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炭基体结构状态对C/C复合材料抗烧蚀性能的影响 总被引:12,自引:2,他引:12
碳基体在C/C复合材料的组成中占有很大的比重,因此炭基体不同的结构状态往往对C/C复合材料的各项性能有显著的影响。本文利用不同的原料和加工工艺制备出了三种具有不同炭基体的C/C复合材料,这三种碳基体分别是热解炭,沥青炭以及解热炭-树脂炭混合炭基体。对这三种材料多项性能的测试结果表明,炭基体的结构状态如石墨化度,炭片层结构的取向度的不同对C/C复合材料的各项性能均有显著的影响;基本趋势是C/C材料的石墨化度越高,材料的导电性能,导热性能以及抗烧蚀性能越好,压缩强度越低。三种炭基体中沥青炭基体沿纤维轴向的取向度最低,其抗烧蚀性能最差。 相似文献
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碳/碳(C/C)复合材料是以碳为基体,碳纤维增强的复合材料,具有高比强度、高比模量、耐高温、耐腐蚀、耐疲劳、抗蠕变、导电、传热和膨胀系数小等一系列优异性能,既可作为结构材料承载重荷,又可作为功能材料发挥作用。同时,碳/碳(C/C)复合材料是一种能在超高温条件下工作的高温结构材料,所以在航空航天领域具有广阔的应用前景。本文综述了碳/碳(C/C)复合材料的制备相应力学、热学性能,化学性能和其在各领域的应用进展。 相似文献
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C/C喉衬材料的研究与发展 总被引:11,自引:0,他引:11
C/C复合材料是高技术新材料,1972年法国的2DC/C喉衬材料参与型号首飞成功以来,极大地推动了喷管材料的更新换代,其C/C材料与工艺研究经过了四代发展历程,已成为当今SRM喉衬的首, SRM喉衬中的应用取得了重大成就。 相似文献
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最近发展起来的SiC纤维复合涂层,也就是SiC/SiC层与化学气相沉积(CVD)SiC结合形成复合涂层,已能够在高温下提高C/C复合材料的抗氧化性。形成的SiC纤维复合涂层约300μm厚,生产时先将SiC毡覆盖在3D-C/C基体材料上,然后浸渍一种碳粉与硅粉均匀分散的料浆进行化学气要沉积。通过化学气相沉积(CVD)过程,在复合材料上形成致密的涂层。在CO2-H2O-N2组成的混合气体(CO2 9%、N273%、H2O18%),1700℃下进行5h氧化实验,结果发现有SiC毡增强复合涂层比没有SiC毡增强复合材料失重率低。SiC纤维毡复合涂层由双层结构组成,里层是多气孔的SiC/SiC纤维层,外层为致密的SiC涂层。由于SiC/SiC纤维层热膨胀系数介于C/C复合基体材料与CVD-SiC涂层之间,因此,SiC/SiC中间层在复合材料中起了重要作用,从而由于热膨胀系数不同产生的热应力致使涂层开裂降低到最低程度。涂层试样氧化后,采用缓冲冲床(MSP)测试其残余强度。MSP测试结果表明氧化后C/C复合材料强度值呈发散性,从纤维折断面看有z轴方向分布纤维存在。然而,这种方法仅适用于测试小尺寸试样。从这篇论文中,可看出涂层后的C/C复合材料有高的抗氧化性,其氧化后仍能保持高的残余强度。 相似文献
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多晶硅用直拉法(CZ)或磁场直拉法(MCZ)拉制成单晶硅棒。晶体生长炉热场零件中的石墨发热体、坩埚等在机械应力和热应力的综合作用下发生变形或损坏造成失效,更换频繁。选用纯度高的炭纤维制成待制件的多孔坯体,经过增密、纯化处理制成炭/炭复合材料坩埚。试制的两体12″炭/炭复合材料坩埚进行了工业性试验。炭/炭复合材料机械强度高、耐热冲击性能和化学稳定性好,其使用寿命大大高于高纯石墨坩埚。两体的连接止口的氧化侵蚀限制了坩埚的使用寿命。单晶硅设备的大型化、炭/炭复合材料势必成为晶体生长炉热场零件的必选材料。 相似文献
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C/C复合刹车材料及防氧化技术研究进展 总被引:3,自引:0,他引:3
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。 相似文献
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在M2000型摩擦机上,与表面Cr的40Cr钢配副,测试两种C/C复合材料不同密度试样的摩擦磨损性能。结果表明:随载荷增加,在两种材料中,低密度试样的摩擦系数较高且波动幅度大,1.8g/cm3以上试样的摩擦系数、波动幅度较低。其中A、B材料低密度试样摩擦系数波动幅度最大,分别可达0.02、0.038,而高密度试样的分别为0.012、0.012。随时间延长,A材料低密度试样摩擦系数升高,高密度试样的保持稳定;B材料低密度试样的变化不规律,高密度试样能基本保持稳定。SEM观察表明,随密度增加,材料B的磨损表面由粗糙、充满磨屑逐渐向较完整、致密的磨损表面转变。 相似文献
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Ze Yu Wang Man Ni Li Jin Ba Qiang Ma Zeng Qi Fan Jing Huang Lin Zheng Xiang Zhong Jun Lei Qi Jian Cao Ji Cai Feng 《Journal of the European Ceramic Society》2018,38(4):1059-1068
Brazing C/C composite to Nb is often associated with the problem of high residual stress, resulting in low-strength joints. To overcome these problems, here we carried out a simple polymer carbonization process to acquire uniform carbon-covered Cu foam composite interlayer, which was subsequently used for soundly brazing C/C composite and Nb with the assembly of C/C composite/Ag-Cu-Ti foil/C-Cu foam/Ag-Cu-Ti foil/Nb. Microstructure and mechanical properties of the joints were well investigated. The carbonization reacted with Ti elements, forming uniformly distributed in-situ TiC nano-flakes in the joint seam by virtue of the porous Cu foam skeleton. Results present that the in-situ TiC nano-flakes not only greatly reduced the thermal expansion coefficient but also effectively impeded the Cu solid solutions agglomeration. The average shear strength of the joint brazed with 3% C-Cu (wt.%) foam interlayer reached ~52.8 MPa with the brazing temperature of 880 °C for 10 min. 相似文献
