Effect Of Nickel Infiltration On Chemical Vapor Infiltration Process And Properties Of C/SiC

Carbon fiber reinforced silicon carbide composilcs(C/SiC) exhibit outstanding properties, such as low density, high strength, high temperature resistance, oxidation resistance and without catastrophic destruction, it is applied to airspace and aerospace Held widely. With the extension of the application field, different working condition demand C/SiC possessing different thermophysical. high-temperature and mechanical properties. The application of C/SiC could be extended through the addition of metal to the matrix to vary the properties. Except to superior heat and electricity conduction properties, nickel has catalytic effect on the fabrication of carbon nanomaterials, furthermore, it can be used for joining of SiC and C/SiC to metal or themselves. So. the study of the influence of nickel on the fabrication process and performance of C/SiC composite has great theoretical significance and practicable value.In this research, nickel was introduced to C/SiC with liquid infiltration and reduction method, the catalytic effect of nickel on the process of chemical vapor infiltration pyrolysis carbon and SiC were investigated, moreover, the influence of nickel on the thermalphysical and mechanical properties of C/SiC were researched. The main contents and conclusions are as follows:(1) Liquid infiltration and reduction technique of Ni(NO₃)₂. solution to the C/SiC composite was investigated. The results show that nickel could be introduced into the micropore of the C/SiC, the main influencing factors of mass gain are porosity of the original C/SiC composite and cycling times. Nickel infiltrated to the pores among fiber bundles and the filaments exists in the form of granule agglomerate.(2) The influence of nickel on the process of CVI PyC was investigated. 1 he results show that PyC deposition could be improved by nickel introduction, the mass gain reaches to the maximum when the nickel content is 4.4%, and the catalytic effect reduced with the increase of deposition time. PyC deposited among liber bundles existed in the form of regular fine granule agglomerate when nickel contained in the C/SiC. TEM analysis shows that graphitization of deposited PyC achieved with the function of nickel. Carbon on the surface of reaction product takes on graphite layer structure with the layer space 0.341nm.(3) The influence of nickel on the process of CVI SiC was investigated. The results show that during CVI SiC process, nickel reacts with SiC to form Ni₂Si: Nickel has no catalytic effect on SiC deposition. TEM analysis shows that nickel...