共查询到19条相似文献,搜索用时 156 毫秒
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根据Si-C-O-N系统的相稳定性计算,绘制了于平衡状态下相稳定性与N2分压和O2分压以及相稳定性与N2分压和SiO分压的关系图,发展了以气态SiO与碳纤维反应将碳纤维转变为SiC纤维,以及气态SiO与CO反应于碳纤维上形成SiC涂层的新方法。本文介绍这两种方法的工艺原理和主要实验结果。 相似文献
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对Si-C-O-N系统进行了平衡状态下的相稳定性计算,绘制了在1473K和1573K下的Si3N4、SiC、Si2N2O和SiO2相稳定性与N2分压和O2分压的关系图以及N2分压和SiO分区的关系图,Si3N4/Si2N2O/SiC、SiO2/Si2N2O/SiC两个三固相平衡点与N2分压、O2分压和SiO分压以及温度的函数关系日。并以此确定C纤维-SiC纤维转变和C纤维上涂层SiC过程中,为获得稳定SiC相的气体分压。 相似文献
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利用EPMA和XRD的分析方法,研究了Si_3N_4-Al_2O_3-ZrO_2系陶瓷材料表面氧化层组成。结果表明,Si_3N_4-Al_2O_3-ZrO_2系陶瓷材料表面氧化层是由方石英相、ZrSiO_4相和含有Al_2O_3、CaO等的SiO_2玻璃相所组成,其中SiO_2玻璃相中Al_2O_3、CaO等的含量,随着氧化时间的增加而逐渐增加。 相似文献
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研究了ZrN在Si_3N_4-ZrO_2复相陶瓷中的形成及其对材料性能的影响,结果表明:在1.5MPaN2气压烧结条件下,ZrN的形成温度约为1600℃,提高N_2的压力有利于抑制ZrN的生成,以稳定的t-ZrO_2加Si_3N_4基体中,对抑制ZrN的生成有明显作用。当复相陶瓷中生成一定量的ZrN时,力学性能明显下降,而ZrO_2分布均匀且以t-ZrO_2,c-ZrO_2形式存在时,复相陶瓷具有较高的强度(740MPa)和断裂韧性(8.8MPa·m ̄(1/2))。 相似文献
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粘胶活性炭纤维的吸附性能及其孔结构表征 总被引:1,自引:0,他引:1
由化学药品磷酸盐催化处理的粘胶纤维在氮气气氛下于820℃下炭化,随后用水蒸汽活化制得粘胶活性炭纤维。采用液氮77.4K下的吸附测定了该纤维的吸附等温线和常温下的静态苯吸附量以研究其吸附性能,并对其孔结构诸如比表面积、孔容、微孔容等进行了表征。 相似文献
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碳纤维增强磷酸钙骨水泥复合材料 总被引:9,自引:2,他引:7
采用碳纤维为增强相以提高磷酸钙骨水泥的力学性能。利用硝酸液态氧化法对碳纤维进行表面处理。仿照天然骨的结构,将处理后的碳纤维均匀埋于材料的受力面。制得的碳长纤维增强磷酸钙骨水泥生物复合材料,其抗折强度为10.80MPa。同样制备条件下,加入未处理的碳纤维,复合材料的抗折强度为6.35MPa,未加碳纤维骨水泥材料的抗折强度为5.81MPa。因此,以碳纤维为增强相并经表面处理后,可大大提高与骨水泥之间的界面结合强度,从而有效传递载荷,得到的复合材料的力学性能显著提高。利用X射线衍射及扫描电镜对复合材料的水化产物及微观结构进行了检测。 相似文献
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分别列举了16种有代表性的高性能和多功能纤维,论述世界特种合成纤维在技术进步和新市场开拓方面的新发展,并分析、预测今后的市场需求,对我国高科技特种合成纤维的发展提出了意见和建议。 相似文献
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含氮沥青基活性炭纤维的制备 总被引:6,自引:1,他引:5
用不同比例的浓氨水与水的混合物使乙烯渣油沥青基炭纤维活化,得到不同氮含量的活性炭纤维PACF(NH3)。元素分析及XPS均表明通过该活化方法可在活性炭纤维表面引入含氮官能团。含氮官能团以两种类型存在于PACF(NHa)的表面,即类吡啶和/或类腈官能团和类酰胺和/或类胺官能团。其N2吸附等温线均为I型,表明了PACF(NH3)的微孔性。 相似文献
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Stability of Phases in the Si-C-N-O System 总被引:4,自引:0,他引:4
HARUE WADA MING-JONG WANG TSENG-YING TIEN 《Journal of the American Ceramic Society》1988,71(10):837-840
The stability of the phases in equilibrium is calculated for the Si-C-N-O system in order to analyze and predict the reactions in ceramic whisker formation and sintering of silicon nitride composites. Equilibria among SiC, Si3 N4 , Si2 N2 O, SiO2 , Si, and the gas phase are evaluated at different carbon activities, nitrogen pressures, and temperatures. Phase stability diagrams are constructed as a function of nitrogen and oxygen pressures for two levels of carbon activity. Silicon nitride becomes a stable phase with increasing nitrogen pressure or decreasing carbon activity and temperature, whereas silicon carbide becomes a dominant phase at lower nitrogen pressures or at higher temperatures when carbon activity is unity. The maximum sintering temperature of the SiC/Si3 N4 composite is higher with an elevated nitrogen pressure or a reduced carbon activity. 相似文献
