加热条件对炭泡沫材料孔结构和性能的影响

以AR沥青为原料,利用高压釜在不同恒温条件下制备了炭泡沫,并测定了其孔结构、体积密度、显气孔率、压缩强度、常温热导率以及微晶参数.结果表明:相对于短恒温时间,长恒温时间制得的炭泡沫孔径大(412nm)、显气孔率高(83.82%)、体积密度小(0.34g/cm~3)、压缩强度高(4.92MPa),多孔连通结构更丰富.经过石墨化处理后,石墨泡沫呈现出较高的常温热导率(71.34W/(m·K))和较小的层片间距d_(002)(0.33556nm).石墨泡沫的常温比导热率能达到210(W·(m·K)~(-1)) /(g·cm~(-3)),是铜的5倍,铝的4倍.

Effect of heating conditions on pore structure and performance of carbon foams

Carbon foams were prepared from AR pitch in a high pressure/high temperature reactor under different heating conditions. Their pore structure, bulk density, porosity, compressive strength, thermal conductivity, and crystallite size parameters were measured. Foams produced using a long time at a constant foaming temperature exhibit bigger pore size (412 nm), higher porosity (83.82%), lower bulk density (0.34 g/cm~3), higher compressive strength (4.92 MPa), and more interconnected pores than that produced in a short time at the same constant foaming temperature, which exhibit high thermal conductivity (71.34 W/(m · K)) and low interlayer d-spacing (d_(002)) (0.335 56 nm) after graphitization at 2 800 ℃. The specific thermal conductivity of graphite foams can reach 210 (W · (m · K)~(-1))/( g · cm~(-3)), which is about five times greater than copper and four times greater than aluminum.