Preparation And Investigation Of Mechanical And Tribological Properties Of C/C-SiC Composites

Abstract:C/C-SiC composites are that carbon fiber reinforced carbon and SiC dual matrix composites. It with low density(≤2.4g/cm3), high thermal shock resistance, good oxidation resistance, high coefficient friction, good abrasive resistance, long service life and other advantages. Therefore, C/C-SiC are promising candidates for advanced friction materials in future.In this paper, in order to shorten preparation period, optimize process route and reduce production costs, explore the impregnated-moulded-infiltration new preparation technology to prepare short carbon fiber reinforced C/C-SiC composites on the basis of existed preparation technology of C/C-SiC composites. The influence of C/C porous’pore structure to infiltration and different treatment process of C/C-SiC composites to mechanical properties and tribological behavior were investigated. The results show that:(1) Impregnated-moulded technology prepared short fiber reinforced C/C porous body with density of1.29g/cm3and the opening pore rate of27.09%after densification. Compare with overall felt and net-like chopped fiber felt porous body, short fiber reinforced C/C porous body has more uniform fiber distribution and pore size distribution, and it has less obturator.(2) The type and shape of pores in C/C porous body have a great influence of the melt infiltration process. The obturator against liquid Si infiltration, through hole and curved hole are conducive to infiltration of liquid Si. Formula derived by the capillary force is known that the lager of perimeter/area, the greater of the capillary force. The holes of short fiber reinforced C/C porous body are rod-shaped. It is advantageous to melt infiltration.(3) The parallel direction and vertical direction of short carbon fiber reinforced C/C-SiC composites compressive strength in between90.3～227.0MPa and47.1～137.9MPa. The bending strength in the range of 69.03～93.37MPa. The impact toughness in the range of6.1～11.0KJ/m2.(4) Short carbon fiber reinforced C/C-SiC composites with the friction coefficient about0.25～0.54, and the linear wear rate changes from0.340×10-2cm3/MJ to3.31×10-2cm3/MJ. Composites formed a more complete friction membrane during braking, and it’s braking is relatively stable. The main wear mechanism of C/C-SiC composites included grain wear, adhesive wear and fatigue wear. In the actual process, there were usually several wear exist together, moreover one wear occurred can induced other wear. Figures46, Tables9, References95.