Influence of the microstructure of pyrocarbon on friction and wear properties of C/C composites

With the carbon fiber integrated felts used as preforms, two different types of carbon-carbon(C/C) composites, namely, rough laminar (RL) structure materials and smooth laminar (SL) structure materials were fabricated by thermal gradient CVI process. The microstructure and thermal physical properties of the materials in different conditions were investigated by means of microscopy, X-ray diffraction, hardness tester, thermal conductivity tester respectively. Furthermore, the frictional and wear properties of the materials were also investigated. The results show that the effects of microstructure of pyrocarbon on the frictional properties outweigh by far the effects of bulk density on the corresponding properties when the bulk density amounts to a certain degree, both in as-deposited and in heat-treated condition, the frictional properties of RL structure material is obviously superior to the SL structure materials, which implies that the decisive factor in determining the frictional behavior of C/C composites turns to be the microstructure of pyrocarbon.