A Breakdown Criterion of Free Molecular Flows and an Optimum Analysis of EBPVD

	A Breakdown Criterion of Free Molecular Flows and an Optimum Analysis of EBPVD
	Li SH(李帅辉); Fan J(樊菁); Shu YH(舒勇华); Li SH
会议录名称	Rarefied Gas Dynamics
	2009
页码	1105-1110
会议名称	26th International Symposium on Rarefied Gas Dynmaics (RGD26)
会议日期	JUN 20-JUL 25, 2008
会议地点	Kyoto, JAPAN
摘要	Two important issues in electron beam physical vapor deposition (EBPVD) are addressed. The first issue is a validity condition of the classical cosine law widely used in the engineering context. This requires a breakdown criterion of the free molecular assumption on which the cosine law is established. Using the analytical solution of free molecular effusion flow, the number of collisions (N-c) for a particle moving from an evaporative source to a substrate is estimated that is proven inversely proportional to the local Knudsen number at the evaporation surface. N-c = 1 is adopted as a breakdown criterion of the free molecular assumption, and it is verified by experimental data and DSMC results. The second issue is how to realize the uniform distributions of thickness and component over a large-area thin film. Our analysis shows that at relatively low evaporation rates the goal is easy achieved through arranging the evaporative source positions properly and rotating the substrate.
关键词	Free Molecular Assumption Breakdown Criterion Optimization Thin Film Ebpvd Physical Vapor-deposition Yttrium
WOS记录号	WOS:000265564800177
收录类别	CPCI-S
语种	英语
引用统计	被引频次：1[WOS] [WOS记录] [WOS相关记录]
文献类型	会议论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/25362
专题	高温气体动力学国家重点实验室
通讯作者	Li SH
推荐引用方式 GB/T 7714	Li SH,Fan J,Shu YH,et al. A Breakdown Criterion of Free Molecular Flows and an Optimum Analysis of EBPVD[C]Rarefied Gas Dynamics,2009:1105-1110.

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