新型炭材料
论述了两种可溶有机组分含量(8w/%,25w/%)的柴油机油烟的燃烧机理.采用加热速率5℃/min～20℃/min非等温条件下的热重分析(TGA),考察了其在空气中的燃烧.应用Ozawa-Flynn-Wall方法,研究了析出物质的数据资料,并由复变非线性回归方法获得了各动力学参数.两种油烟的析出可根据三段机理予以模定,即:(1)可溶有机组分(SOF)的蒸发,(2)SOF热裂解,(3)炭基质燃烧.由于两种油烟所得的动力学参数非常近似,表明SOF含量对基质燃烧的影响极其有限.
关键词:
柴油机油烟
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热重分析
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燃烧
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动力学
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可溶有机组分
Yanhua LI
材料科学技术（英文）
SiCf/Ti-6Al-4V composites were fabricated by the powder-coated fiber method. The precursor fiber was prepared under the optimized parameter, and the composites were made using the vacuum hot pressure method. The influence of heat exposure time on products of the interfacial reaction was investigated using scanning electron microscope (SEM) and analytical transmission electron microscope (TEM) with energy dispersive spectrometer (EDS). The main products are TiC and Ti5Si3 after vacuum exposing the samples at 700℃ for 50 h. The growth dynamics of interfacial reaction products was analyzed quantitatively, which fitted the parabola rule. The activity energy of the reaction was 252 kJ•mol-1.
关键词:
Powder coated fiber
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Lin LI
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B.C.De Cooman
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P.Wollants
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Yanlin HE
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Xiaodong ZHOU
材料科学技术（英文）
With the sublattice model, equilibrium compositions of ferrite (α) and austenite (γ ) phases, as well as the volume percent of austenite (γ) at 780℃ in different TRIP steels were calculated. Concentration profiles of carbon, Mn, Al and Si in the steels were also estimated under the lattice fixed frame of reference so as to understand the complex mechanical behavior of TRIP steels after different isothermal bainitic transformation treatments. The effect of Si and Mn on transformation induced plasticity (TRIP) was discussed according to thermodynamic and kinetic analyses. It is recognized that Al also induces phase transformation in the steels but its TRIP effect is not as strong as that of Si.
关键词:
Equilibrium composition
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