Study On Experiment Of The Graphite Foam Material

With the rapid development of aeronautics and space, automobile, communication and information industries, it has put forward some more severe requirements in the field of modern materials, such as high thermal conductivity, erode resistant and good mechanical properties. In order to meet them, the graphite foam material on behalf of the heat conduction technique with new materials has appeared.The mesophase pith-derived graphite foam is a porous material, which owns the excellent thermal-phsical property of small density and great thermal conductivity. Using the graphite foam material to produce a variety of radiators could greatly decrease the weight and volume of the radiators.The uniformity of size and distribution of honeycombed pores in graphite foam have a large influence on its thermophysical and mechanical performances. For experimental optimization, a pores'distribution uniformity coefficient based on the standard deviation of pores'sectional area was presented as a synthetical index to estimate the uniformity of size and distribution of pores for porous materials, meanwhile advanced a reference to the estimetion for the similar porous media.In this paper, the orthogonal design was adopted to optimize the processing parameters on the graphite foam forming experiment. Meanwhile, The effect of foaming temperature (A), foaming time (B), coking temperature (C), coking time (D), foaming pressure (E) and heating rate (F) on the pores uniformity coefficient were analyzed and discussed. It can be found that the influence order is E > F > A > B > C > D by using of range analysis and variance analysis. Consequently, the optimum condition was obtained from the orthogonal test data. Additionally, the samples with good uniform pores distribution were formed near the optimum condition. Moreover, the direction and clue were provided on the further research of graphite foam experiments.This paper introduces the experiment of material's thermogravimetric analysis and the system, steps and technological parameter's controlling means of the graphite foam's forming and charring process. Then it demonstrates the photos of test sample and the SEM photos of microstructure adopted by different preparation technology.In the process of forming and charring, various kinds of parameters take great impacts on the microstructure, thermal conductivity and mechanical properties. This paper describes and analyses the tests of the two stages, especially the effect of different foaming technology parameters on the properties of the graphite foam, such as the foaming pressure, the heating rate, the foaming and coking temperature, the constant temperature time, the gravity and etc. It's essential to analysis them for material's high temperature treatment.