热解炭涂层技术是目前解决单晶硅生产用炭/炭热场材料高温侵蚀的有效方法之一,本文介绍了热解炭涂层的制备技术及优缺点,综述了热解炭涂层在炭/炭热场材料领域的应用及研究进展,对炭/炭热场材料高温抗侵蚀涂层提出了建议和发展方向.

碳化硅涂层是目前解决单晶硅生产用炭/炭热场材料高温侵蚀的有效手段之一,本文介绍了碳化硅涂层的制备技术及优缺点,综述了碳化硅涂层在炭/炭热场材料领域的应用及研究进展,对炭/炭热场材料高温抗侵蚀涂层的发展提出了建议和方向.

采用反应熔渗工艺(RMI)快速制备了不同碳化硅含量的C/C-SiC复合材料,通过氧-乙炔烧蚀试验,测试了材料的烧蚀性能.利用SEM/EDS表征了复合材料烧蚀后的表面形貌和成分,分析了碳化硅含量对复合材料烧蚀性能的影响.结果表明,随着基体中碳化硅含量的提高,烧蚀过程中生成的二氧化硅保护膜更加致密,导致C/C-SiC复合材料的烧蚀率逐渐降低.在此基础上,利用优化工艺制备了密度均匀的大尺寸C/C-SiC构件,经过地面热试车考核,构件接近零烧蚀,满足发动机热试车的应用.

Solid rocket motors using five different C/C composites (radially woven 4D C/C, axially woven 4D C/C, integral felt C/C, needle felt C/C and punctured 3D C/C) and two kinds of graphite (T705 graphite and an anisotropic pyrolytic graphite with a density of 2. 18 g/cm(3), a porosity of 1% and graphene layers perpendicular to throat surface) as the throat inserts were propelled by hydroxyl terminated polybutadiene or a high energy fuel to test the ablation rates of the throat inserts. The effect of nozzle thermal environment (propellant type and combustion chamber pressure) on the ablation rates of the throat insert materials was investigated under identical conditions. Results show that the ablation rates of the carbon materials are closely related to the concentration of the oxidative gases (H2O and CO2) and the chamber pressure. The chamber pressure is of primary importance, and doubling it leads to an increase of ablation rates by 1. 8-2.6 times. The ablation rates using the hydroxyl terminated polybutadiene propellant are 51. 6% - 65. 1% higher than those using the high energy propellant because the concentration of oxidizing H2O in the former is 1. 26 times higher than that in the latter. The pyrolytic graphite has the lowest ablation rate followed by the integral felt C/C, needle felt C/C and axially woven 4D C/C. The radially woven 4D C/C has the highest rate, and the punctured 3D C/C and T705 graphite have similar ablation rates. The ablation rates of the five composites and two graphites made in China are similar or superior to the C/C composites and Graphnol graphite made in other countries.

Five kinds of carbon-carbon composites used in aerospace, aircraft, photovoltaics, powder metallurgy and high temperature furnaces are reviewed, whose preforms were fabricated by needle piercing, orthogonal three-direction weaving, radial weaving, axial weaving and puncture. The physical, mechanical, thermal, ablation, and wear properties and service life were compared with corresponding materials from overseas manufacturers. Correlations between the performance, type of preform and carbon matrix, and interfacial bonding state was obtained. These analyses and comparisons can lay a foundation for the construction of a database-sharing platform for C/C composites in engineering applications. Research efforts need to be focused on the fine structure and gradient design of preforms and the optimum combination of different carbon matrices for the improvement of C/C composites.

Two-dimensional carbon fiber reinforced resin polymer(CFRP)composites with graphite filler added into resin were prepared,which were further pyrolyzed under different temperatures and infiltrated liquid silicon to fabricate C/C-SiC composites. The effect of graphite filler on microstructure,capillary infiltration behavior and flexural properties were investigated.The results show that interface between fiber bounders of C/C composites with graphite filler has no micro-delamination,and bending behavior of C/C composites with graphite filler presents no significant difference compared with C/C materials without graphite filler.However,cap-illary infiltration mass rates of C/C composites are reduced due to graphite filler.Pyrolysis temperature has significant effect on po-rosity,bending strength as well as capillary infiltration behavior of C/C composites. Flexural strength of C/C-SiC composites pre-pared by above mentioned different C/C composites,is 120~130 MPa.

The paper evaluates the basic material properties including physical,mechanical and thermal properties, then analy?ses the application performance such as thermal shock resistance and ablation resistance of the first generation high?strength graph?ite,the second generation high?density and high?strength graphite and the third generation isotropy graphite,which have been suc?cessfully applied in throat insert of solid rocket motor in China.Analytical comparison of material properties and functions between a?bove?mentioned graphite and foreign similar graphite has been conducted to lay a foundation to establish a database of throat?insert?used graphite material.The correlation among tensile strength,thermal conductivity,elasticity modulus,coefficient thermal expansion and thermal shock resistance has been revealed.The paper indicates that properly increasing the granularity in the formula,raising graphitization temperature and properly controlling the density range of graphite constitute are the major improving directions to en?hance the overall performance of isotropy graphite.

