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C/SiC/Si-Mo-Cr复合涂层碳/碳复合材料力学性能研究 总被引:4,自引:1,他引:3
采用包埋法和涂刷法在碳/碳复合材料表面制备了一种新型的C/SiC/Si-Mo-Cr复合高温抗氧化涂层. 借助XRD和SEM等测试手段对所制备复合涂层的微观结构进行了表征, 采用三点弯曲试验研究了涂层处理及热震试验对碳/碳复合材料力学性能的影响规律. 结果表明: 制备的多相涂层结构致密, 涂层后碳/碳复合材料弯曲强度有所增大, 断裂特征由假塑性向脆性转变. 涂层试样经1500℃至室温20次热震后, 涂层试样的弯曲强度降低, 塑性增强. 相似文献
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SiC/PyC复合涂层碳纤维微观结构及氧化行为研究 总被引:1,自引:0,他引:1
采用两步法在碳纤维表面制备了碳化硅/热解碳(SiC/PyC)复合涂层,PyC内涂层的制备采用等温化学气相渗透法,SiC外涂层的制备采用碳热还原法.借助X射线衍射、场发射扫描电镜、透射电镜分析了SiC/PyC复合涂层碳纤维的物相组成以及微观结构,利用热重分析研究了SiC/PyC复合涂层、PyC涂层以及无涂层碳纤维的氧化行为.结果表明,在碳纤维表面制备的SiC/PyC复合涂层连续致密、厚度均匀,PyC内涂层厚度约为200nm,SiC外涂层厚度约为160nm,SiC层中存在大量孪晶面高度有序的SiC孪晶.SiC/PyC复合涂层能够有效地改善碳纤维的抗氧化性能,较无涂层碳纤维起始氧化温度提高了近250℃. 相似文献
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碳/碳复合材料SiC/Al-Si涂层微观结构及抗氧化性能研究 总被引:1,自引:0,他引:1
采用料浆法在碳/碳复合材料碳化硅(SiC)内涂层表面制备了Al-Si合金外涂层,采用XRD和SEM分析了涂层的微观结构,并测试了带有SiC/Al-Si复合涂层的碳/碳复合材料试样在1500℃静态空气中的抗氧化性能.结果表明:Al-Si合金外涂层主要成分为Al3.21Si0.47,含有少量Al2O3;SiC/Al-Si复合涂层厚度约为120μm,无穿透性裂纹;SiC/Al-Si复合涂层的抗氧化性能明显优于单一SiC涂层,氧化17h后涂层试样的质量损失未超过5%. 相似文献
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为提高碳/碳复合材料抗氧化性能,以甲基三氯硅烷(MTS)为先驱体,利用低压化学气相沉积(LPCVD)技术在碳/碳复合材料表面制备SiC-MoSi2涂层,通过XRD和SEM分析了不同沉积温度下涂层结构、物相组成及其沉积机理。结果表明,沉积温度对涂层的成分、结构及致密度有较大影响,在1100~1250℃均可成功得到SiC-MoSi2涂层,1100℃所得涂层结构疏松多孔;1250℃制备的涂层中间部位孔隙较多,表层为致密SiC涂层;1150~1200℃之间可得到均匀致密、以MoSi2颗粒为分散相、以CVD-SiC为连续相的SiC-MoSi2双相陶瓷涂层。 相似文献
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以TiFe 粉和碳的前驱体(石油沥青) 为原料, 用前驱体碳化复合技术制备了Ti-Fe-C 反应喷涂复合粉末, 并采用普通火焰喷涂技术成功制备了TiC/ Fe 陶瓷金属复合涂层。研究了不同C/ Ti 原子比对反应火焰喷涂TiC/ Fe 复合涂层相组成、显微结构和硬度的影响。结果表明, 前驱体碳化复合技术制备的Ti-Fe-C 系反应喷涂复合粉末中C/ Ti 原子比是影响涂层相组成、显微结构和硬度的关键因素。C/ Ti 原子比不同, 涂层的相组成和硬度不同; 随着C/ Ti 原子比增大, 涂层中TiC 团聚富集区增大, 涂层的孔隙率也随之增大。 相似文献
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化学气相沉积碳化钛的热力学和动力学研究 总被引:7,自引:0,他引:7
对采用TiCl4-CH4-H2反应体系化学气相沉积碳化钛的反应热力学和成核热力学因素进行了分析,并在实验的基础上研究了不同沉积温度下化学气相沉积TiC过程的动力学特征,以及在不同的动力学控制机制下气相过饱和度的成核过程对TiC涂层的析出形态的影响。在沉积过程中,气相过饱和度和动力学控制机制是控制沉积物的成核过程和析出形态的决定因素。 相似文献
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运用激光熔覆技术修复受损的烟汽轮机叶片,在GH864镍基合金表面制备原位自生TiC颗粒增强Ni3(Si,Ti)金属间化合物复合涂层.利用扫描电镜、能谱分析仪、X射线衍射仪及显微硬度计研究了(Ti+C)的加入量对熔覆层组织及硬度的影响.研究表明:在优化的工艺参数下可获得宏观质量完好,无裂纹、气孔等缺陷,且与基体呈冶金结合的激光熔覆层,熔覆层由Ni(Si)、Ni3(Si,Ti)和TiC组成;当合金粉末中(Ti+C)的加入量为20%时熔覆层的硬度最高可达780Hv,是基体材料的2.4倍. 相似文献
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碳化钛/钛镍金属间化合物复合涂层相组织研究 总被引:1,自引:0,他引:1
利用钛粉、镍粉和胶体石墨,真空条件下通过反应钎涂技术在低碳钢基体上制备了与基体冶金结合的碳化钛/钛镍金属间化合物复合涂层。采用扫描电子显微镜、能谱仪、X射线衍射仪及硬度计,研究了涂层的相组成、组织结构和成分分布。涂层组织由NiTi2、NiTi、TiC和hcp Ti组成,而涂层界面由NiTi和少量的hcp Ti构成,并且TiC主要分布在涂层中层。涂层中的NiTi2、NiTi、TiC是在钎涂过程中原位反应合成的,而且TiC和NiTi的量随碳含量的增加而增加。涂层表面硬度达到85HR15N,但不随TiC和NiTi含量增加而增高。 相似文献
