Research On Preparation And Microstructures Of Zirconium Doped C/C Composites

In order to solve the problems of refractory metal oxide and carbide inhomogeneous distribute in C/C composites. In this paper, three kinds of zirconium doped C/C composites were prepared by different materials and processes. The existing form,micro-morphology,crystalline state and distribution of zirconium in C/C composites were researched. The anti-oxidation behaviors of zirconium doped C/C composites were also studied.1,Taking zirconium oxchloride as the raw material, the liquid precursor solution containing zirconium was synthesized. The pure C/C composites with different densities were added with zirconium by vacuum impregnation method. The densities and contents of ZrO2 in the C/C composites were researched. The existence form and distribution of zirconium in the material were studied. The anti-oxidation performance of zirconium doped C/C composites was studied. The results showed that the liquid precursor containing zirconium was entirely converted into nano-ZrO2 and nano-ZrC, after treated at 1000℃and 1600℃. They distributed in surface of material, the inner matrix and the carbon fiber surface evenly. The ZrC was generated by liquid-phase reaction mechanism at high temperature.Compared with pure C/C composites, the anti-oxidation performance of C/C-nanoZrO2 and C/C-nanoZrC composites has improved significantly.2,Taking zirconium acetate solution and petroleum pitch as raw materials, the ZrO2 content up to 70% of the C/C-nanoZrO2 composites and C/ZrC composites was prepared by impregnation method. The densification law and anti-oxidation performance of the material was researched. The existence form and distribution of zirconium in the material were studied. The results showed that the doped zirconium was entirely converted into monoclinic crystal nano-ZrO2 and cubic crystal nano-ZrC after treated at 1000℃and 1600℃. They distributed in the inner matrix and the carbon fibers surface evenly. Compared with pure C/C composites, the anti-oxidation performance of zirconium doped C/C composites has improved significantly. The ZrC was generated by liquid-phase reaction mechanism at high temperature processing. In the process of generated ZrC, the nano-ZrO2 reacts with both the carbon fibers and matrix carbon, made the carbon fibers generate micro-holes and defects and lower the enhanced function of the carbon fibers.3,Zirconium oxybenzoate was synthesized. Taking it as raw materials, different content of zirconium modified pitch were preparation. The influences of zirconium content to the performance of modified pitch were studied. The zirconium doped C/C composites was prepared with zirconium content of 3% modified pitch. The existence form and distribution of zirconium in the material were studied. The anti-oxidation performance of zirconium doped C/C composites was studied.The results showed that the softening point and viscosity of zirconium-contenting pitch were added with the content of zirconium increases. The Zirconium oxybenzoate was entirely converted into nano-ZrO2 and nano-ZrC, after treated at 1000℃and 1600℃. They distributed in the inner matrix and the carbon fiber surface evenly. Compared with pure C/C composites, the anti-oxidation performance of zirconium doped C/C composites has improved.