Pyrolytic carbon coating was fabricated using ethanol as precursor on pitch based carbon monofilament by cold wall chemical vapor deposition. Scanning electron microscopy and Raman spectroscopic analysis were used for the characterization of microstructure of samples. The results indicate that the deposition temperature is favor for the orientation of microstructure and the growth of crystal simultaneously. On proper fabrication conditions, the pyrolytic carbon coating appears a Raman spectrum that the I-2700/I-G is about 2.23, which indicates that the coating has narrow crystal size distribution and little defect.

采用6K炭纤维无纬布/网胎交替叠层及12K炭纤维无纬布/网胎交替叠层,在针刺工艺,致密化、热处理工艺完全相同的情况下,制备了密度为1.8g/cm3的热解炭/树脂炭双元基体的两种C/C复合材料产品,考察了针刺预制体结构单元对C/C复合材料性能的影响.结果表明,两种C/C复合材料的热学(垂直方向导热系数)、电学性能及石墨化度基本相当;而针刺6K炭纤维无纬布/网胎预制体C/C复合材料的拉伸、弯曲、压缩、层间剪切强度分别为127MPa,189MPa,263MPa,24.6MPa;其平行方向导热系数为54.6W/m·K,比常规针刺12K炭纤维无纬布/网胎预制体C/C复合材料相应提高了38％,32.2％,32.8％,38.9％,21％,彰显了细化针刺预制体结构单元对C/C复合材料力学性能的显著影响.

利用熔盐反应法在由NaCl和KCl组成的混合盐体系中成功地在炭/炭复合材料表面制备出TiC涂层.使用XRD和SEM等方法对涂层的晶相组成和微观形貌进行了分析和观察.研究了涂层试样从室温到1 200℃范围内的氧化行为以及在800℃静态空气中的氧化失重情况.结果表明:在850～950℃内能够在炭/炭复合材料表面制备TiC涂层,在950℃制备的TiC涂层中还含有AlCTi2.随着反应温度的升高,涂层的厚度增加,涂层颗粒尺寸增大.在950 ℃保温6h制备的涂层完整均匀,与基体的结合良好,但是在局部区域仍有微小的裂纹存在.高温生成的AlCTi2在一定程度上提高了涂层试样的抗氧化性,涂层后炭/炭复合材料的起始氧化失重温度从原来的450℃升高到800℃左右,氧化12h的失重率为5.09％.

通过对密度1.8 g/cm3针刺炭纤维炭/炭复合材料喉衬中炭纤维、热解炭、树脂炭体积分数优化设计和控制,并匹配以大装炉量的三路进气、多沉积室均热法CVI与高效的树脂浸渍/炭化相结合致密工艺,2 600℃热处理,制备了低成本、低开孔率、低烧蚀率的针刺炭纤维炭/炭复合材料喉衬.其1 800℃的拉伸强度径向达到109.8 MPa,轴向达到21.3 MPa,在火箭弹高压强固体火箭发动机中的烧蚀率仅为0.05～0.09 mm/s.并揭示了炭纤维、热解炭、树脂炭互为补充优化组合及致密工艺与材料低开孔率的关联.为火箭弹高压强固体火箭发动机增添了一种低烧蚀率高可靠的喉衬材料.

研制了一种以磷酸盐涂层和陶瓷涂层相结合的新型复合防氧化涂层,并针对不同的烧结温度对这种复合涂层的防氧化性能进行了研究.结果表明:在700℃静态氧化30 h后,800℃烧结的复合涂层试样的氧化失重率最小,为0.99％;经过900℃,3 min(≒)室温,2min 30次和1 100℃,3 min(≒)室温,2 min 10次连续热震后,其氧化失重率仅为0.31％,氧化速率为1.34×10-7g·cm-2·s-1.SEM观察结果显示不同烧结温度制备的涂层表面微观形貌明显不同,800℃烧结的涂层表面完整致密,氧化后涂层仍然保持完好,没有脱落,说明该涂层与炭基体的结合性能以及热稳定性能良好,适合作为飞机炭刹车副的防氧化涂料.

