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应用电子束蒸发硅,霍尔离子源电离甲烷,并辅助沉积的方法在反应烧结碳化硅(RB SiC)基底上沉积了碳化硅(SiC:H)改性薄膜.X射线衍射(XRD)测试表明制备的碳化硅改性薄膜为α相.通过控制沉积速率,制备了硬度为9.781~13.087GPa,弹性模量为89.344~123.413GPa的碳化硅改件薄膜.比较同样条件下镀制银膜的抛光良好微晶玻璃和经过精细抛光的改性 RB SiC,结果表明两者反射率相近;附着力实验表明,制备的薄膜和基底结合良好;在温度冲击实验下,制备的薄膜无龟裂和脱落. 相似文献
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应用电子枪蒸发硅,霍尔离子源电离甲烷,并辅助沉积的方法在反应烧结碳化硅(Reaction Bonded Silicon Carbide: RB SiC)基底上沉积了碳化硅(SiC:H)改性薄膜。XRD测试表明制备的碳化硅改性薄膜为α相。通过控制沉积速率,制备了硬度从9.781 GPa-13.087 GPa,弹性模量89.344 GPa-123.413 GPa的碳化硅改性薄膜。比较同样条件下都镀制银膜的抛光良好微晶玻璃和经过精细抛光的改性反应烧结碳化硅,两者有相近的反射率。附着力实验表明制备的薄膜和基底有良好的结合。在温度冲击实验下,制备的薄膜无龟裂和脱落。 相似文献
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大尺寸轻型碳化硅质镜体的制造与材料性能测试 总被引:1,自引:6,他引:1
利用凝胶注模(gel-casting)成型工艺制备了620 mm和700 mm×300 mm的碳化硅(SiC)轻型反射镜素坯,经过脱模、干燥、脱脂和反应烧结等工艺,制备了反应烧结SiC(RB-SiC)镜体。镜体经过加工和测试,结果表明:制备的RB-SiC内部结构均匀致密;力学性能和热学性能优异,抗弯强度、断裂韧性和热膨胀系数分别达到了350 MPa、 4.1 MPa·m1/2和2.67×10-6/K;镜体经抛光后的表面粗糙度RMS值可优于3 nm,适合用于制备空间用大尺寸轻型反射镜。 相似文献
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空间用碳化硅反射镜的设计制造与测试 总被引:8,自引:12,他引:8
碳化硅由于其优异的机械性能和热物理性能而成为颇具吸引力的反射镜材料。采用反应烧结碳化硅(RB-SiC)材料制备了空间用反射镜体,用化学气相沉积(CVD)工艺在镜体镜面沉积一层致密的碳化硅薄膜,反射镜采用蜂窝状背面开放式轻量化结构。对直径为250 mm反射镜的组织、性能做了一系列研究测试。结果表明:反射镜体为Si/SiC两相组织,薄膜为单相SiC,反射镜的机械、热性能优异,薄膜与基体结合强度为345.5 MPa,研磨后镜面表面粗糙度达到1.487 nm rms。采用本文工艺方法有能力制备米级直径的空间用碳化硅反射镜。 相似文献
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为了获得高密度、高性能、复杂结构的碳化硅陶瓷件,提出采用机械混合法制备含有黏结剂和乌洛托品固化剂的碳化硅复合粉体,对复合粉体进行激光选区烧结(SLS)形成陶瓷素坯,并对素坯进行气氛烧结和渗硅处理,使其与基体发生反应烧结,最终形成复杂陶瓷异形件。实验证明:若激光功率为8.0 W、扫描速率为2 000 mm/s、扫描间距为0.1 mm、单层厚度为0.15 mm,获得的 SLS 陶瓷样品密度和强度最好。对SLS试样进行合理的中温碳化和高温渗硅,所得碳化硅陶瓷烧结体的抗弯强度最高可达 81 MPa,相对密度大于86%。 相似文献
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Various light microscopy and SEM techniques have been used to study the temperature dependence of deformation structures around hardness indentations in highly brittle ceramics (including single crystals of silicon and silicon carbide and polycrystalline forms cf SiC, Si3N4 and B4C). Nomarski differential interferometry has enabled slip steps to be resolved around high-temperature indentations, allowing identification of the dominant slip systems and measurement of the extent of surface plasticity as a function of temperature. The occurrence of indentation fracture as a function of both temperature and specimen microstructure was studied by SEM methods (including stereo imaging), Nomarski differential interferometry and polarized reflection light microscopy. Generally, radial and lateral crack sizes increased with increasing temperature, due to increasing residual stresses around indentations caused by increasing indentation plasticity. Examples of microstructural control of crack paths are given for various single crystal and polycrystalline materials. 相似文献
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The selection of the right material for the mechanical stage of an electron beam lithography system is an important step in achieving the high accuracy required for submicron lithography. The material must be nonmagnetic, vacuum compatible, and strong enough for operation. It must possess mechanical properties to reduce static errors and dynamic errors, as well as electrical properties to minimize the E-beam deflection errors. After comparison of the most promising materials, silicon carbide is concluded to be the best material for an E-beam stage because of its low coefficient of thermal expansion, very high elastic modulus, light weight, and excellent hardness. Being semiconductive, it resolves both electric charge-up problems and beam deflection errors due to eddy current. 相似文献
