A kind of ultra-high thermal conductivity, high-strength graphite block material and preparation method thereof

Abstract

The invention relates to an ultra-high thermal conductivity and high strength graphite block material and a preparation method thereof, belonging to the technical field of graphite block materials and preparation technology thereof, and solves the problem of low mechanical properties existing in the current high thermal conductivity graphite block material. It adopts high-purity natural graphite powder as heat transfer enhancer, high-quality mesophase pitch as binder, silicon-titanium-molybdenum three-component as catalytic graphitization aid, and is sintered by high-temperature hot pressing. The thermal conductivity of the graphite block material provided by the invention is greater than 600W / mK, and the bending strength is greater than 50MPa. It is expected to play an important role in the fields of high heat flow and diverse working conditions such as aerospace vehicle thermal protection, nuclear fusion first wall, and high power density electronic devices. effect. The preparation method of the invention is simple, the preparation period is short, the yield is high, the repeatability and stability are good, and it is suitable for large-scale production.

Description

technical field [0001] The invention belongs to the technical field of graphite block material and its preparation process, and specifically relates to an ultra-high thermal conductivity, high-strength graphite block material and a preparation method thereof. Background technique [0002] The development of high heat flow and diversified working conditions in the high-tech field puts forward high requirements on the heat carrying and heat dissipation of thermal management materials. Materials must not only have high thermal conductivity and light weight, but also have high-temperature load-bearing and excellent mechanical properties. [0003] Graphite material is characterized by its ultra-high theoretical thermal conductivity (the theoretical thermal conductivity of single crystal graphite is as high as 2200W / mK, which is 5-12 times that of traditional metal thermal controls), light weight, low expansion coefficient, corrosion resistance, high temperature resistance and easy...

AI Technical Summary

Problems solved by technology

In recent years, researchers have gradually realized the high thermal conductivity of natural flake graphite (the in-plane thermal conductivity is nearly 1000W / mK) and the easy graphitization characteristics of the binder mesophase pitch. Ultra-high thermal conductivity graphite bulk material with a thermal conductivity of 600~745 W / mK was prepared under high temperature hot pressing at 3000°C [patent: CN 200610102224.9], and this material has been successfully applied to the thermal management of high power density devices of my country's Beidou navigation satellite device, but its low mechanical properties (bending strength about 20MPa) affect its processability and application fields, and it is only used in some heat dissipation fields that do not require high material strength

The reason is that the addition of appropriate silicon and titanium catalytic components greatly promotes the transformation process of carbon matrix to graphite structure, which is beneficial to the improvement of material conductivity, but all silicon components escape at high temperature and titanium components at high temperature Most of the escape phase is the main reason for the decrease in the mechanical properties of hot-pressed recrystallized graphite

Zhao Yun et al [Carbon, 2013, 53: 313-20] tried to improve its mechanical properties by adding a small amount of chopped high thermal conductivity mesophase pitch-based carbon fibers (4~5mm), but found that the enhancement effect was minimal