Microstructure and ablation behavior of carbon/carbon composites infiltrated with Zr-Ti

Carbon/carbon(C/C) composites infiltrated with Zr-Ti were prepared by chemical vapor infiltration and reactive melt infiltration. Their microstructure and ablation behavior at different temperatures and time were investigated. The results show that C/C composites infiltrated with Zr-Ti have good interface cohesion between carbon fibers, pyrocarbon and carbide. Compared with C/C composites and C/C-ZrC composites, the synthesized sample with Zr0.83Ti0.17C0.92 and Ti0.82Zr0.18C0.92 exhibits better ablation resistance at 2500 degrees C due to the newly formed protective layer composed of ZrTiO2 pinned by ZrO2 grains after ablation. The ablation resistance of the sample with Zr0.57Ti0.43C1.01 increased gradually with the decrease of temperature from 3000 degrees C to 2000 degrees C, whereas the ablation resistance of the sample with Zr0.83Ti0.17C0.92 and Ti0.82Zr0.18C0.92 first increased obviously and then decreased slightly. In addition, the work indicates that surplus particles or liquid phases of oxides cannot protect the matrix, and that the liquid oxides may even cause severe ablation. Furthermore, a protective layer of oxides tends to be formed with the increase of ablation time. (c) 2012 Elsevier Ltd. All rights reserved.