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Fractography studies have shown that the strength-determining flaws in silicon carbide monofilaments are generally at the core/silicon carbide interface or in the vicinity of the outside, carbon-based coating. In tungsten-cored monofilaments like DERA Sigma, the W/SiC flaws primarily determine the strength. Fracture is accompanied by brittle failure of the tungsten. The crack propagates simultaneously outwards through the silicon carbide, inwards through the tungsten and also around the W/SiC interface before being deflected into the tungsten or out through the silicon carbide. Experiments depositing boundary layers between the tungsten and silicon carbide have resulted in significantly different fracture behaviour. The tungsten fails in a ductile manner and the strength-determining flaws are located predominantly at the outside surface of the silicon carbide. This behaviour is discussed in terms of models proposed by E. Martin and W. Curtin. It is thought that the work will ultimately lead to a significantly stronger, tungsten-based monofilament. 相似文献
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在轨道交通行业,碳化硅器件凭借其开关速度快、可实现高频化、低能耗等方面的优势,迅速得到了较为广泛的关注与应用。伴随着变换器的功率密度提高,与变换器配合的变压器更容易发生偏磁问题。该文对全碳化硅充电机进行主电路参数设计,并设计出具有变压器偏磁抑制功能的自动控制装置。通过试验,验证了该变压器偏磁抑制自动控制装置的有效性。 相似文献
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A method for coating released polysilicon microstructures with thin, uniform and conformal coatings of SiC derived from the single source precursor, 1,3-disilabutane (DSB) has been developed. This coating method has been successfully applied to micromechanical test devices which allow evaluation of friction and wear properties of the coating. Here, data on the coefficient of static friction of SiC coatings produced from DSB is presented. Also, a comparative wear study for devices which have been oxidized, treated with an anti-adhesion coating, and SiC coated is shown. Wear is examined by scanning electron microscopy (SEM) on devices which have been cycled repetitively under a nominal load. It is found that the application of a few nanometers-thin SiC coating provides exceptional wear resistance as well as significant reduction in friction on the microscale. 相似文献
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考察了以SiC和碳粉为主要原料制备的不同密度和游离硅含量的反应烧结SiC陶瓷的耐酸碱腐蚀性能,结果表明:游离硅含量及其分布状况是决定SiC陶瓷耐化学腐蚀性能的主要因素。密度为3.16 g/cm3的反应烧结SiC耐化学腐蚀性能显著优于密度为3.07 g/cm3的材料。同等密度但含少量游离碳的高密度材料耐腐蚀性能更好,在98℃5%HF/5%HNO3(质量分数)中腐蚀30 h后失重量仅为中等密度材料的1/17.4。混酸腐蚀时反应烧结SiC初始1 h腐蚀量与材料中游离硅的体积含量呈线性关系,其后,高、低密度材料的腐蚀失重量的比值减小。 相似文献
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The friction and wear behaviour of eight different SiC TiC TiB2 composite materials, with a practically constant SiC:TiC ratio of 1 and an increasing amount of TiB2, was determined comparatively in oscillating sliding tests at room temperature under unlubricated conditions. The influence of the relative humidity (RH) of the surrounding air was investigated in tests in dry, normal, and moist air. All tests were performed against SiC balls and Al2O3 balls as counterbodies. The friction was affected by RH but barely at all by the composition of the composites. The wear resistance of the composites was found to be improved considerably by addition of TiB2 in the range 20–60%. The highest wear resistance of the system was found when Al2O3 was used as the counterbody material. 相似文献
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研究了三种典型的碳化硅光学材料CVD SiC、HP SiC以及RB SiC的材料去除机理与可抛光性,并对其进行了超光滑抛光试验。在分析各种材料制备方法与材料特性的基础上,通过选择合理的抛光工艺参数,均获得了表面粗糙度优于Rq=2nm(采样面积为0.71mm×0.53mm)的超光滑表面。试验结果表明:研磨过程中,三种碳化硅光学材料均以脆性断裂的方式去除材料,加工表面存在着裂纹以及材料脱落留下的缺陷;抛光过程中,CVD SiC主要以塑性划痕的方式去除材料,决定表面粗糙度的主要因素为表面微观划痕的深度;HP SiC同时以塑性划痕与晶粒脱落的形式去除材料,决定表面粗糙度的主要因素为碳化硅颗粒大小以及颗粒之间微孔的尺寸;RB SiC为多组分材料,决定其表面粗糙度的主要因素为RB SiC三种组分之间的去除率差异导致的高差。
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