炭/炭复合材料的抗氧化研究现状

介绍了目前提高C／C复合材料抗氧化能力的方法，简述了抗氧化涂层的制备方法，综述了抗氧化涂层的几种典型结构。提出了对于C／C复合材料高温氧化保护研究方向的一些看法，阐明了其发展趋势及前景。     

炭/炭复合材料抗氧化研究进展

C／C复合材料的高温氧化性能限制了其在高温领域的广泛应用。本文简要介绍了C／C复合材料的氧。化机理及两种主要的抗氧化技术，即抗氧化涂层技术和内部抗氧化技术，并就涂层的结构和发展趋势作了简要介绍。介绍了添加抑制剂磷和硼对C／C复合材料的高温氧化抑制，重点分析了将硼引入C／C复合材料的方法及硼在其中的接触氧化抑制和优先分配。对C／C复合材料的最新进展情况作了简要介绍，并对C／C复合材料高温抗氧化的研究方向提出自己的看法。     

基体改性剂含量对C/C复合材料抗氧化性能的影响

采用氧化烧蚀试验研究了改性剂硼玻璃含量对Ｃ／Ｃ复合材料抗氧化性能的影响,通过扫描电镜（ＳＥＭ）观察分析了其抗氧化机理。结果表明：随着改性剂硼玻璃含量的增加,基体改性Ｃ／Ｃ复合材料的显气孔率逐渐降低,抗氧化能力逐渐增强,当硼玻璃的含量超高９．０ｗｔ％后,Ｃ／Ｃ复合材料抗氧化能力的提高趋于平缓;在基体改性Ｃ／Ｃ复合材料的氧化过程中,改性剂硼玻璃起到了内外涂层的作用,使其抗氧化能力大大提高。     

炭／炭复合材料高温抗氧化研究的现状

对炭／炭复合材料的高温抗氧化研究现状进行了全面介绍,重点侧重于抗氧化涂层制备方法及研究的最新进展。在此基础上,提出了1650℃以上抗氧化涂层研究的新思路。     

人工神经网络用于炭/炭复合材料CVD SiC涂层的研究

炭／炭复合材料抗氧化涂层是该材料可否用于高温结构件的关键。将人工神经网络用于ＣＶＤＳｉＣ抗氧化涂层的建模,试图解决该过程影响因素复杂、数学模型难于建立、无法对整个过程进行有效预测和控制的问题。初步探讨表明,采用人工神经网络建模,可以比较确切与全面地反映ＣＶＤＳｉＣ涂层过程的影响因素和内在规律,预测的工艺参数与沉积速率的关系同实验结果吻合较好,由此证实了将人工神经网络应用于抗氧化涂层制备系统是可行的     

炭/炭复合材料MoSi2/SiC抗氧化涂层的研究

采用包埋法制备C／C复合材料抗氧化MoSi2／SiC梯度涂层，同时对抗氧化涂层的形成、组织结构以及抗氧化性能与渗料的关系和抗氧化机理进行了研究。结果表明：采用包埋法制备的C／C复合材料抗氧化MoSi2／SiC梯度涂层致密，但有少量裂纹，涂层有良好的抗氧化效果。当Si与SiC保持一定的比例时，渗料中MoSi2的含量为50％时，涂层具有最好的抗氧化效果；当MoSi2与SiC保持一定的比例时，渗料中Si的含量为20％时，涂层具有最好的抗氧化效果。     

炭／陶复合材料的研究

采用高温热压法，制备了炭／Ｂ．ｃ，炭／金属钛及炭／Ｂ４Ｃ／金属钛三种炭／陶复合材料。着重研究了Ｂ４Ｃ、Ｔｉ的掺杂量对复合材料抗氧化能力的影响。结果表明，随着掺杂量的增加，复合材料的抗氧化能力提高。其中Ｂ４Ｃ的影响更显著。且炭、Ｂ４Ｃ、Ｔｉ三组份炭陶复合材料的抗氧化性较双组份复合材料更好一些。     

炭/炭复合刹车材料的防氧化技术研究进展

从炭／炭复合材料氧化特点、抗氧化要求出发，综述了基体改性技术和涂层技术，对炭／炭复合材料防氧化研究进展进行了详细的介绍，提出了对其高温抗氧化研究方向的一些观点。     

C／C复合材料抗氧化研究现状

结合国内外近几年研究报道,综述了C／C复合材料抗氧化方法,对各种涂层系统进行评述。文章最后展望了C／C复合材料高温抗氧化保护的研究方向。     

炭/炭复合材料抗氧化研究现状

总结了炭/炭复合材料抗氧化研究现状,重点介绍了抗氧化涂层的制备方法,包括包埋浸渍法、化学气相沉积(CVD)、溶胶-凝胶法(Sol-Gel)和水热电沉积法以及近几年针对抗氧化涂层开裂问题各国学者的最新研究成果。提出了炭/炭复合材料抗氧化研究今后努力的方向。     

Oxidation Behavior of Liquid-Phase Sintered Silicon Carbide with Aluminum Nitride and Rare-Earth Oxides (Re2O3, where Re = Y, Er, Yb)

Silicon carbide (SiC) ceramics have been fabricated by hot-pressing and subsequent annealing under pressure with aluminum nitride (AlN) and rare-earth oxides (Y₂O₃, Er₂O₃, and Yb₂O₃) as sintering additives. The oxidation behavior of the SiC ceramics in air was characterized and compared with that of the SiC ceramics with yttrium–aluminum–garnet (YAG) and Al₂O₃–Y₂O₃–CaO (AYC). All SiC ceramics investigated herein showed a parabolic weight gain with oxidation time at 1400°C. The SiC ceramics sintered with AlN and rare-earth oxides showed superior oxidation resistance to those with YAG and Al₂O₃–Y₂O₃–CaO. SiC ceramics with AlN and Yb₂O₃ showed the best oxidation resistance of 0.4748 mg/cm² after oxidation at 1400°C for 192 h. The minimization of aluminum in the sintering additives was postulated as the prime factor contributing to the superior oxidation resistance of the resulting ceramics. A small cationic radius of rare-earth oxides, dissolution of nitrogen to the intergranular glassy film, and formation of disilicate crystalline phase as an oxidation product could also contribute to the superior oxidation resistance.     

