Thermal gradient CVI for fabrication of carbon/carbon composites tubes

The plugging of the surface pores in the preforms which often occurs in isothermal CVI technology seldom happens in the thermal gradient CVI process, namely, the overcrusting is avoided. The thermal gradient CVI process is well suitable for fabricating symmetrical rings and tubes, so the preparation of carbon/carbon composites tubes by the thermal gradient chemical vapor infiltration (CVI) process was discussed in this paper. The microstructure of composites was analyzed and their mechanical properties, thermal expansion, and thermal conductivity were measured, which indicated that the carbon/carbon tubes were of high performance and were absolutely competent for the thermo-structure composite materials.