Car Brake With The Preparation And Properties Of C / C - Sic Composite

Carbon/carbon-silicon carbide(C/C-SiC) composite is a novel material developed in the new material field and has great prospect in brake fields due to excellent mechanical properties, especially outstanding friction-wear behavior. However, the processing cost of C/C-SiC composite restricts its domain use, and in order to break such limitation and apply it as auto brake materials, short fiber and reactive sintering could be adopted instead of continuous fiber felt and RMI(reactive melt infiltration) . In this paper, on the basis of the reviews on two respects: auto brake materials development and main manufacture way of C/C-SiC composite, the research work was focused on preparation technologies, carbon-silicon reaction mechanism and friction behaviors, and the main contents were as followings:1, C/C-SiC composites was manufactured through three major steps : mixing silicon powder , carbon powder, short carbon fiber and binder, molding compaction and reactive sintering at 1500℃. After continued dealing the densification ratio reachs 80% or above. The morphology, composition, structure of composite and interface were investigated by SEM, EDAX, XRD and OM. Meantime, discussed the reaction mechanism between carbon and silicon.2, Performed friction and wear experiment by MM-1000 test-bed with simulated train braking condition. Investigated tribology and wear performance or composite under dry and moist state. Explored the influence of matrix densification ratio, SiC content and surrounding humidity to frictional behavior of composite respectively. It was found that: dense matrix could help to decrease wear; high SiC content is favor to promote friction coefficient; composite still preserve the coefficient under moist surrounding.3, Simulated auto braking test was carried out according automobile industry standard QC/T582. Explored three most important aspect including brake efficiency, friction coefficent fade and recovery. Composite exhibit an excellent anti-fade performance and high friction coefficient. High SiC content could provide more hard sustaining pointwhich is benefit to maintain a high friction coefficient and its stability.4> In order to eliminate exterior effluence and comprehend braking characteristic of composite itself, fixed velocity friction test was adopted. The result showed that: friction coefficient could keep stable in the same temperature. The composite doesn't have a acute sensitivity to temperature, friction coefficient just have a little difference at different temperament. Wear have a reverse trend with temperament variation.5 ^ Tested the major mechanics performance of composite such as bending strength, compressive strength and shear strength which is related to braking. Developed the mechanism of material invalidation. Discussed the function of fiber distributing and orientation, densification result and SiC content during material breakage.