Properties And Fabrication Of Three-Dimensional Needled Carbon/Silicon Carbide Friction Material

Carbon fiber reinforced silicon carbide (C/SiC) brake material is a new type of friction materials developed in recent years. Compared with traditional metal, semimetal and carbon/carbon composite materials, C/SiC exhibits many outstanding advantages like low density, stable coefficient of friction, low wear, large brake ratio and long service life. As a result, it has bright application prospect in the fields of high-speed train, automobile and airplane. At present, how to reduce the manufacturing cost and improve the performance of C/SiC composite is the key problem to be solved.On the basis of systematically exploring vacuum pressure infiltration (VPI) process, a new unidirectional pressure infiltration (UPI) process is proposed in this paper. With the combination of polymer infiltration-pyrolysis (PIP) and liquid silicon infiltration (LSI) process, a lightweight and low-cost needled C/SiC friction material with density 1.68 g/cm~3 has been fabricated and the friction and wear performance have been tested and analyzed. The main contents and results of this work are as follows:(1) The factors influencing the densification of three-dimensional needled carbon felt with VPI process has been studied. The results show that the process of VIM is influenced by many factors synthetically. The influencing factors such as concentration and viscosity of infiltrant solution, vacuum degree, applied pressure and temperature interacted with each other, which makes it hard to completely densify the 3D needled carbon felt with VPI process.(2) With UPI pyrolysis process, some porous carbon/carbon (C/C) materials with density 1.22 g/cm~3 and porosity 24.7% were prepared. And the factors influencing the densification with UPI pyrolysis process were investigated. The results show that the concentration of infiltrant solution, gas pressure and holding time, high temperature heattreatment and times all influence the densification of the 3D needled carbon felt. Especially, when the disc samples were heat treated and then infiltrated with UPI process after first round of infiltration and curing, the weight gain and density of the sample both increased obviously. The use of UPI-curing-heattreatment cycling process can greatly improve densification.(3) With the porous C/C composite prepared by UPI pyrolysis process as preform, a new lightweight C/SiC friction material has been fabricated using LSI process, with...