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《Ceramics International》2022,48(13):18246-18256
C/C composite is widely used in aerospace due to excellent high temperature mechanical properties. Improving its ablation resistance has become the focus of attention. Due to anisotropy of composite materials, the difference of thermal conductivity and thermal expansion coefficient between fiber and matrix, surface morphologies affect ablation performance greatly. In particular, fiber exposed length (FEL) and crack had a significant impact on its ablation resistance. Therefore, this paper constructed a FEL theoretical model based on machining damage, and verified that the error of the modified model was within 12 % through experiments. Meanwhile, improvement effect of rotary ultrasonic machining (RUM) was clarified. It is found that RUM reduced FEL by 15%~38% in all fiber angles and decreased the crack pores on machined surface. Then, oxyacetylene ablation experiments on C/C composite surface under conventional machining (CM) and RUM were carried out. The results showed that RUM surface had better ablation resistance, and interface ablation and porosity decreased significantly. 相似文献
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针对同批炭/炭复合材料力学性能测试结果相差较大的情况,从取样、试样加工过程和工艺试验研究入手,通过分析其力学性能测试结果,对加工参数、加工方法对炭/炭复合材料力学性能测试的影响程度进行了研究,结合对所加工试样的表观质量分析,系统地探讨各种参数的影响,给出适合炭/炭复合材料试样加工的最优切削参数,并给出试样界面尺寸的公差控制范围,有效地降低了炭/炭复合材料试样力学性能测试的偏差。 相似文献
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《Ceramics International》2016,42(15):17174-17178
Reactive melt infiltration is a fast and economical fabrication process for high performance C/C-SiC composite. In order to help understanding reactive melt infiltration production of C/C-SiC composite by liquid silicon, wetting and infiltration of the porous C/C composite preform by liquid silicon were investigated using a sessile drop technique. The contact angle decreased with the increase of time while the drop base diameter increased. According to the variation of drop base diameter and contact angle as a function of time, four different stages corresponding to the interfacial reaction and infiltration of liquid silicon were identified during wetting of the porous C/C composite preform by the liquid silicon. The infiltration height based on wetting curve linearly increased with time, much smaller than that calculated according to Washburn equation, which strongly indicated the reaction control of silicon infiltration. 相似文献
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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. 相似文献