Four preparation methods for low-density C/C(LD-C/C)insulation materials were employed,and how the reforming structure,carbon matrix,heat treatment temperature and density of the materials affect the thermal conductivity of the LD-C/C insulation material were investigated.The results show that the thermal conductivity of the needle-punched felt overall structure is the highest,that of the thin felt adhesive structure is the lowest,and those of the thick felt adhesive structure and the thin felt with thick felt alternately overlay structure are intermediate.Furthermore,the thermal conductivity of the resin carbon matrix C/C insulation is lower than that of the pyro-carbon matrix C/C insulation.The thermal conductivity of thin felt adhesive structure C/C insulation increases with the increase in heat treatment temperature.Similarly,the thermal conductivity of low density C/C insulation material is enhanced withincreasing density.

研究了两种炭/炭复合材料液相致密用高效、安全的浸渍剂.一种为混合树脂体系,即氨酚醛树脂与树脂B混合且不添加其他任何固化剂;一种为利用新型固化剂C取代磷酸作为糠酮树脂的固化剂.结果表明,混合树脂与纯氨酚醛树脂浸渍剂相比较,其残炭率提高约10％;当混合树脂体系中树脂B的质量分数为30％～50％时,具有较好的残炭率;新型固化剂C作为糠酮树脂固化剂时,其残炭率与磷酸作为固化剂时相当,且安全性更高,具有取代磷酸作为糠酮树脂固化剂的可能性.

The invention discloses a carbon/carbon composite material crucible preparation method comprising the steps that: 1, a carbon fiber perform is densified; 2, the densified carbon fiber perform is subjected to liquid-phase silicon infiltration, such that a carbon/silicon carbide composite material is obtained; and 3, according to the shape and size of the needed crucible, the carbon/silicon carbide composite material is subjected to mechanical processing, such that the carbon/silicon carbide composite material crucible is obtained. According to the invention, a chemical vapor infiltration process is combined with a resin liquid-phase densification process, and the carbon/silicon carbide composite material is densified, such that preparation period is shortened, and production cost is effectively reduced. Also, with a pyrolytic carbon substrate obtained with the chemical vapor infiltration process, carbon fiber in the perform can be effectively protected. Resin carbon obtained in the resin liquid-phase densification process, carbon source is provided for subsequent liquid-phase silicon infiltration process. One-time forming is carried out with the liquid-phase silicon infiltration process, such that preparation period is short, and preparation cost is greatly reduced. The service life of the prepared crucible is greatly improved.

本文通过对比分析几种常用的飞机炭刹车盘钢夹结构,提出了用于A320系列飞机炭刹车盘的改进钢夹结构,有效地减少了由于钢夹损坏造成未磨损到寿的炭刹车盘不能继续使用的情况,提高了炭刹车盘使用的可靠性.

20世纪90年代以来,世界各国均致力于开发C/C复合材料的工程化致密技术,以达到降低成本,拓展民用领域的目的.经过20多年的艰辛攻关,在快速化学气相渗透和新型液相浸渍炭化致密技术方面取得了长足的进步,为拓展C/C复合材料在民用领域的应用,奠定了良好的基础.

研究了炭/炭硬化保温材料的两种表面涂层方法.对封孔后的低密度材料进行SEM分析,对硅粉涂层与炭界面进行EDS和XRD分析,然后,(360±10)℃空气中进行氧化烧蚀试验.结果表明:封孔石墨颗粒大小对低密度炭/炭保温材料的封孔效果有很大的关系,TC-200涂层效果致密效果好；硅粉涂层与炭本体界面在1 600℃处理后形成碳化硅致密层,对低密度材料起到很好的防护作用.

针对高温处理炉使用环境气氛,采用针刺无纬布、网胎交替叠层的预制体,优化组合预制体中结构单元,经气相、液相相结合的致密方法增密后,经高于使用温度高温处理制得炭/炭复合材料吊具,并进行了力学、热学性能检测和微观形貌分析.经校核所研制炭/炭复合材料吊具达到负载2吨能力(安全系数2),可与产品一起经历1 400℃～2 600℃高温处理过程,解决目前高温处理无随炉吊装工具的问题,实现在炉外装出产品整体吊装操作.

The tests for friction coefficient, average moment and wear ratio of carbon brake discs such as ChaomaB757, A320 and DunlopB757, Messier-Bugatti A320Sepcarb®IIIOR, have been carried out under the condition of field operation on airplane at different brake velocity/pressure by HJDS-IIDynamometer. The results show that the energy and moment of the four types of carbon brake discs increase with increasing braking velocity/pressure. The friction coefficient shows lower energy peak property, and with increasing brake velocity/pressure, the friction coefficient decreases. ChaomaB757, A320 carbon brakes present two characteristics: the braking pressure is 25% lower and the friction coefficient is 25%-29% higher than those of the abroad ones; the longest life-span on airplane of B757 is in the range of 2823 to 3289 times of landing, which is equivalent to abroad ones. The aircraft brake discs shows the excellent characteristic of wear ratio.