Situ Reaction Method C / C - Sic Composite Friction Properties And Oxidation Resistance

Braking material is an important guarantee that the high speed train can move in a safety way, it can influence the speed of the train . As a kind of braking material, C/C-SiC composites have the characteristics of low density, high anti-thermal shocking, excellent oxidation resistance and good friction properties. Short carbon fiber reinforced C/C-SiC materials are prepared by the way of in-situ reaction in this paper, and the wear behavior of C/C-SiC composites is also tested, the factors that can influence the wear behavior of C/C-SiC composites are studied. The paper also including the investigation of oxidation performance about C/C-SiC composites, and its regularity of oxidation are discussed.(1) The important factors that can influence the wear behavior of C/C-SiC composites are the content of SiC. In the condition of testing for the semimetal brake material, comparing with the C/C-SiC composites with volume content of SiC is 22 percent, that with volume content of SiC is 37 percent have the merits of higher friction coefficient, the lower wear of material and the counterpart.( 2 ) With the different content of SiC, the wear behavior of C/C-SiC composites behave different regularity varying with the speed of braking. In the range of 5m s-1 and 28 m s-1 of the speed of braking, for the C/C-SiC composites of less volume content of SiC (10 percent), the friction coefficient of material rise afer a time of reducing ,eventually it reduce with the raise of the speed of braking. For the C/C-SiC composites of more volume content of SiC (33 percent), the friction coefficient of material reduce afer a time of rising with the raise of the speed of braking.(3) In the range of 0.35MPa and 1.70 MPa of the pressure of braking, the friction coefficient of material reduce afer a time of rising, the wear of material rise afer a time of reducing, the wear of counterpart always rises.(4) With the increase of the energy in the process of braking , the friction coefficient of material reduce , the wear of materialincrease, the wear of counterpart also increase greatly, the wear behavior of C/C-SiC composites have little change in the environment of dry and humid.(5) In the temperature of 600C, the weight loss ratio of C/C-SiC composites increase as the regular of linearity and then slower with the prolong time of oxidation in the air, the weight loss ratio of C/C-SiC composites achieve a constant after oxidation in a long time of 54 hours, The oxidation of SiC is unobvious in 600 C, the obvious oxidation of SiC begin at 800 C, in 1000C,the oxidation of SiC increased.