【作者】 王雪；

【导师】 朱小鹏；

【作者基本信息】 大连理工大学 ， 材料表面工程， 2010， 硕士

【摘要】 采用强流脉冲离子束技术对碳基材料进行高热负荷性能测试,模拟托卡马克核聚变反应堆装置中等离子体与壁材料的作用过程,研究核聚变装置第一壁材料在高热负荷和高粒子通量条件下的烧蚀行为,为第一壁材料的研发创造基础条件。采用TEMP-6型强流脉冲离子束装置,在加速电压300 kV,脉冲宽度75 ns,热流参数180-400 MWm-2s1/2,对核聚变第一壁备选材料——C／C复合材料、石墨、玻璃碳、SiC涂层材料进行1-10次辐照实验研究。采用电子天平、扫描电子显微镜、表面轮廓仪、X射线衍射仪及Raman光谱仪测试表征样品烧蚀率、表面形貌、粗糙度及相结构变化,分析碳基第一壁备选材料表面烧蚀影响因素,探讨其烧蚀机理,对比抗热流冲击能力,为择优选取材料提供实验依据。以45°、90°两种入射角辐照C／C复合材料和石墨试样。C／C复合材料表面碳纤维首先发生断裂与脱落,石墨基体随后产生裂纹。而石墨表面碎屑发生脱落,并因选择性烧蚀形成大量孔洞；随后转变为大面积均匀烧蚀,原始孔隙和空腔被重熔填实,辐照表面致密化,不同辐照角度对C／C复合材料的影响不显著,而石墨在斜入射离子辐照下的损伤比垂直入射更严重。经辐照两种材料的相结构均未发生明显变化。玻璃碳首先发生均匀烧蚀,出现均匀细小烧蚀颗粒,表面变粗糙,粗糙度由原始的nm级迅速上升至μm级。随后发生选择性起泡烧蚀,出现气泡状微凸,一些微凸表层破裂并剥落,粗糙度先增大后减小。高热负荷作用导致了玻璃碳的石墨化倾向。横向对比发现,玻璃碳的抗热流冲击能力最强。对SiC涂层进行辐照,原始疏松多孔的表面在孔边缘发生择优烧蚀,边缘圆滑化,随后大面积重熔,孔隙率下降,呈现较光滑表面,但是出现沟壑状大尺寸孔隙。表层由原始的C、SiC相转变为C、SiC和Si三相混合状态。研究表明,SiC涂层显著提高了石墨抗烧蚀性能。更多还原

【Abstract】 High-intensity pulsed ion beam (HIPIB) technique was employed as a useful tool to simulate plasma-material interactions, especially material ablation and erosion in Tokamak for evaluating and developing the first-wall materials.In this study, first-wall candidate materials-C/C composite, graphite G347, glassy carbon and SiC coating were investigated in TEMP-6 HIPIB apparatus. Typical HIPIB parameters for the irradiation were heat flux parameter of 180-400 MWm-2s1/2, accelerating voltage of 300 kV, pulse width of 75 ns and 1-10 shots. Electronic balance, scanning electron microscopy, X-ray diffractometer and Raman spectroscope were used to characterize weight loss, surface morphology and phase structure, to evaluate the ablation behaviors of the carbon-based materials under high heat flux.C/C composite and graphite G347 samples were irradiated with shot angle of 45°and 90°. Fracture and exfoliation of carbon fibers were observed at first in C/C composite, obvious ablation of graphite matrix were also found and noticeable cracking occurred on the graphite matrix when increasing the shot number. The irradiated graphite G347 presented a surface of selective ablation firstly, then turned to uniform ablation on a larger scale. It is difficult to estimate the influence of shot angle on the irradiated C/C composite, but it is easier to generate damage on graphite G347 at smaller angle. X-ray diffraction analysis showed that the phase structure of both materials had little change after irradiation.The irradiated glassy carbon presented uniform ablation and many homogeneous fine particles on the whole surface at first. Surface roughness increased from nm degree toμm degree. Then blebs, some of which bursted and exfoliated, appeared because the ablation form changed into selective bubbly ablation. Surface roughness increased, then decreased. So the resistance of ablation enhanced. Raman spectroscope analysis showed that the glassy carbon seemed like to change into graphite. we found the glassy carbon has the best resistance of high heat flux in these three materials.The SiC coatings irradiated by HIPIB also. The original loose and multihole-surface presented preferential ablation on the edge of holes firstly so that the edge became smooth. Then surface was remelted on a large scale under multi-shot exposure. The porosity fall down, but a lot of small tuber formed. X-ray diffraction analysis showed that the phase structure of SiC coatings changed from C, SiC into C,SiC and Si.更多还原