Nanoscale powder of SiO2/Al2O3/TiO2 composite was prepared by sol-gel method. Microstructure and morphology of the obtained samples were characterized by infrared （IR）, X-ray diffraction （XRD） analysis and transmi...Nanoscale powder of SiO2/Al2O3/TiO2 composite was prepared by sol-gel method. Microstructure and morphology of the obtained samples were characterized by infrared （IR）, X-ray diffraction （XRD） analysis and transmission electron microscopy （TEM）. It is proved that infrared absorbing peaks of the samples are in waveband range of 1300-400 cm^-1, and the peak shape changes with their component. Mechanism of the infrared peak＇s positions and shapes which changes with the size and morphology of the prepared nano-particles has been tentatively discussed.展开更多
The mechanical behavior of three-dimensional integral braided carbon-carbon composites (C/C) has been explored under unconventional fatigue loading, and a series of special experimental phenomena were observed. In thi...The mechanical behavior of three-dimensional integral braided carbon-carbon composites (C/C) has been explored under unconventional fatigue loading, and a series of special experimental phenomena were observed. In this present paper, one of these phenomena, the micro silk-like pleating of the pyrocarbon matrix, is discussed. With thermodynamic analysis, it is shown that small areas of high-temperature contribute to the micro-pleating formation. Moreover, slight friction between pyrocarbon laminates has been proven to produce the small high-temperature areas during cyclic tensile loading.展开更多
基金the Science Foundation of Yunnan Province under grant No.2001E0003Z.
文摘Nanoscale powder of SiO2/Al2O3/TiO2 composite was prepared by sol-gel method. Microstructure and morphology of the obtained samples were characterized by infrared （IR）, X-ray diffraction （XRD） analysis and transmission electron microscopy （TEM）. It is proved that infrared absorbing peaks of the samples are in waveband range of 1300-400 cm^-1, and the peak shape changes with their component. Mechanism of the infrared peak＇s positions and shapes which changes with the size and morphology of the prepared nano-particles has been tentatively discussed.
基金supported by the National Natural Science Foundation of China(Grant No.50072019)National Defense Science&Technology Fund(2000J12.5.3,HK0312).
文摘The mechanical behavior of three-dimensional integral braided carbon-carbon composites (C/C) has been explored under unconventional fatigue loading, and a series of special experimental phenomena were observed. In this present paper, one of these phenomena, the micro silk-like pleating of the pyrocarbon matrix, is discussed. With thermodynamic analysis, it is shown that small areas of high-temperature contribute to the micro-pleating formation. Moreover, slight friction between pyrocarbon laminates has been proven to produce the small high-temperature areas during cyclic tensile loading.