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Sen YANG Wenjin LIU Minlin ZHONG 《材料科学技术学报》2006,22(4):519-525
A Ni-base alloy composite coating reinforced with TiC particles of various shapes and sizes on medium carbon steel substrate was produced by multilayer laser cladding. The chemical compositions, microstructures and surface morphology of the cladded layer were analyzed using energy dispersive X-ray spectroscopy (EDX), scanning electron microscope (SEM), and X-ray diffractometry (XRD). The experimental results showed that an excellent metallurgical bonding between the coating and the substrate was obtained. The microstructure of the coating was mainly composed of γ-Ni dendrites, a small amount of CrB, Ni3B, M23C6 and dispersed TiC particles. Much more and larger TiC particles formed in the overlapping zone, which led to a slightly higher microhardness of this zone. The maximum microhardness of the coating was about HV0.21200. The effects of the laser processing parameters on the microstructures and properties of coating were also investigated. 相似文献
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I. Jouanny S. Jacques P. Weisbecker C. Labrugère M. Lahaye L. Maillé R. Pailler 《Journal of Materials Science》2010,45(24):6747-6756
TiC coatings were synthesised on NL202 Nicalon fibres through the treatment of a porous carbon coating at the surface of the
fibres by thermal reactive chemical vapour deposition (RCVD) either in pressure-pulsed (P-RCVD) mode at low pressure or at
atmospheric pressure (AP-RCVD) with a H2/TiCl4 gaseous mixture. The conversion rate of C into TiC was studied as a function of the H2/TiCl4 pulse number for the P-RCVD method and as a function of the treatment time for the AP-RCVD method. Chemical and micro-structural
characterisations of the coatings were carried out by X-ray photoelectron spectroscopy, Auger electron spectroscopy and scanning
and transmission electron microscopies. Mechanical assessment was achieved by tensile tests at room temperature. For the P-RCVD
method, the conversion rate increased when the number of H2/TiCl4 pulses increased from 20 to 100. Once 20 H2/TiCl4 pulses were performed, an interlayer made of TiC was observed at the carbon coating/fibre interface indicating that the H2/TiCl4 gas has diffused inside the porous carbon and has reacted in depth and more particularly at the coating/fibre interface.
