermal conductivity can be used as heat exchangers, heat sinks, phase change heat storage, radiators and other materials. Filling, flow, etc. create conditions that greatly improve ...

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Problems solved by technology

However, the foamed carbon with high open cell ratio formed by mesophase pitch foaming usually has weak cell walls, and the apparent thermal conductivity and macroscopic mechanical properties of the material are very low, which cannot meet the application requirements.

[0004] Therefore, researchers have carried out a lot of foam carbon enhancement research, the main methods are adding substances to the foam carbon precursor (such as adding carbon microspheres, graphite powder, clay, etc.), precursor modulation method (such as pre-oxidation modification , fluorination modification, etc.), chemical vapor infiltration method, filling method, metal coating method, etc., the first two methods are to change the foaming characteristics of the precursor to form high-strength carbon foam, although the mechanical properties of carbon foam have been compared. However, the thermal conductivity of the material is not greatly improved, but the specific thermal conductivity is significantly reduced; the latter three methods are to further enhance the foamed carbon on the premise of keeping the original foamed carbon structure basically unchanged, among which the chemical vapor infiltration method The long-term deposition of gas-phase carbon source can achieve uniform reinforcement of the foam carbon pore wall, but the enhancement period is long, and it is easy to block the pores of the foam carbon surface; the filling method is to fill the foam carbon pores with mesophase pitch substances, and then carbonize to form Filling, the enhancement of this method usually results in the filling of the pores, rather than the enhancement of the pore wall, resulting in a significant reduction in the available channels of the material; This method, like the chemical vapor infiltration method, forms a reinforcing layer on the pore wall of the foamed carbon, which can effectively improve the mechanical properties of the foamed carbon, but due to the high density of the metal coating, low temperature resistance, and poor thermal matching with the foamed carbon , resulting in many problems in the application of enhanced carbon foam

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