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特种纤维的表面处理及发展趋势 总被引:2,自引:0,他引:2
围绕着用于增强树脂基体的碳纤维及凯芙拉(Kevlar)等特种纤维的表面处理方法,特别是具有工业价值与发展前途的阳极氧化法、低温等离子法以及接枝聚合法等进行了介绍,并且对各自的优缺点及处理效果进行了评价。在此基础上,对特种纤维的界面结合理论与表面处理方法的发展趋势进行了讨论。还对迄今为止的一些有关鉴定处理效果的表征方法进行了介绍和评价。 相似文献
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Three-dimensional braided carbon fiber-reinforced nylon composites (C3D/MCN) were prepared in order to investigate the influence of oxidation of carbon fibers on the tribological properties of the C3D/MCN composites. Friction and wear tests of the C3D/MCN composites with untreated and treated carbon fabric were conducted. The characteristics of the carbon fiber, the interface strength, the hardness, and the worn surface morphologies of the C3D/MCN composites were analyzed. The results show that the specific surface area of treated carbon fiber was far higher than that of untreated carbon fiber and there formed a functional group of -C=O on the carbon fiber surface after air oxidation. The oxidation of the carbon fibers improved the interface strength between the carbon fibers and the matrix and had little effect on the hardness of the composites. The friction coefficient and wear rate of C3D/MCN composites with oxidized carbon fibers were apparently lower than those with untreated carbon fibers. In conclusion, the oxidation of the fibers showed good effects on the improvement of the interface strength and the tribological properties of the composites. 相似文献
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Three-dimensional braided carbon fiber-reinforced nylon composites (C3D/MCN) were prepared in order to investigate the influence of oxidation of carbon fibers on the tribological properties of the C3D/MCN composites. Friction and wear tests of the C3D/MCN composites with untreated and treated carbon fabric were conducted. The characteristics of the carbon fiber, the interface strength, the hardness, and the worn surface morphologies of the C3D/MCN composites were analyzed. The results show that the specific surface area of treated carbon fiber was far higher than that of untreated carbon fiber and there formed a functional group of –C=O on the carbon fiber surface after air oxidation. The oxidation of the carbon fibers improved the interface strength between the carbon fibers and the matrix and had little effect on the hardness of the composites. The friction coefficient and wear rate of C3D/MCN composites with oxidized carbon fibers were apparently lower than those with untreated carbon fibers. In conclusion, the oxidation of the fibers showed good effects on the improvement of the interface strength and the tribological properties of the composites. 相似文献