With 100 pulses, the carbon coating was totally converted. For the AP-RCVD method, the conversion rate increased when the
treatment time increased from 30 to 60 min. The reaction of conversion began preferentially at the outermost surface of the
carbon coating but several isolated TiC grains were also observed at the coating/fibre interface. At atmospheric pressure,
the gaseous mixture was more reactive than at low pressure whereas the diffusion of the gaseous species was limited inside
the carbon coating. The mechanical properties of the fibre decreased when the conversion rate of the carbon into TiC increased
both in P-RCVD and AP-RCVD. 相似文献
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《Materials Letters》2007,61(11-12):2356-2358
A process of thermal spraying and laser remelting of a Ni-clad graphite powder to form a coating on Ti–6Al–4V substrate was carried out. A good coating without cracks and pores was obtained. The microstructure of the coating was examined using SEM and EDS. The coating mainly consists of austenitic nickel as matrix and TiC dendrite as reinforcement. During the laser remelting process, a reaction between C and Ti occurred, which lead to an in-situ synthesis of TiC reinforcement in the coating. The microhardness of the coating was measured using a Vickers hardness tester. The average microhardness of the composite coating is HV 1000 and it is two times greater than that of the Ti–6Al–4V substrate. 相似文献
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TiN,TiC和Ti(C,N)涂层的性能及影响因素研究 总被引:1,自引:0,他引:1
TiN和TiC同属于NaCl形式的晶体结构,是同构互溶性的.Ti(C,N)是两者的固溶体.TiN和TiC及Ti(C,N)涂层具有优良的力学和摩擦学性能,作为硬质耐磨涂层,已用于切削刀具、钻头和模具等场合,具有广泛的应用前景.综述了国内外关于这3种涂层的研究成果.研究了影响其性能的若干因素,比较了它们的性能差异,为进一步优化涂层的性能及合理地选用涂层提供了参考.进一步的研究方向是高、低温及恶劣环境下涂层的性能以及更大载荷下涂层的摩擦学性能等.一些重要结果如下:(1)对TiN涂层而言,用CAPD比用CAIP制备时,涂层的摩擦因数小、结合强度大、硬度小;脉冲电压从550 V增大到750 V时,涂层脆性增加、结合强度减小;在多弧离子镀工艺中,500 ℃是最佳沉积温度,此时涂层的硬度和结合强度均最大.(2)对用反应磁控溅射制备的TiC涂层而言,用C2H2比用CH4制备时,涂层的硬度大;CH4分压在0.02~0.04 Pa范围内为最佳,此时TiC涂层的硬度和弹性模量最大,分别是30.9 GPa和343.0 GPa.(3)对Ti(C,N)涂层而言,随CH4:N2或C2H2:N2流量比的增大,其硬度增大;CH4:N2分压比对摩擦因数和磨损量的影响还与载荷的大小有关;TiCxN1-x涂层的硬度和弹性模量随x值而变化,当x为0.6左右时,硬度取最大值45 GPa,当x值为0.43左右时,弹性模量取最大值630 GPa. 相似文献
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Fabrication and oxidation resistance of titanium carbide-coated carbon fibres by reacting titanium hydride with carbon fibres in molten salts 总被引:2,自引:0,他引:2
Using carbon fibres and titanium hydride as a reactive carbon source and a metal source, respectively, a protective titanium carbide (TiC) coating was formed on carbon fibres in molten salts, composed of LiCl-KCl-KF, at 750-950 °C. The structure and morphology of the TiC coatings were characterised by X-ray diffraction and scanning electron microscopy, respectively. The oxidation resistance of the TiC-coated carbon fibres was measured by thermogravimetric analysis. The results reveal that control of the coating thickness is very important for improvement of the oxidation resistance of TiC-coated carbon fibres. The oxidative weight loss initiation temperature for the TiC-coated carbon fibres increases significantly when an appropriate coating thickness is used. However, thicker coatings lead to a decrease of the carbon fibres' weight loss initiation temperature due to the formation of cracks in the coating. The TiC coating thickness on carbon fibres can be controlled by adjusting the reaction temperature and time of the molten salt synthesis. 相似文献