Oxidation mechanisms of SiC-fiber–reinforced Si eutectic alloy matrix composites at elevated temperatures

SiC-fiber–reinforced binary Si eutectic alloy composites have been developed for aerospace applications using the melt infiltration method. In this study, the oxidation mechanisms of various binary Si eutectic alloys were evaluated at elevated temperatures. We suggest that the oxidation resistance of eutectic alloys could be predicted using the Gibbs energy change for the oxidation reaction. Based on these calculations, eutectic alloys of Si-16at%Ti, Si-17at%Cr, Si-22at%Co, Si-38at%Co, and Si-27at%Fe were prepared. These alloys produced uniform SiO₂ layers and showed the same oxidation resistance as Si at 1000°C under humid conditions. Therefore, SiC composites using Si alloys with excellent oxidation resistance can be predicted using thermodynamic calculations.     

Isothermal and cyclic oxidation behavior of a sandwiched coating for C/C composites

A ZrC–SiC/TiC–SiC/SiC sandwich-structured coating is prepared on a C/C composite by pack cementation methods. The microstructures of this coating are characterized by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and the oxidation resistance is investigated by performing an oxidation test at 1773 K and a cyclic oxidation test. The results show that the mass losses are 7.4% and 3.8% after oxidation for 144 h and 40 cycles, respectively. The sandwich structure relaxes, releases the thermal stress caused by the mismatch in the coefficients of thermal expansion, and absorbs energy to prevent the initiation and propagation of cracks. The ZrC–SiC/TiC–SiC/SiC coating exhibits good isothermal oxidation resistance and excellent cyclic oxidation protection properties.     

C/C复合刹车材料及防氧化技术研究进展

介绍了Ｃ／Ｃ复合刹车材料的发展进程,国际上主要的飞机刹车机轮公司Ｃ／Ｃ复合材料及防氧化涂料的生产技术和工艺特点,Ｃ／Ｃ复合刹车材料的特性以及国内Ｃ／Ｃ复合刹车材料制备和防氧化技术的部分情况。     

Oxidation Behavior from Room Temperature to 1500°C of 3D-C/SiC Composites with Different Coatings

A carbon-fiber-reinforced silicon carbide composite (3D-C/SiC) was prepared by chemical vapor infiltration. A SiC and SiC/Si-Zr coating were deposited on the composite to investigate the effect of different coatings on the oxidation behavior of 3D-C/SiC composites. The 3D-C/SiC(SiC/Si-Zr) composite decreased in weight below 1000°C and increased in weight above 1000°C. With an increasing oxidation time, the weight loss increased greatly and the weight gain increased little. The 3D-C/SiC(SiC) composite always decreased in weight over the full temperature range. With an increasing oxidation time, the weight loss increased rapidly below 1000°C and reached its minimum value at 1400°C. The 3D-C/SiC(SiC/Si-Zr) composite had a higher oxidation resistance above 1000°C, and the 3D-C/SiC(SiC) composite had a higher oxidation resistance below 1000°C. The wider the coating cracks, the larger the maximum weight loss and the lower the temperature corresponding to the maximum weight loss. With an increasing oxidation time, the activation energy of the 3D-C/SiC(SiC/Si-Zr) composite increased from 96 to 138 kJ/mol, and the 3D-C/SiC(SiC) composite increased from 130 to 180 kJ/mol.     

Borate treatment of carbon fibers and carbon/carbon composites for improved oxidation resistance

Carbon fibers and carbon/carbon composites have been treated with borate additives and then cured at 500–600°C to produce a continuous film of boron oxide on all exposed surfaces.This treatment has been found to be highly effective in retarding oxidation of the carbonaceous substrate for extended periods in flowing air at temperatures up to 1000°C. At higher temperatures, and in the presence of water vapor, borate species were appreciably volatile and the oxidation protection provided by the coatings was less effective.     

固渗+EB-PVD法制备炭/炭复合材料防氧化复合涂层研究

制备出了SiC/SiC-Al2O3-Y2O3炭/炭复合材料防氧化复合涂层,该复合涂层的内层SiC基涂层采用料浆固渗法制备,SiC-Al2O3-Y2O3外层涂层采用大功率电子束物理气相沉积法。研究表明,电子束物理气相沉积法能达到较好的沉积效果,在制备过程中形成了柱状晶结构的涂层,使得涂层具有更高的应变容限,涂层非常均匀致密。用SEM、XPS和EDS等分析方法分析了涂层的防氧化机理。结果表明:在制备过程和氧化过程中,涂层内会发生复杂的物理和化学变化,生成硅酸盐氧化物,显示出电子束物理气相沉积法在制备炭/炭复合材料防氧化涂层方面独特的优势。