PREPARING C/ C COMPOSITES BY CVI WITHMULTI-FACTOR COUPLINGPHYSICAL FIELDS AND DISCUSSING THE DYNAMIC PROCESS

Installing special elect ric layer in preforms of carbon felt , C/ C composites were fabricated by chemicalvapor infilt ration (CVI) with multi-factor coupling physical fields , and the infilt ration conditions were optimized.The textures of pyrolytic carbons were observed using polarized light microscopy ( PLM) , and the graphitization degree of these C/ C composites was analyzed by XRD ; The effect of elect romagnetic field on the CVI and dynamicprocess of dual convective heat of outer thermogenesis and inner thermogenesis and mass rest rainning of consumingt ransfer , and three of deposition models were discussed. The result s show that the rate of deposition of pyrolyticcarbon is improved with multi-factor coupling physical fields , and the porous carbon-carbon preforms (260 mm ×60 mm ×20 mm) can be densified in one-cycle. C/ C composites with density of more than 1.7 g/ cm³ are obtainedwithin 20 h. Though optimizing the infilt ration conditions , some kinds of microst ructure of pyrolytic carbons can beobtained , ranging f rom rough laminar , smooth laminar , isot ropic and banded st ructure. Under the infilt ration conditions of 960 ℃and 0.1 kPa , the rough laminar of higher texture can be obtained.