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Carbon–carbon composites are often used in high-temperature applications due to their high specific modulus, high specific strength, excellent heat resistance, high thermal shock resistance and chemical inertness. In this paper, the strength of carbon/carbon brake disks for automotive applications were tested and evaluated. The laminate material properties of carbon/carbon composites were evaluated via tension, compression and shear tests. The strengths of mechanically fastened composite joints for brake disks were tested and their failure criterion was established based on the maximum stress theory. Additionally, torsion tests of carbon/carbon brake disks were performed and the results were compared with those from a finite element analysis.

Polyaluminocarbosilane was synthesized by direct reaction of polydimethylsilane with aluminum(Ⅲ)-acetylacetonate in the presence of zeolite catalyst. A fraction of higher molecular weight polycarbosilane was formed due to the binding of aluminium acetylacetonate radicals with the polycarbosilane backbone. Small amount of Si-O-Si bond was observed in the as-prepared polyaluminocarbosilane as the result. Polyaluminocarbosilane fiber was obtained through a melt spinning and was pyrolyzed and sintered into SiC fiber from 1200~2000℃ under a controlled atmosphere. The nucleation and growth of β-SiC grains between 1400 - 1600℃ are accompanied with nano pores formation and residual carbon generation. Above 1800℃, SiC fiber could be sintered to give a fully crystallized β-SiC with some α-SiC.

Polycarbosilane is the most typical polymeric precursor for SiC ceramic. In this study, liquid type polycarbosilane was synthesized from polydimethylsilane in the presence of solid acid catalyst at 350oC. The molecular weights of the polycarbosilane were ranged between 350 and 530. Synthesized polycarbosilane was characterized with 29Si Solid NMR, FT-IR and GPC analysis. The synthesized polycarbosilane can be used as a good organometallic precursor for SiC coating via chemical vapor deposition or spin coating.

Four kinds of raw C/C composites with a density between 1.25~1.66g/㎤ were used in order to investigate the effect of the initial porosity of C/C composites on mechanical properties of liquid silicon infiltrated C/SiC composites. The microstructure observation, image analysis and flexural strength test of the composites were performed. The density and microstructural changes with the variation of the initial porosity was discussed in the terms of the infiltration behavior of liquid silicon and the reaction between liquid silicon and matrix carbon.

An exact lifetime extrapolation models of ZrO2-Al2O3-ZrO2 (ZAZ) stack capacitor with metal-insulator-metal (MIM) structure was studied in this paper. From the extensive long-term test result (~ 7.5 months) it was found that the power-law model is suitable as a exact lifetime extrapolation model for ZAZ dielectric reliability.